Antibiotics

4 pages, 177 KB

Open AccessEditorial

Plants, Lichens, Fungi, and Algae Extracts and Derivatives with Antimicrobial Properties for Nutrition and Health

by Violeta Popovici, Emma Adriana Ozon, Andreea Letiția Arsene and Verginica Schröder

Antibiotics 2026, 15(1), 111; https://doi.org/10.3390/antibiotics15010111 - 22 Jan 2026

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Plants are a rich source of bioactive compounds with a wide range of nutritional and therapeutic properties [...] Full article

(This article belongs to the Special Issue Plants, Lichens, Fungi, and Algae Extracts and Derivatives with Antimicrobial Properties for Nutrition and Health)

20 pages, 682 KB

Open AccessArticle

Exploring the Environmental Resistome and Bacterial Novelty in Marine Isolates from the North Portuguese Coast

by Ofélia Godinho, Olga Maria Lage and Sandra Quinteira

Antibiotics 2026, 15(1), 110; https://doi.org/10.3390/antibiotics15010110 - 22 Jan 2026

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Abstract

Background/Objectives: It is of the utmost importance to study environmental bacteria, as these microorganisms remain poorly characterized regarding their diversity, antimicrobial resistance, and impact on the global ecosystem. This knowledge gap is particularly pronounced for marine bacteria. In this study, we aimed to [...] Read more.

Background/Objectives: It is of the utmost importance to study environmental bacteria, as these microorganisms remain poorly characterized regarding their diversity, antimicrobial resistance, and impact on the global ecosystem. This knowledge gap is particularly pronounced for marine bacteria. In this study, we aimed to isolate bacteria from different marine samples and to gain insights into the environmental bacterial resistome, an aspect that remains largely neglected. Methods: Bacteria were isolated from several marine sources using two different culture media, and their identification was based on 16S rRNA gene analysis. Whole-genome sequencing was performed for selected isolates belonging to novel taxa. Antimicrobial susceptibility to seven antibiotics was evaluated using the disk diffusion method. Results: A total of 171 bacterial isolates belonging to the phyla Pseudomonadota, Bacteroidota, Planctomycetota, Actinomycetota, and Bacillota were obtained from diverse marine samples. The most abundant group belonged to the class Alphaproteobacteria. Thirty isolates represented novel taxa, comprising 16 new species and one new genus. Despite the challenges associated with determining antibiotic resistance profiles in environmental bacteria, only one isolate (1.8%) was pan-susceptible, whereas 54 (98.2%) showed resistance to at least one of the tested antibiotics. Moreover, 33 isolates exhibited a multidrug-resistant phenotype. Genome analysis of four novel taxa revealed the presence of an incomplete AdeFGH efflux pump. Conclusions: This study highlights the high bacterial diversity in marine environments, the striking prevalence of antibiotic resistance, and the major methodological challenges in studying environmental bacteria. Importantly, it emphasizes the relevance of culturomics-based approaches for uncovering hidden microbial diversity and characterizing environmental resistomes. Full article

(This article belongs to the Special Issue Genetic Characterization of Antimicrobial Resistance under the One Health Approach)

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13 pages, 2630 KB

Open AccessArticle

Rectal Colonization by Carbapenemase-Producing Enterobacterales in a Tertiary Care Hospital in Havana, Cuba

by Haiyang Yu, Yenisel Carmona, Vismayda Bouza, María Karla González, Gonzalo Estevez Torres, Valia Ramos Rodríguez, Alberto Hernández González, Nobumichi Kobayashi, Meiji Soe Aung, Patricia Ruiz-Garbajosa, Rafael Cantón and Dianelys Quiñones Pérez

Antibiotics 2026, 15(1), 109; https://doi.org/10.3390/antibiotics15010109 - 22 Jan 2026

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Abstract

Introduction: Rectal colonization by carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) is a risk factor for subsequent infections, which are associated with high mortality rates. Methods: A cross-sectional study was conducted. Rectal swabs were collected from 297 patients within 48 h of admission to eight high-prevalence [...] Read more.

Introduction: Rectal colonization by carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE) is a risk factor for subsequent infections, which are associated with high mortality rates. Methods: A cross-sectional study was conducted. Rectal swabs were collected from 297 patients within 48 h of admission to eight high-prevalence CP-CRE hospital departments, with follow-up swabs taken weekly for up to 4 weeks. Species identification, antimicrobial susceptibility testing, and genetic detection of carbapenemases were performed. The genetic relationship among isolates was assessed using ERIC-PCR, combined with epidemiological data, to investigate subsequent infections. Results: Fecal carriage of CP-CRE was detected in 15.5% (46/297) of patients- All carbapenemases were metallo-betalactamases, with dominance of NDM-producing Klebsiella pneumoniae. NDM + VIM-producing Escherichia coli were also detected. Among carriers, 26.1% were colonized by two different CRE species, and 86.9% had a history of prior hospitalization. Molecular analysis revealed clonal expansion, suggesting outbreaks among colonized patients. Additionally, 17.4% (8/46) of colonized patients developed an infection, which was significantly associated with urinary catheter use (p = 0.040), mechanical ventilation (p = 0.044), and surgical procedures (p = 0.040). Conclusions: rectal colonization by CP-CRE in hospitalized patients is a serious epidemiological concern, with evidence of clonal spread and subsequent infection in colonized patients. NDM-producing K. pneumoniae was also predominant, detecting co-production of NDM + VIM in E. coli. These findings underscore the urgent need to implement epidemiological surveillance cultures to improve the prevention and control of CP-CRE infections in Cuban hospitals. Full article

(This article belongs to the Special Issue Antimicrobial Resistance and Epidemiological Study of Clinically Relevant Pathogens)

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17 pages, 1030 KB

Open AccessArticle

Benchmarking: A Tool for Veterinary Practices to Improve Prudent Use of Antibiotics in Cats and Dogs in Switzerland

by Anaïs Léger, Heinzpeter Schwermer, Guy-Alain Schnidrig, Didier Wernli, Jacques Schrenzel and Dagmar Heim

Antibiotics 2026, 15(1), 108; https://doi.org/10.3390/antibiotics15010108 - 22 Jan 2026

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Abstract

Background/Objectives: Antibiotic use (ABU) in cats and dogs is a potential public health issue due to its direct contribution to the emergence of antibiotic resistance. In Switzerland, data on animal antibiotic treatments has been collected since 2020 via the Information System for [...] Read more.

Background/Objectives: Antibiotic use (ABU) in cats and dogs is a potential public health issue due to its direct contribution to the emergence of antibiotic resistance. In Switzerland, data on animal antibiotic treatments has been collected since 2020 via the Information System for ABU in Veterinary Medicine. This study focuses on the first implementation of a national benchmarking tool for ABU in cats and dogs in veterinary practices. Methods: The benchmarking tool is based on a practice-level indicator derived from the number of therapy days (pATI). Practices are compared separately for small animal practices and mixed practices, and for each animal species. The pATI is calculated based on the number of therapy days and is normalized by the number of consultations per species and per year. Practices were classified into four ABU categories based on their pATI: very high, high, acceptable, and no ABU. Thresholds for these categories are set according to Swiss legislation, using the 75th and 95th percentiles of the pATI values of all comparable practices. Results: By 2025, benchmarks were implemented in 686 veterinary facilities; a total of 667 (97.2%) received a pATI classification for ABU in dogs and 670 (97.7%) for ABU in cats. The median pATI was higher for cats than for dogs across all practice types. Similarly, the 75th and 95th percentile thresholds were also almost always twice as high for cats as for dogs across all practice types. Conclusions: To our knowledge, this is the first time a benchmarking tool for ABU has been implemented at a national level for cats and dogs. The benchmarking tool is expected to drive long-term changes in ABU practices. Full article

(This article belongs to the Section Antibiotics in Animal Health)

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22 pages, 639 KB

Open AccessArticle

Psychometric Validation of the Community Antimicrobial Use Scale (CAMUS) in Primary Healthcare and the Implications for Future Use

by Nishana Ramdas, Natalie Schellack, Corrie Uys, Brian Godman, Stephen M. Campbell and Johanna C. Meyer

Antibiotics 2026, 15(1), 107; https://doi.org/10.3390/antibiotics15010107 - 21 Jan 2026

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Abstract

Background/Objectives: Patient-level factors strongly influence antimicrobial resistance (AMR) through the pressure applied to healthcare professionals to prescribe antibiotics even for self-limiting viral infections, enhanced by knowledge and attitude concerns. This includes Africa, with high levels of AMR. However, validated measurement tools for African [...] Read more.

Background/Objectives: Patient-level factors strongly influence antimicrobial resistance (AMR) through the pressure applied to healthcare professionals to prescribe antibiotics even for self-limiting viral infections, enhanced by knowledge and attitude concerns. This includes Africa, with high levels of AMR. However, validated measurement tools for African primary healthcare (PHC) are scarce. This study evaluated the reliability, structural validity, and interpretability of the Community Antimicrobial Use Scale (CAMUS) in South Africa. Methods: A cross-sectional survey was conducted with 1283 adults across 25 diverse public PHC facilities across two provinces. The 30-item theory-based tool underwent exploratory and confirmatory factor analysis (EFA/CFA), reliability, and validity testing. Results: EFA identified a coherent five-factor structure: (F1) Understanding antibiotics; (F2) Social and behavioural norms; (F3) Non-prescribed use; (F4) Understanding of AMR; and (F5) Attitudes. Internal consistency was strongest for knowledge and misuse domains (alpha approximation 0.80). Test–retest reliability was good-to-excellent (ICC: 0.72–0.89). CFA confirmed acceptable composite reliability (CR ≥ 0.63). Although average variance extracted (AVE) was low for broader behavioural constructs, indicating conceptual breadth, it was high for AMR knowledge (0.737). Construct validity was supported by positive correlations with health literacy (r = 0.48) and appropriate use intentions (r = 0.42). Measurement error metrics (SEM = 1.59; SDC = 4.40) indicated good precision for group-level comparisons. Conclusions: CAMUS demonstrated a theoretically grounded structure with robust performance in knowledge and misuse domains. While social and attitudinal domains require refinement, we believe the tool is psychometrically suitable for group-level antimicrobial use surveillance and programme evaluation in South African PHC settings and wider to help with targeting future educational programmes among patients. Full article

(This article belongs to the Special Issue Therapy of Infectious Diseases Among Children and Adults: The Role of Antibiotics in Daily Practice)

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9 pages, 221 KB

Open AccessArticle

Comparison of a Single-Shot Antibiotic Protocol Compared to a Conventional 5-Day Antibiotic Protocol in Equine Diagnostic Laparotomy Regarding Pre- and Postoperative Colonization with Multi-Drug-Resistant Indicator Pathogens

by Sabita Diana Stöckle, Dania Annika Kannapin, Roswitha Merle, Antina Lübke-Becker and Heidrun Gehlen

Antibiotics 2026, 15(1), 106; https://doi.org/10.3390/antibiotics15010106 - 21 Jan 2026

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Abstract

Objective: The emergence and spread of multi-drug-resistant (MDR) bacteria pose a growing threat in veterinary medicine, particularly in equine hospitals. This study investigated the colonization and infection dynamics of horses undergoing emergency laparotomy with two distinct antibiotic protocols (single-shot versus 5-day protocol) during [...] Read more.

Objective: The emergence and spread of multi-drug-resistant (MDR) bacteria pose a growing threat in veterinary medicine, particularly in equine hospitals. This study investigated the colonization and infection dynamics of horses undergoing emergency laparotomy with two distinct antibiotic protocols (single-shot versus 5-day protocol) during hospitalization. Methods: Nasal swabs and fecal samples were collected from 67 horses undergoing emergency laparotomy at clinic admission as well as on postoperative days 3 and 10. These were screened for multi-drug-resistant indicator pathogens. As multi-drug-resistant indicator pathogens, methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-E), and bacteria belonging to the Acinetobacter baumannii complex were defined. Results: Preoperatively, 6.2% of horses tested positive for MRSA and 13% for ESBL-E. An increase in colonization was observed on day 3 postoperatively, with 62.1% of nasal swabs and 86.4% of fecal samples testing positive for MDR organisms. On day 10, 53.4% of nasal swabs and 62.5% of fecal samples tested positive for indicator pathogens. Surgical site infection developed in five horses, two of which tested positive for MRSA in both nasal and wound samples during hospitalization, supporting the potential role of nasal carriage as a source of infection. Furthermore, all horses tested positive for ESBL-E during at least one time-point during hospitalization, and Enterobacterales (MDR in two surgical site infections (SSI)) were involved in all surgical site infections. No significant differences were observed between the two antibiotic treatment groups regarding colonization rates with indicator pathogens during hospitalization. However, the results indicate that hospitalization itself contributes to increased colonization with resistant bacteria. A clear limitation of the study is the restricted number of sampled horses and the lack of environmental contamination data. Non-sampled hospitalized horses with and without antibiotic treatment may have acted as reservoirs for MDR bacteria. Conclusion: The findings emphasize the need for routine environmental monitoring and strict adherence to hygiene protocols in equine clinics to reduce the risk of nosocomial transmission. Ongoing surveillance and infection control strategies are essential to mitigate the spread of MDR pathogens in veterinary settings. Full article

(This article belongs to the Special Issue Antibiotic Resistance in Bacterial Isolates of Animal Origin)

19 pages, 4620 KB

Open AccessArticle

Phytochemical Characterization and Antimicrobial Properties of a Hydroalcoholic Extract of Tristerix corymbosus (L) Kuijt, a Chilean Mistletoe Species Hosted on Salix babylonica (L)

by Alejandro A. Hidalgo, Sergio A. Bucarey, Beatriz Sepúlveda, Sebastián Cumsille-Escandar, Alejandro Charmell, Nicolás A. Villagra, Andrés Barriga, Consuelo F. Martínez-Contreras, Jorge Escobar, José L. Martínez and Maité Rodríguez-Díaz

Antibiotics 2026, 15(1), 105; https://doi.org/10.3390/antibiotics15010105 - 21 Jan 2026

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Abstract

Background/Objectives: The genus Tristerix comprises at least ten species, found from southern Chile to Colombia in South America. In Chile, several species of these hemiparasitic plants are known as quitral or quintral. Quitral, mainly T. corymbosus (syn. T. tetrandus), is used in [...] Read more.

Background/Objectives: The genus Tristerix comprises at least ten species, found from southern Chile to Colombia in South America. In Chile, several species of these hemiparasitic plants are known as quitral or quintral. Quitral, mainly T. corymbosus (syn. T. tetrandus), is used in alternative medicine for its anti-inflammatory, digestive, hemostatic, hypocholesterolemic, and wound-healing properties. This study investigates the phytochemical composition and antimicrobial properties of T. corymbosus. Methods: A hydroalcoholic extract of T. corymbosus was prepared from leaves and small branches. The addition of methanol, on the extract, produced precipitation allowing us to isolate a methanol-soluble fraction, a brown powder obtained after filtration, and a tar-like residue remaining in the flask. These fractions were resuspended and tested for antimicrobial activity. Results: All fractions showed activity against Streptococcus pyogenes, but not E. coli. The brown powder exhibits the strongest potency against Gram-positive bacteria, some Gram-negative and C. albicans. HPLC-MS analysis revealed presence of lipidic compounds with surfactant properties. Conclusions: The abundant lipidic molecules present in the analyzed fraction likely account for the antimicrobial effects through affecting membrane structure of microorganisms supporting the traditional wound-healing uses of T. corymbosus in ancestral medicine. Full article

(This article belongs to the Special Issue Advances in Antimicrobial Compounds: Exploring Natural, Synthetic, and Repositioned Drugs)

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39 pages, 23725 KB

Open AccessFeature PaperArticle

Discovery of Coerumycin, a Cinnamycin-like Lantibiotic from Actinomadura coerulea TMS085

by Denis Iliasov and Thorsten Mascher

Antibiotics 2026, 15(1), 104; https://doi.org/10.3390/antibiotics15010104 - 21 Jan 2026

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Abstract

Background: The current rise in multidrug-resistant pathogens highlights the urgent need for the discovery of novel antibacterial agents with potential clinical applications. A considerable proportion of these developed resistances may be attributable to the intrinsic response of bacteria to antibiotic-induced stress conditions in [...] Read more.

Background: The current rise in multidrug-resistant pathogens highlights the urgent need for the discovery of novel antibacterial agents with potential clinical applications. A considerable proportion of these developed resistances may be attributable to the intrinsic response of bacteria to antibiotic-induced stress conditions in the environment. Consequently, the identification and characterization of genetic alterations in physiological processes in response to antibiotics represent promising strategies for the discovery and characterization of naturally produced novel antibacterial agents. This study investigated the antimicrobial activity of an antimicrobial active isolate Actinomadura coerulea derived from a meerkat fecal sample. Methods: The production of secondary metabolites that potentially compromise bacterial cell wall integrity was confirmed by the induction of promoter activity in whole-cell biosensors in which an antibiotic-inducible promoter was fused to the luciferase cassette. During plate-based biosensor assays, we identified naturally resistant Bacillus subtilis colonies growing in the zone of inhibition around A. coerulea colonies. After these successive rounds of selection, highly resistant spontaneous B. subtilis mutants had evolved that were subjected to whole-genome sequencing. Results: Non-silent mutations were identified in pssA, which encodes a phosphatidylserine synthase; mdtR, as a gene for the repressor of multidrug resistance proteins, and yhbD, whose function is still unknown. A new cinnamycin-like molecule, coerumycin, was discovered based on the physiological role of PssA and comprehensive genomic analysis of A. coerulea. Additional experiments with cell extracts containing coerumycin as well as the cinnamycin-like compound duramycin confirmed that the interaction between coerumycin and the bacterial cell envelope is inhibited by a loss-of-function mutation in pssA. Conclusion: Our approach demonstrates that combining the exploration of niche habitats for actinomycetes with whole-cell biosensor screening and characterization of natural resistance development provides a promising strategy for identifying novel antibiotics. Full article

(This article belongs to the Section Antimicrobial Peptides)

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15 pages, 3763 KB

Open AccessArticle

Understanding the Financial Implications of Antimicrobial Resistance Surveillance in Nepal: Context-Specific Evidence for Policy and Sustainable Financing Strategies

by Yunjin Yum, Monika Karki, Dan Whitaker, Kshitij Karki, Ratnaa Shakya, Hari Prasad Kattel, Amrit Saud, Vishan Gajmer, Pankaj Chaudhary, Shrija Thapa, Rakchya Amatya, Timothy Worth, Claudia Parry, Wongyeong Choi, Clemence Nohe, Adrienne Chattoe-Brown, Deepak C. Bajracharya, Krishna Prasad Rai, Sangita Sharma, Kiran Pandey, Bijaya Kumar Shrestha, Runa Jha and Jung-Seok Lee Show full author list Hide full author list

Antibiotics 2026, 15(1), 103; https://doi.org/10.3390/antibiotics15010103 - 20 Jan 2026

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Abstract

Background/Objectives: Antimicrobial resistance (AMR) surveillance is a cornerstone of national AMR strategies but requires sustained, cross-sectoral financing. While the need for such financing is well recognized, its quantification remains scarce in low- and middle-income countries. This study aimed to estimate the full [...] Read more.

Background/Objectives: Antimicrobial resistance (AMR) surveillance is a cornerstone of national AMR strategies but requires sustained, cross-sectoral financing. While the need for such financing is well recognized, its quantification remains scarce in low- and middle-income countries. This study aimed to estimate the full costs of AMR surveillance across the human health, animal health, and food sectors (2021–2030) in selected facilities in Nepal and generate evidence to inform sustainable financing. Methods: A bottom-up micro-costing approach was used to analyze data from five sites. Costs were adjusted for inflation using projected gross domestic product deflators, and probabilistic sensitivity analyses were conducted to assess uncertainty in laboratory sample volumes under four scenarios. Results: The total cost of AMR surveillance in Nepal was $6.7 million: $3.4 million for human health (50.3% out of the aggregated costs), $2.7 million for animal health (39.8%), and $0.7 million for the food sector (9.9%). Laboratories accounted for >90% of total costs, with consumables and personnel as the main cost drivers. Average cost per sample was $150 (animal), $64 (food), and $6 (human). Conclusions: This study offers the first robust, multi-sectoral 10-year cost estimates of AMR surveillance in Nepal. The findings highlight that sustaining AMR surveillance requires predictable domestic financing, particularly to cover recurrent laboratory operations as donor support declines. These results provide cost evidence to support future budgeting and policy planning toward sustainable, nationally financed AMR surveillance in Nepal. Full article

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14 pages, 1400 KB

Open AccessArticle

Molecular Epidemiology of Carbapenem-Resistant Pseudomonas aeruginosa Before the COVID-19 Pandemic: Resistance Profiles and Clonality in a Tertiary-Care Hospital

by Raúl Eduardo Loredo-Puerta, Perla Niño-Moreno, Raúl Alejandro Atriano-Briano, Katy Lizbeth Martínez-Alaniz, Nubia Baltazar-Benitez, Luis Fernando Pérez-González, Mónica Lucía Acebo-Martínez, Adriana Berenice Rousset-Román and Edgar A. Turrubiartes-Martínez

Antibiotics 2026, 15(1), 102; https://doi.org/10.3390/antibiotics15010102 - 20 Jan 2026

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Abstract

Background/Objectives: Pseudomonas aeruginosa is an opportunistic pathogen frequently implicated in healthcare-associated infections, particularly ventilator-associated pneumonia and other device-related infections. The global emergence of carbapenem-resistant P. aeruginosa (CRPA) represents a major clinical challenge due to its limited therapeutic options and high mortality rates. [...] Read more.

Background/Objectives: Pseudomonas aeruginosa is an opportunistic pathogen frequently implicated in healthcare-associated infections, particularly ventilator-associated pneumonia and other device-related infections. The global emergence of carbapenem-resistant P. aeruginosa (CRPA) represents a major clinical challenge due to its limited therapeutic options and high mortality rates. Methods: Relevant clinical data were obtained from medical records. Isolates were identified via 16S PCR, and antimicrobial susceptibility testing was performed using the Vitek2 Compact system following CLSI guidelines. Carbapenemase genes (blaGES, blaKPC, blaIMP, blaNDM, blaVIM) were detected via PCR. Clonal relationships were determined via RAPD-PCR, and some sequence types were assigned according to the global P. aeruginosa MLST database. Results: In this study, 40 non-duplicate CRPA isolates were collected from 35 patients in a tertiary-care hospital in Mexico. Most isolates originated from adult patients, predominantly from tracheal aspirates (32.5%) and urine cultures (25.0%). Mechanical ventilation was the most common invasive device associated with infection, and the overall mortality rate reached 14.3%. Antimicrobial susceptibility testing showed that 95% of isolates exhibited a multidrug-resistant phenotype, with high resistance rates to ciprofloxacin (70.0%) and β-lactams. Carbapenemase genes were detected in 55% of isolates, mainly bla_IMP, bla_GES, and bla_VIM, either alone or in combination. Notably, this is the first report of ST309 (bla_IMP), ST411 (bla_GES + bla_IMP), and ST167 (bla_GES + bla_VIM) carrying carbapenemase genes in Mexico. Conclusions: These findings highlight the persistence and genetic diversity of CRPA circulating in hospital settings and emphasize the urgent need for strengthened genomic surveillance and infection control programs to prevent the spread of these high-risk multidrug-resistant clones. Full article

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12 pages, 1058 KB

Open AccessArticle

Environmental Dissemination of Antimicrobial Resistance: A Resistome-Based Comparison of Hospital and Community Wastewater Sources

by Taito Kitano, Nobuaki Matsunaga, Takayuki Akiyama, Takashi Azuma, Naoki Fujii, Ai Tsukada, Hiromi Hibino, Makoto Kuroda and Norio Ohmagari

Antibiotics 2026, 15(1), 99; https://doi.org/10.3390/antibiotics15010099 - 19 Jan 2026

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Abstract

Background/Objectives: Comparative analysis of antimicrobial resistomes in hospital and community wastewater can provide valuable insights into the diversity and distribution of antimicrobial resistance genes (ARGs), contributing to the advancement of the One Health approach. This study aimed to characterize and compare the resistome [...] Read more.

Background/Objectives: Comparative analysis of antimicrobial resistomes in hospital and community wastewater can provide valuable insights into the diversity and distribution of antimicrobial resistance genes (ARGs), contributing to the advancement of the One Health approach. This study aimed to characterize and compare the resistome profiles of wastewater sources from a hospital and community. Methods: Longitudinal metagenomic analysis was conducted on wastewater samples collected from the National Center for Global Health and Medicine (hospital) and a shopping mall (community) in Tokyo, Japan, between December 2019 and September 2023. ARG abundance was quantified using reads per kilobase per million mapped reads (RPKM) values, and comparative analyses were performed to identify the significantly enriched ARGs in the two sources. Results: A total of 46 monthly wastewater samples from the hospital yielded 825 unique ARGs, with a mean RPKM of 2.5 across all detected genes. In contrast, 333 ARGs were identified in the three shopping mall wastewater samples, with a mean RPKM of 2.1. Among the ARGs significantly enriched in the hospital samples, 23, including genes conferring resistance to aminoglycosides (nine groups) and β-lactam antibiotics (eight groups), exhibited significantly high RPKM values. No ARGs were found to be significantly enriched in the community wastewater samples. Conclusions: This study highlights the higher diversity and abundance of ARGs, particularly those conferring resistance to aminoglycosides and β-lactam antibiotics including carbapenems, in hospital wastewater than in community wastewater. These findings underscore the importance of continuous resistome monitoring of hospital wastewater as part of the integrated One Health surveillance strategy. Full article

(This article belongs to the Special Issue Antibiotic Resistance in Wastewater Treatment Plants)

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13 pages, 1017 KB

Open AccessArticle

Impact of the COVID-19 Pandemic on the Outcomes of a Multifaceted Program on Antibiotic Prescribing in Primary Care Among Children Under Three Years of Age

by Gema Martín-Ayala, Santiago Alfayate-Miguélez, Casimiro Jiménez-Guillén, Manuel Alcaraz-Quiñonero, Antonio Iofrío-De Arce and José Arnau-Sánchez

Antibiotics 2026, 15(1), 101; https://doi.org/10.3390/antibiotics15010101 - 19 Jan 2026

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Abstract

Background/objective: Inappropriate antibiotic use in paediatric populations is a leading driver of antimicrobial resistance. In the Murcia Region, Spain, the Purapi program promotes the rational use of antibiotics among children under 3 years of age. This study aimed to analyse antibiotic use [...] Read more.

Background/objective: Inappropriate antibiotic use in paediatric populations is a leading driver of antimicrobial resistance. In the Murcia Region, Spain, the Purapi program promotes the rational use of antibiotics among children under 3 years of age. This study aimed to analyse antibiotic use in this age group during the pandemic period (2020–2023) and to assess the impact of the COVID-19 pandemic on the effectiveness of a multifaceted program promoting appropriate antibiotic use. Methods: A retrospective, multicentre, population-based study was conducted in primary care using data from 2019 to 2024. Systemic antibiotic use (ATC J01 group) among children under three years was measured as defined daily doses per 1000 inhabitants per day (DHD). Differences across years and healthcare areas were assessed using analysis of variance (ANOVA) with Bonferroni correction. Results: Antibiotic consumption decreased by 49% in 2020 compared to 2019, coinciding with the implementation of national COVID-19 containment measures. From 2021 onward, a gradual increase was observed; however, by 2024, levels remained 9% below pre-pandemic values. Penicillins account for 75% of prescriptions, mainly amoxicillin and amoxicillin–clavulanic acid. While variability across healthcare areas decreased during the pandemic, variability among primary care centres increased. Conclusions: The pandemic resulted in a temporary reduction in antibiotic use, followed by a partial rebound. Ongoing educational and stewardship interventions within the Purapi framework were instrumental in maintaining rational prescribing and may have contributed to maintaining reduced antibiotic consumption among children under three years of age during and after the pandemic. Strengthening and harmonising these initiatives is essential to ensure consistent paediatric antibiotic stewardship in primary care. Full article

(This article belongs to the Special Issue Inappropriate Use of Antibiotics in Pediatrics)

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53 pages, 8694 KB

Open AccessReview

Lipopeptide Engineering: From Natural Origins to Rational Design Against Antimicrobial Resistance

by Shi-Yu Xie, Fang-Jing He, Ying-Ying Yang, Yan-Fei Tao and Xu Wang

Antibiotics 2026, 15(1), 100; https://doi.org/10.3390/antibiotics15010100 - 19 Jan 2026

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Abstract

Lipopeptides (LPs) have evolved from naturally occurring compounds to key therapeutic agents against multidrug-resistant (MDR) bacterial infections. However, their expanding clinical use has triggered emerging resistance mechanisms, posing serious challenges to anti-infective therapy. This systematic review outlines the development of LP resistance and [...] Read more.

Lipopeptides (LPs) have evolved from naturally occurring compounds to key therapeutic agents against multidrug-resistant (MDR) bacterial infections. However, their expanding clinical use has triggered emerging resistance mechanisms, posing serious challenges to anti-infective therapy. This systematic review outlines the development of LP resistance and highlights innovative strategies to counteract it. To overcome these evolving barriers, the field has transitioned from traditional empirical optimization to multidimensional rational design. Moving beyond conventional structure–activity relationship (SAR)-guided chemical synthesis, current approaches integrate diverse innovative methodologies. Based on these advances, this review provides the first systematic summary of contemporary strategies for developing novel LPs, offering new perspectives and methodological support to combat resistant bacterial infections and accelerate the development of next-generation LP-based therapeutics. Full article

(This article belongs to the Section Antimicrobial Peptides)

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22 pages, 10038 KB

Open AccessArticle

Genomic Evidence Supporting a One Health Perspective on Staphylococcus aureus Bovine Mastitis

by Gabriele Meroni, Valerio Massimo Sora, Giulia Laterza, Alessio Soggiu, Piera Anna Martino, Francesca Zaghen, Luigi Bonizzi, Luciana Colombo and Alfonso Zecconi

Antibiotics 2026, 15(1), 98; https://doi.org/10.3390/antibiotics15010098 - 18 Jan 2026

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Abstract

Background/Objectives: Staphylococcus aureus is a multifaceted pathogen responsible for diseases in humans and in several animal species, including dairy cows. This study aimed to characterize and compare the genetic diversity, lineage distribution, and antimicrobial resistance profiles of S. aureus isolates from bovine [...] Read more.

Background/Objectives: Staphylococcus aureus is a multifaceted pathogen responsible for diseases in humans and in several animal species, including dairy cows. This study aimed to characterize and compare the genetic diversity, lineage distribution, and antimicrobial resistance profiles of S. aureus isolates from bovine milk with human-derived reference genomes to investigate host adaptation and inter-species transmission. Methods: Genomic analyses were performed on S. aureus isolates from quarter milk samples of dairy cows together with human-derived sequences from public databases. Whole-genome sequencing and multi-locus sequence typing (MLST) were used to determine sequence type (ST) distribution, and the presence of key antibiotic resistance genes and mobile genetic elements (MGEs) was assessed. Comparative genomics was applied to evaluate gene content, phylogenetic relationships, and lineage–host associations. Results: The dataset encompassed bovine-adapted lineages (CC97, CC133, CC151) and human-associated lineages (CC1, CC5, CC8, CC30, CC45), as well as livestock-associated ST398 in bovine samples and human-adapted ST5 and ST6 in animals. ST8 was the only ST shared between animal and human isolates and showed differing resistance profiles, with animal ST8 carrying resistance determinants absent from human ST8. Bovine-adapted strains were characterized by recurrent loss of human-associated virulence genes and acquisition of bovine-associated mobile genetic elements, and blaZ and mecA were rarely detected in bovine-adapted CC97 but were frequently present in human CC5 and CC8. Overall, animal isolates carried fewer resistance genes than human isolates. Conclusions: S. aureus from dairy cows and humans displayed substantial genetic diversity, with evidence of host-associated lineages and dynamic changes in gene and mobile element content. These findings support the need for integrated One Health surveillance to track shared and host-adapted lineages and their antibiotic resistance determinants. Full article

(This article belongs to the Special Issue Antibiotic Resistance in a One Health Context: Bridging Environmental, Agricultural, Nutritional, Veterinary, and Clinical Perspectives)

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8 pages, 212 KB

Open AccessEditorial

Epidemiology, Clinical Microbiology and Antimicrobial Therapy: A Shared Effort Against Infectious Diseases

by Francesca Pica

Antibiotics 2026, 15(1), 97; https://doi.org/10.3390/antibiotics15010097 - 17 Jan 2026

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Abstract

The last few years have confirmed that infectious diseases are characterized not only by new emerging threats (i [...] Full article

(This article belongs to the Special Issue Epidemiology, Clinical Microbiology and Antimicrobial Therapy: A Shared Effort against Infectious Diseases)

23 pages, 2620 KB

Open AccessArticle

Secretome Profiling of Lactiplantibacillus plantarum CRL681 Predicts Potential Molecular Mechanisms Involved in the Antimicrobial Activity Against Escherichia coli O157:H7

by Ayelen Antonella Baillo, Leonardo Albarracín, Eliana Heredia Ojeda, Mariano Elean, Weichen Gong, Haruki Kitazawa, Julio Villena and Silvina Fadda

Antibiotics 2026, 15(1), 96; https://doi.org/10.3390/antibiotics15010096 - 17 Jan 2026

Viewed by 389

Abstract

Background/Objectives. Lactiplantibacillus plantarum CRL681 has previously demonstrated a strong antagonistic effect against Escherichia coli O157:H7 in food matrices; however, the molecular mechanisms underlying this activity remain poorly understood. Since initial interactions between beneficial bacteria and pathogens occur mainly at the cell surface [...] Read more.

Background/Objectives. Lactiplantibacillus plantarum CRL681 has previously demonstrated a strong antagonistic effect against Escherichia coli O157:H7 in food matrices; however, the molecular mechanisms underlying this activity remain poorly understood. Since initial interactions between beneficial bacteria and pathogens occur mainly at the cell surface and in the extracellular environment, the characterization of the bacterial secretome is essential for elucidating these mechanisms. In this study, the secretome of L. plantarum CRL681 was comprehensively characterized using an integrated in silico and in vitro approach. Methods. The exoproteome and surfaceome were analyzed by LC-MS/MS under pure culture conditions and during co-culture with E. coli O157:H7. Identified proteins were functionally annotated, classified according to subcellular localization and secretion pathways, and evaluated through protein–protein interaction network analysis. Results. A total of 275 proteins were proposed as components of the CRL681 secretome, including proteins involved in cell surface remodeling, metabolism and nutrient transport, stress response, adhesion, and genetic information processing. Co-culture with EHEC induced significant changes in the expression of proteins associated with energy metabolism, transport systems, and redox homeostasis, indicating a metabolic and physiological adaptation of L. plantarum CRL681 under competitive conditions. Notably, several peptidoglycan hydrolases, ribosomal proteins with reported antimicrobial activity, and moonlighting proteins related to adhesion were identified. Conclusions. Overall, these findings suggest that the antagonistic activity of L. plantarum CRL681 against E. coli O157:H7 would be mediated by synergistic mechanisms involving metabolic adaptation, stress resistance, surface adhesion, and the production of non-bacteriocin antimicrobial proteins, supporting its potential application as a bioprotective and functional probiotic strain. Full article

(This article belongs to the Special Issue Foodborne Pathogens: Detection, Resistance Mechanisms, and Control Strategies)

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31 pages, 2995 KB

Open AccessReview

Joining Forces Against Antibiotic Resistance in Aquaculture: The Synergism Between Natural Compounds and Antibiotics

by María Melissa Gutiérrez-Pacheco, Martina Hilda Gracia-Valenzuela, Luis Alberto Ortega-Ramirez, Francisco Javier Vázquez-Armenta, Juan Manuel Leyva, Jesús Fernando Ayala-Zavala and Andrés Francisco Chávez-Almanza

Antibiotics 2026, 15(1), 95; https://doi.org/10.3390/antibiotics15010095 - 16 Jan 2026

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Abstract

The intensification of aquaculture practices has been accompanied by an increased incidence of bacterial diseases, leading to a greater reliance on antibiotics for disease control. Consequently, the widespread and often indiscriminate use of these compounds has contributed to the emergence and dissemination of [...] Read more.

The intensification of aquaculture practices has been accompanied by an increased incidence of bacterial diseases, leading to a greater reliance on antibiotics for disease control. Consequently, the widespread and often indiscriminate use of these compounds has contributed to the emergence and dissemination of antibiotic-resistant bacteria within aquaculture systems, posing a serious threat to animal health, environmental sustainability, and public health. In this regard, research efforts have focused on developing alternative strategies to reduce antibiotic use. Natural compounds have gained particular attention due to their well-documented antimicrobial and antibiofilm activities. In this context, the combined application of antibiotics and natural compounds has emerged as a promising approach to enhance antimicrobial efficacy while potentially mitigating the development of resistance. This review synthesizes the current knowledge on antibiotic resistance in aquaculture, highlights the role of biofilm formation as a key resistance mechanism, and critically examines the potential of antibiotic–natural compound combinations against major aquaculture pathogens, with particular emphasis on bacterial growth inhibition, biofilm disruption, and virulence attenuation. Collectively, the evidence discussed underscores the potential of synergistic strategies as a sustainable tool for improving disease management in aquaculture while supporting efforts to limit antibiotic resistance. Full article

(This article belongs to the Special Issue Challenges of Antibiotic Resistance: Biofilms and Anti-Biofilm Agents)

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11 pages, 626 KB

Open AccessArticle

Knowledge and Confidence of Physician Assistant Students in Managing Patients with a Documented Penicillin Allergy

by Kayla Moody, David Weil, Sarah Jane O’Neal, Nicole Sunshine and P. Brandon Bookstaver

Antibiotics 2026, 15(1), 94; https://doi.org/10.3390/antibiotics15010094 - 16 Jan 2026

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Abstract

Objective: Physician assistants (PAs) are frequently involved in managing acute bacterial infections in patients with documented penicillin (PCN) allergies. Inappropriate antibiotic choice in patients with existing allergies may place them at undue risk. This study aimed to assess the knowledge and confidence among [...] Read more.

Objective: Physician assistants (PAs) are frequently involved in managing acute bacterial infections in patients with documented penicillin (PCN) allergies. Inappropriate antibiotic choice in patients with existing allergies may place them at undue risk. This study aimed to assess the knowledge and confidence among PA students in managing patients with documented PCN allergies. Methods: An electronic survey was distributed to enrolled students in participating PA programs in North and South Carolina. The survey tool consisted of 20 questions with 13 focused on knowledge and confidence primarily scored on a 5-point Likert scale. Data were collected and protected via the REDCap^® database. Primary objectives were knowledge of penicillin allergies and confidence in management decisions. Sufficient knowledge was considered a score of 80% or greater; adequate knowledge was considered 70% or greater on relevant assessments. Results: Overall, 406 students from 10 unique programs completed the survey. They were predominantly female (76%) with 43% in the first year of their program. The mean student knowledge score was 25.9%, and 30% of respondents achieved adequate knowledge. Respondents reported an average cross reactivity between penicillin and beta-lactams of 29% (10–63%), cefazolin 50% (24–75), ceftriaxone 29% (11–60), and carbapenems 26% (8–50). The majority of respondents (66.5%) reported high levels of confidence in managing patients with penicillin allergies. Conclusions: The study found significant discordance between PA students’ high level of confidence in assessing patients with a PCN allergy and their comparative knowledge. PA students are likely to avoid beta-lactam antibiotics when there is a documented penicillin allergy, regardless of the documented reaction or low likelihood of cross-reactivity. Further training and education will help to encourage appropriate prescribing in these high-risk patients. Full article

(This article belongs to the Special Issue Antimicrobial Prescribing, Population Use and Resistance, Impact in Global Health, 3rd Edition)

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12 pages, 2766 KB

Open AccessCase Report

Eravacycline as Salvage Therapy for Severe Intra-Abdominal Infections Caused by Multidrug-Resistant Acinetobacter baumannii: A Case Series

by Marcello Trizzino, Giulio D’Agati, Luca Pipitò, Claudia Conti, Rossella Petrantoni, Raffaella Rubino, Antonio Anastasia, Sofia Urso, Irene Ganci, Maria Cappello and Antonio Cascio

Antibiotics 2026, 15(1), 93; https://doi.org/10.3390/antibiotics15010093 - 16 Jan 2026

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Abstract

Background/Objectives: Infections due to multidrug-resistant (MDR) Acinetobacter baumannii represent a critical challenge in modern healthcare, with limited therapeutic options. Eravacycline, a novel fluorocycline antibiotic, demonstrates promising in vitro activity, but real-world clinical data for complex intra-abdominal infections (IAIs) are scarce. We present [...] Read more.

Background/Objectives: Infections due to multidrug-resistant (MDR) Acinetobacter baumannii represent a critical challenge in modern healthcare, with limited therapeutic options. Eravacycline, a novel fluorocycline antibiotic, demonstrates promising in vitro activity, but real-world clinical data for complex intra-abdominal infections (IAIs) are scarce. We present two cases of severe IAI caused by carbapenem-resistant A. baumannii (CRAB) successfully treated with eravacycline. Methods: We describe the clinical course, microbiological findings, and outcomes of two critically ill patients. Case 1 was a 75-year-old male with biliary peritonitis following an endoscopic procedure. Case 2 was a 64-year-old male with infected pancreatic walled-off necrosis. Both patients had cultures positive for CRAB and failed multiple prior antibiotic regimens. Results: In both cases, the initiation of intravenous eravacycline led to significant clinical improvement, including resolution of septic shock and defervescence. A marked reduction in inflammatory markers (C-reactive protein and procalcitonin) was observed, alongside microbiological clearance of CRAB. Eravacycline was well tolerated, with no significant adverse events. Conclusions: These case reports suggest that eravacycline can be an effective and safe salvage therapy for complex IAIs caused by CRAB, even in scenarios of partial source control. It represents a valuable addition to the antimicrobial armamentarium for managing infections caused by these extensively drug-resistant organisms. Full article

(This article belongs to the Special Issue Carbapenem-Resistant Acinetobacter baumannii: From Molecular Mechanisms to Clinical Practice)

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36 pages, 2444 KB

Open AccessReview

Burden of Bacterial Antimicrobial Resistance in Libya, 1970–2024: A Systematic Meta-Analysis with Projections to 2050

by Farag A. Bleiblo, Madiha W. El-Awamie, Nariman A. Elsharif, Muetaz M. Feetouri, Ibtihag S. Alogali, Abdelhafid A. Mohamed, Mahmoud A. Aloriby, Allaaeddin A. El Salabi, Tarek S. Bader, Souad A. Moftah, Omar S. Alqabbasi, Guma M. Abdeldaim, Eman M. Almajbry, Mohamed M. Khamid, Yousef M. Hasen, Yusra Layas, Shamsi S. Shamsi, Ali M. Milad, Abdulah D. Alamami, Ghaliah H. Elraid, Aziza S. Hamed and Aeshah A. Altajouri Show full author list Hide full author list

Antibiotics 2026, 15(1), 92; https://doi.org/10.3390/antibiotics15010092 - 16 Jan 2026

Viewed by 1403

Abstract

Background: Libya, a conflict-affected North African country, has a fragile health system and poor surveillance, leaving it largely underrepresented in global estimates. Earlier Libyan reviews were descriptive, lacking breakpoint standardization, isolate-level pooling, or AMR-attributable mortality and DALY estimates. To our knowledge, this study [...] Read more.

Background: Libya, a conflict-affected North African country, has a fragile health system and poor surveillance, leaving it largely underrepresented in global estimates. Earlier Libyan reviews were descriptive, lacking breakpoint standardization, isolate-level pooling, or AMR-attributable mortality and DALY estimates. To our knowledge, this study represents the first comprehensive report that integrates phenotypic and genotypic data to estimate deaths and DALYs attributable to AMR-induced mortality and morbidity, describe spatiotemporal patterns, and model future trajectories. Methods: We performed a meta-analysis according to the PRISMA 2020 guideline of Libyan studies reporting phenotypic or genotypic resistance among clinical bacterial isolates (1970–2024), combined with microbiology records from hospitals and national surveillance systems (preregistered in PROSPERO ID: CRD420251066018). Susceptibility results were standardized to CLSI/EUCAST and deduplicated using WHO GLASS first-isolate rules. We used random-effects meta-regression to estimate pooled resistance, and the counterfactual approach of Global Burden of Disease (GBD) was applied to estimate AMR-attributable DALYs. Molecular data on resistance genes, sequence types, and tuberculosis mutations were systematically collected. Results: We included 62 eligible studies together with national and facility-level surveillance datasets, providing isolate-level susceptibility data for 31,439 clinical isolates from Libya. In 2024, we estimated 2183 deaths (95% UI 1752–2614) attributable to AMR, representing 9.7% (95% UI 7.8–11.6) of total deaths with a mortality rate of 15.2 per 100,000 (12.2–18.2). DALYs attributable to AMR increased from 14,628 (95% UI 11,702–17,554) in 1970 to 96,715 (95% UI 77,372–116,058). The highest pooled resistance involved carbapenem-resistant/MDR A. baumannii, third-generation cephalosporin- and fluoroquinolone-resistant Enterobacterales, and carbapenem-resistant P. aeruginosa. Molecular data showed widespread ESBLs, OXA-/NDM-type carbapenemases, plasmid-mediated colistin resistance, high-risk E. coli ST131 and K. pneumoniae ST147 lineages, and canonical drug-resistant M. tuberculosis mutations. Conclusions: Combined with global and regional evidence, our findings suggest a high and increasing burden of AMR in Libya. These findings emphasize the need for rapid expansion of data collection systems, GLASS-aligned surveillance, diagnostic capacities, and infection control measures. Full article

(This article belongs to the Section Antibiotics Use and Antimicrobial Stewardship)

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16 pages, 418 KB

Open AccessArticle

Institutional Practices Drive Antibiotic Variability in Neonatal Intensive Care Units: Baseline Evidence to Inform National Stewardship Interventions in Oman

by Abdullah Alqayoudhi, Manoj Malviya, Sathiya Murthi, Mohammed Rasik NV, Adil Said Al-Wahaibi, Raya Al-Habsi, Said Al-Balushi, Talal Alwardi, Agha Hatif Shamsi, Halah Bait Raidan, Aamera Al-Majrafi, Preethi Kiran, Eyad Hani Abu Abu Alhaijaa, Kawther Al Amri, Khalfan Al Abdali, Mohammed S. Al Reesi, Nasser Al-Shafouri, Amal Al-Jabri, Sachin Shah, Said Al-Kindi, Zubair H. Aghai, Mohammed Al-Yahmadi and Amal Al-Maani Show full author list Hide full author list

Antibiotics 2026, 15(1), 91; https://doi.org/10.3390/antibiotics15010091 - 16 Jan 2026

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Abstract

Background: Antibiotic overuse in Neonatal Intensive Care Units (NICUs) is a major contributor to antimicrobial resistance and adverse neonatal outcomes. This study aims to evaluate baseline antibiotic utilization (AU), identify factors influencing variability, and assess the impact of neonatal characteristics and sepsis [...] Read more.

Background: Antibiotic overuse in Neonatal Intensive Care Units (NICUs) is a major contributor to antimicrobial resistance and adverse neonatal outcomes. This study aims to evaluate baseline antibiotic utilization (AU), identify factors influencing variability, and assess the impact of neonatal characteristics and sepsis incidence. Methods: A multicenter retrospective analysis examined AU in seven NICUs from 2019 to 2023, involving 25,532 neonatal admissions during national antibiotic stewardship program implementation. Data encompassed neonatal clinical parameters, sepsis incidence, and AU metrics, including days of therapy (DOT) per 1000 patient-days. Statistical analyses included correlation assessments and multivariate regression to identify determinants of antibiotic use. Results: Overall, 43.8% of neonates received antimicrobials, with individual NICUs ranging from 24% to 73% (p < 0.001). Antimicrobial-exposed neonates had a mean gestational age of 35.1 weeks [SD ± 4.4] and a mean birth weight of 2360 g [SD ± 970]. Antimicrobial-exposed neonates were generally more premature [35.1 (±4.4) weeks vs. 37.5 (±2.5) weeks (p < 0.001)] and had lower mean birth weight [2360 g (±971) vs. 2817 g (±686) (p < 0.001)] compared to those not exposed to antimicrobials. Total antimicrobial days varied markedly (8761 to 37,683 days), with DOT per 1000 patient-days ranging from 322 to 1031. Antimicrobial use for culture-negative sepsis varied widely among centers, from 23% to 73%. Antimicrobial-exposed neonates had higher all-cause mortality compared to those who did not [(7.5% vs. 3.2%), (p < 0.001)]. Multivariate analysis revealed individual NICU practice patterns remained significant predictors after adjusting for neonatal characteristics. Conclusions: Neonatal antimicrobial use varied significantly among NICUs, driven primarily by institutional practices rather than neonatal demographics. These findings provide nationally representative baseline data to inform neonatal antimicrobial stewardship interventions and offer transferable lessons for other countries seeking to optimize antibiotic use in NICUs amid rising global antimicrobial resistance. Full article

(This article belongs to the Section Antibiotics Use and Antimicrobial Stewardship)

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14 pages, 1058 KB

Open AccessArticle

Clinical Outcomes of Bloodstream Infections in Liver Transplant Recipients: A Ten-Year Single-Center Retrospective Analysis, from Türkiye

by Selda Aydin, Meyha Sahin, Bahadir Ceylan, Tunahan Abali, Safa Arda Akin, Murat Dayangac and Ali Mert

Antibiotics 2026, 15(1), 90; https://doi.org/10.3390/antibiotics15010090 - 16 Jan 2026

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Abstract

Background/Objectives: Infections remain a leading cause of morbidity and mortality following liver transplantation, with bloodstream infections (BSIs) representing one of the most critical complications. This study aimed to identify factors associated with mortality in liver transplant recipients who developed BSIs over a [...] Read more.

Background/Objectives: Infections remain a leading cause of morbidity and mortality following liver transplantation, with bloodstream infections (BSIs) representing one of the most critical complications. This study aimed to identify factors associated with mortality in liver transplant recipients who developed BSIs over a 10-year period. Methods: This retrospective study was conducted at a tertiary university hospital between 1 April 2014 and 31 December 2024. A total of 467 adult patients underwent liver transplantation during the study period. Among 467 patients, a total of 210 bloodstream infection episodes occurring in 136 patients were included in the study. Results: BSIs occurred in 29.1% (136/467) of patients, with a total of 210 episodes. The median age was 55 years (IQR: 45–63). Most transplants (95.2%) were from living donors. Hepatitis B virus infection (27.1%) was the most common underlying etiology of cirrhosis. The majority of BSIs (61.2%) occurred within the first three months post-transplant. A total of 242 pathogens were isolated, with ESBL-producing Enterobacterales identified in 72.6% and carbapenem-resistant Enterobacterales (CRE) in 30.1% of cases. Notably, carbapenem resistance among Klebsiella spp. was high at 51.78%. The overall mortality rate was 14.28%. Multivariate analysis identified that a high Pitt Bacteremia Score (hazard ratio [HR] 1.502, 95% confidence interval [CI] 1.361–1.657, p < 0.001) and CRE infection (HR 3.644, 95% CI 1.380–9.620, p = 0.009) were independent predictors of mortality. Conclusions: BSIs are a significant post-transplant complication with high antimicrobial resistance. The Pitt bacteremia score is a strong predictor of mortality and may guide early risk stratification and clinical management in liver transplant recipients. Full article

(This article belongs to the Special Issue Multidrug-Resistant Gram-Negative Bacteria Infections: Current Epidemiology, Prognosis and Treatment Options)

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21 pages, 811 KB

Open AccessArticle

Policy Framework and Barriers in Antimicrobial Consumption Monitoring at the National Level: A Qualitative Study from Pakistan

by Beenish Ihsan, Shahid Muhammad Iqbal, Mohammed Aufy and QurratulAin Jamil

Antibiotics 2026, 15(1), 89; https://doi.org/10.3390/antibiotics15010089 - 15 Jan 2026

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Abstract

Objectives: The study aims to assess the strategies used to estimate antimicrobial consumption (AMC) and the barriers encountered in data collection. It also addresses the perception about AMC based on the World Health Organization (WHO) definition. Methodology: The qualitative study adhered to the [...] Read more.

Objectives: The study aims to assess the strategies used to estimate antimicrobial consumption (AMC) and the barriers encountered in data collection. It also addresses the perception about AMC based on the World Health Organization (WHO) definition. Methodology: The qualitative study adhered to the standard consolidated criteria for reporting qualitative studies (COREQ) guidelines. It involved stakeholders from diverse sectors, i.e., regulatory bodies, the pharmaceutical industry, international health organizations, policy experts, medical professionals, veterinary doctors, and academia (nursing, medicine, and pharmacy). A total of 37 in-depth interviews were conducted using a semi-structured interview schema. The interviews were recorded and transcribed verbatim. Codes were generated afterward and organized into themes. Results: Data analysis yielded five themes consisting of (i) Perception about Antimicrobial Consumption, AWaRe (Access, Watch, Reserve) classification and related terms, (ii) Antimicrobial Consumption: Policy Design, (iii) Data management and record keeping for the Estimation of Antimicrobial Consumption, (iv) Levels of Estimation for Antimicrobial consumption and Organizations, and (v) Challenges and suggested solutions in estimation of AMC: One health approach is the way forward. Conclusions: The study concluded that AMC and AMR are two sides of the same coin. The solution to AMR and excessive AMC is to re-evaluate the policy and implement legislation strictly. Efforts focused on irrational prescribing and unsupervised OTC sales of antimicrobials. This will help in reducing the consumption of broad-spectrum antimicrobials. Full article

(This article belongs to the Special Issue Global Strategies for Antimicrobial Surveillance: Country, Regional and Global Perspectives)

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14 pages, 653 KB

Open AccessEditor’s ChoiceArticle

Impact of High-Dose Cefepime During the Initial 48 h on Intensive Care Unit Survival in Sepsis: A Retrospective Observational Study

by Tsukasa Kuwana, Kosaku Kinoshita, Yuma Kanai, Yurina Yamaya, Ken Takahashi, Satoshi Ishizuka and Toru Imai

Antibiotics 2026, 15(1), 88; https://doi.org/10.3390/antibiotics15010088 - 15 Jan 2026

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Abstract

Background/Objectives: Sepsis is a life-threatening condition associated with high mortality. Optimal dosing strategies for β-lactam antibiotics in sepsis remain controversial, particularly in patients with renal impairment. Cefepime (CFPM) is widely used as empiric therapy; however, its appropriate initial dosing in critically ill patients [...] Read more.

Background/Objectives: Sepsis is a life-threatening condition associated with high mortality. Optimal dosing strategies for β-lactam antibiotics in sepsis remain controversial, particularly in patients with renal impairment. Cefepime (CFPM) is widely used as empiric therapy; however, its appropriate initial dosing in critically ill patients is unclear. This study aimed to evaluate whether high-dose CFPM administration during the first 48 h improves survival in patients with sepsis, irrespective of renal function. Methods: This single-center, retrospective, observational study included adult intensive care unit (ICU) patients with sepsis who received CFPM as initial therapy between January 2017 and December 2024. Patients were categorized into High-dose (12 g within 48 h; 2 g every 8 h) and Low-dose (<12 g/48 h) groups. The primary outcome was ICU survival. To address confounding, inverse probability of treatment weighting (IPTW) based on serum creatinine was applied, with sensitivity analyses using 1% trimmed and stabilized IPTW. Results: Of 122 eligible patients, 84 were analyzed (High-dose: n = 27; Low-dose: n = 57). After IPTW adjustment, high-dose CFPM was significantly associated with improved ICU survival (odds ratio [OR] 5.43, 95% confidence interval [CI] 1.60–18.39, p = 0.0066). This association remained consistent in the 1% trimmed IPTW analysis (OR 4.07, 95% CI 1.19–13.97, p = 0.0256). Stabilized IPTW yielded a similar effect estimate, though without statistical significance (OR 5.43, 95% CI 0.72–41.16, p = 0.1017). Overall, results were consistent in direction and magnitude across models. Conclusions: High-dose CFPM administration during the initial 48 h was associated with improved ICU survival in patients with sepsis, independent of renal function. Full article

(This article belongs to the Special Issue Antibiotic Stewardship and Infection Control Strategies in Critical Care)

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19 pages, 1546 KB

Open AccessSystematic Review

Antimicrobial Resistance in Selected Foodborne Pathogens in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

by Kedir A. Hassen, Jose Fafetine, Laurinda Augusto, Inacio Mandomando, Marcelino Garrine and Gudeta W. Sileshi

Antibiotics 2026, 15(1), 87; https://doi.org/10.3390/antibiotics15010087 - 15 Jan 2026

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Abstract

Background/Objectives: The increasing trend of foodborne zoonotic pathogens exhibiting antimicrobial resistance (AMR) represents a growing threat to food safety and public health in sub-Saharan Africa (SSA). Resistant strains of foodborne zoonotic pathogens compromise treatment efficacy, raise illness, and threaten sustainable food systems in [...] Read more.

Background/Objectives: The increasing trend of foodborne zoonotic pathogens exhibiting antimicrobial resistance (AMR) represents a growing threat to food safety and public health in sub-Saharan Africa (SSA). Resistant strains of foodborne zoonotic pathogens compromise treatment efficacy, raise illness, and threaten sustainable food systems in human and animal health. However, regional understanding and policy response are limited due to the fragmentation of data and the inadequacy of surveillance. This systematic review and meta-analysis aimed to achieve the following: (1) estimate the pooled prevalence of AMR, including multidrug resistance (MDR) in selected foodborne pathogens; (2) compare subgroup variations across countries, pathogen species, and antibiotic classes; and (3) evaluate temporal trends. Methods: Following PRISMA 2020 guidelines, studies published between 2010 and June 2025 reporting AMR and MDR in Salmonella, Campylobacter, or E. coli from food or animal sources in SSA were systematically reviewed. Data on pathogen prevalence, AMR profile, and MDR were extracted. Random-effects meta-analysis using R software was implemented to estimate the pooled prevalence and the 95% confidence intervals (95% CI). Subgroup analyses were performed to explore heterogeneity across countries, antibiotic class, and bacterial species. Results: Ninety studies from 16 sub-Saharan African countries were included, encompassing 104,086 positive isolates. The pooled foodborne pathogen prevalence was 53.1% (95% CI: 51.5–54.7), AMR prevalence was 61.6% (95% CI: 59.4–63.9), and MDR prevalence was 9.1% (95% CI: 8.3–10.0). The highest resistance was reported in Campylobacter spp. (43.6%), followed by Salmonella spp. (29.1%) and E. coli (22.8%). High heterogeneity was observed across studies (I² = 95–99%, p < 0.001). Conclusions: It is concluded that substantial AMR burden exists in food systems, highlighting an urgent need for integrated One Health surveillance, antimicrobial stewardship, and policy harmonization in SSA. Strengthening laboratory capacity, enforcing prudent antimicrobial use, and promoting regional data sharing are critical for the management of antimicrobial resistance in sub-Saharan Africa. Full article

(This article belongs to the Section Antibiotics Use and Antimicrobial Stewardship)

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19 pages, 1992 KB

Open AccessArticle

Antimicrobial Use and Epidemiological Resistance Profiles of Commensal Escherichia coli from Swine Farms in Córdoba, Argentina

by Nicolás Javier Litterio, María del Pilar Zarazaga, Augusto Matías Lorenzutti, Juan Pablo Vico, Martín Alejandro Himelfarb, Mariano Guillermo Tinti, Ana Paola Zogbi, Sonia Rubio-Langre and Manuel Ignacio San Andrés Larrea

Antibiotics 2026, 15(1), 86; https://doi.org/10.3390/antibiotics15010086 - 15 Jan 2026

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Abstract

Background/Objectives: The expansion of intensive swine production in Córdoba, Argentina, underscores the need to assess the risks associated with antimicrobial (AM) use, whose extensive application has driven antimicrobial resistance, a major global threat within the One Health framework. This study aimed to characterize [...] Read more.

Background/Objectives: The expansion of intensive swine production in Córdoba, Argentina, underscores the need to assess the risks associated with antimicrobial (AM) use, whose extensive application has driven antimicrobial resistance, a major global threat within the One Health framework. This study aimed to characterize AM use practices and evaluate the epidemiological resistance profiles (non-wild-type phenotypes, NWT) of commensal Escherichia coli of fecal origin from swine farms, using epidemiological cut-off values (ECOFFs) as a surveillance criterion. Methods: An observational cross-sectional study was conducted in 19 farrow-to-finish farms in Córdoba during 2023. Information on AM use (prophylaxis, metaphylaxis, treatment) across production categories was collected. A total of 437 E. coli isolates were obtained from fecal samples, and minimum inhibitory concentrations (MICs) were determined for 10 AMs of critical importance for human and animal health. NWT phenotypes were classified according to EUCAST ECOFFs, and multidrug resistance (MDR) was assessed. Results: AM use was frequent and predominantly prophylactic (89.5% of farms), mainly through mass medication (66.3%), with macrolides and amoxicillin being the most commonly administered AMs. NWT proportions were extremely high (90–92%) for ampicillin, tetracyclines, and chloramphenicol and substantial for ciprofloxacin (50.6%), sulfamethoxazole (68.2%), and trimethoprim (44.9%). Extended-spectrum β-lactamase (ESBL)-producing phenotypes were detected. Alarmingly, 92% of isolates were classified as MDR E. coli, with homogeneous distribution across production categories. Conclusions: Findings reveal intensive and largely empirical AM use that has consolidated a stable intestinal resistome in the swine population. High MDR levels, even in categories with limited direct AM exposure or involving banned compounds, suggest that co-selection and horizontal gene transfer are key drivers of resistance. This scenario highlights the urgent need to strengthen integrated surveillance and promote prudent AM use strategies under the One Health approach to preserve therapeutic efficacy. Full article

(This article belongs to the Special Issue Antimicrobial Resistance in Veterinary Science, 2nd Edition)

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10 pages, 447 KB

Open AccessArticle

An Unexpected Inverse Relationship Between Biofilm Formation and Antibiotic Resistance in Stenotrophomonas maltophilia

by Arianna Pompilio and Giovanni Di Bonaventura

Antibiotics 2026, 15(1), 85; https://doi.org/10.3390/antibiotics15010085 - 15 Jan 2026

Viewed by 312

Abstract

Background/Objectives: Stenotrophomonas maltophilia is an opportunistic pathogen causing severe infections, particularly in patients with cystic fibrosis (CF). Its intrinsic multidrug resistance and biofilm-forming capacity complicate treatment. Although biofilms are generally associated with antimicrobial tolerance, the relationship between biofilm formation and planktonic antibiotic [...] Read more.

Background/Objectives: Stenotrophomonas maltophilia is an opportunistic pathogen causing severe infections, particularly in patients with cystic fibrosis (CF). Its intrinsic multidrug resistance and biofilm-forming capacity complicate treatment. Although biofilms are generally associated with antimicrobial tolerance, the relationship between biofilm formation and planktonic antibiotic resistance in S. maltophilia remains poorly understood. This study investigated the association between antibiotic resistance profiles and biofilm production in clinical isolates from CF and non-CF patients. Methods: A total of 86 clinical isolates (40 from CF airways and 46 from non-CF patients) were analyzed. Susceptibility to seven antibiotics was assessed by disk diffusion, and multidrug resistance profiles were defined using standard criteria. Biofilm formation was quantified after 24 h using a crystal violet microtiter plate assay and categorized by using a semiquantitative scale. Results: High resistance rates were observed, particularly to meropenem (87.2%), ciprofloxacin (80.2%), and rifampicin (72.1%). CF isolates exhibited significantly higher resistance to piperacillin/tazobactam and a greater prevalence of multidrug resistance. Biofilm formation was detected in 94.2% of isolates, with strong or powerful producers predominating. However, CF isolates formed significantly less biofilm than non-CF isolates. Notably, resistance to piperacillin/tazobactam and meropenem was associated with reduced biofilm biomass and a lower proportion of high biofilm producers. Across all isolates, an inverse correlation was observed between the number of antibiotic resistances and biofilm biomass. These trends persisted after stratification by clinical origin, although some comparisons did not reach statistical significance. Conclusions: This study reveals an unexpected inverse relationship between planktonic antibiotic resistance and biofilm-forming capacity in S. maltophilia. Enhanced biofilm production may represent an alternative persistence strategy in more antibiotic-susceptible strains, with important implications for infection management and therapeutic failure. Full article

(This article belongs to the Special Issue Antibiotic Resistance and Virulence Mechanisms in Gram-Negative Bacteria: An Alliance for Success)

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20 pages, 1167 KB

Open AccessReview

One Health Perspective on Antimicrobial Resistance in Bovine Mastitis Pathogens—A Narrative Review

by Bigya Dhital, Rameshwor Pudasaini, Jui-Chun Hsieh, Ramchandra Pudasaini, Ying-Tsong Chen, Day-Yu Chao and Hsin-I Chiang

Antibiotics 2026, 15(1), 84; https://doi.org/10.3390/antibiotics15010084 - 14 Jan 2026

Viewed by 1204

Abstract

Background/Objectives: Bovine mastitis, a significant global concern in dairy farming, results in substantial economic losses and poses considerable risks to both animal and human health. With the increasing prevalence of antimicrobial resistance (AMR) in mastitis pathogens, the potential for resistant infections to [...] Read more.

Background/Objectives: Bovine mastitis, a significant global concern in dairy farming, results in substantial economic losses and poses considerable risks to both animal and human health. With the increasing prevalence of antimicrobial resistance (AMR) in mastitis pathogens, the potential for resistant infections to spread from livestock to humans and the environment is becoming a critical public health issue. This narrative review summarizes the current evidence on antimicrobial resistance in pathogens causing bovine mastitis and examines it from a One Health perspective, encompassing animal, human, and environmental interfaces. Results: By examining the complex interplay among animal, human, and environmental health, we highlight key factors that drive resistance, including the overuse of antimicrobials, poor farm management, and environmental contamination. We also discuss innovative strategies, such as enhanced surveillance, pathogen-specific diagnostics, alternatives to antimicrobials, and sustainable farm practices, that can mitigate the emergence of resistance. Key knowledge gaps include a limited understanding of antimicrobial residues, resistant pathogens, and gene transmission pathways and inconsistent implementation of antimicrobial stewardship practices. Conclusions: This review emphasizes the need for a coordinated, multidisciplinary effort to reduce the burden of AMR in bovine mastitis pathogens, ensuring the continued efficacy of antimicrobials and safeguarding public health through responsible management and policy interventions. Full article

(This article belongs to the Section The Global Need for Effective Antibiotics)

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20 pages, 14008 KB

Open AccessArticle

The Antimicrobial Peptide CRAMP-34 Eradicates Escherichia coli Biofilms by Interfering with the kduD-Dependent Network

by Hongzao Yang, Jing Xiong, Sisi Su, Zhuo Yang, Wu Yang, Lianci Peng, Suhui Zhang, Jinjie Qiu, Yuzhang He and Hongwei Chen

Antibiotics 2026, 15(1), 83; https://doi.org/10.3390/antibiotics15010083 - 14 Jan 2026

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Abstract

Background/Objectives: Bacterial biofilms formed by Escherichia coli pose a significant challenge in veterinary medicine due to their intrinsic resistance to antibiotics. Antimicrobial peptides (AMPs) represent a promising alternative. AMPs exert their bactericidal activity by binding to negatively charged phospholipids in bacterial membranes [...] Read more.

Background/Objectives: Bacterial biofilms formed by Escherichia coli pose a significant challenge in veterinary medicine due to their intrinsic resistance to antibiotics. Antimicrobial peptides (AMPs) represent a promising alternative. AMPs exert their bactericidal activity by binding to negatively charged phospholipids in bacterial membranes via electrostatic interactions, leading to membrane disruption and rapid cell lysis. Methods: In vitro assays including MIC determination, biofilm eradication testing (crystal violet, colony counts, and CLSM), swimming motility, and EPS quantification were performed. CRISPR/Cas9 was used to construct and complement a kduD mutant. A transposon mutagenesis library was screened for biofilm-defective mutants. In an in vivo murine excisional wound infection model treated with the mouse cathelicidin-related antimicrobial peptide (CRAMP-34), wound closure and bacterial burden were monitored. Gene expression changes were analyzed via RT-qPCR. Results: CRAMP-34 effectively eradicated pre-formed biofilms of a clinically relevant, porcine-origin E. coli strain and promoted wound healing in the murine infection model. We conducted a genome-wide transposon mutagenesis screen, which identified kduD as a critical gene for robust biofilm formation. Functional characterization revealed that kduD deletion drastically impairs flagellar motility and alters exopolysaccharide production, leading to defective biofilm architecture without affecting growth. Notably, the anti-biofilm activity of CRAMP-34 phenocopied aspects of the kduD deletion, including motility inhibition and transcriptional repression of a common set of biofilm-related genes. Conclusions: This research highlights CRAMP-34 as a potent anti-biofilm agent and unveils kduD as a previously unrecognized regulator of E. coli biofilm development, which is also targeted by CRAMP-34. Full article

(This article belongs to the Special Issue Antimicrobial Resistance in Biofilm-Associated Infections)

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14 pages, 471 KB

Open AccessReview

Antimicrobial Resistance: How Can We Overcome the Problem?

by Valerio Massimo Sora, Clementine Wallet, Gabriele Meroni, Thomas Loustau, Olivier Rohr, Alfonso Zecconi and Christian Schwartz

Antibiotics 2026, 15(1), 82; https://doi.org/10.3390/antibiotics15010082 - 14 Jan 2026

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Abstract

Antimicrobials are common drugs used to treat and prevent infectious diseases in plants, animals, and humans. Since their discovery in the mid-20th century, their use has dramatically increased for the benefit of humanity, and also for animal care. However, antimicrobial resistance soon appeared, [...] Read more.

Antimicrobials are common drugs used to treat and prevent infectious diseases in plants, animals, and humans. Since their discovery in the mid-20th century, their use has dramatically increased for the benefit of humanity, and also for animal care. However, antimicrobial resistance soon appeared, which, according to the WHO, will limit or impede their use at the horizon of 2050. Indeed, antimicrobial resistance (AMR), which is a natural phenomenon in bacteria increased dramatically over the last 3 decades mainly due to the overuse and misuse of antibiotics in humans, animals, and plants. Apart from affecting human health, drug-resistant diseases also adversely affect plant and animal health, reduce agricultural productivity, and threaten food security. AMR affects all countries, regardless of economic status, and imposes high costs on health systems and national economies. Therefore, antimicrobial resistance should be studied and analyzed under the One Health paradigm. In mind of the One Health paradigm, to reduce and overcome AMR, we must take at least 3 complementary and integrated actions: (i) monitoring the resistome; (ii) developing protective strategies against antibiotic resistance; (iii) taking curative actions by designing new and original treatments. Moreover, the three actions must be conducted simultaneously due to the continuous adaptation of bacteria. Full article

(This article belongs to the Special Issue The One Health Action Plan Against Antimicrobial Resistance)

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