Antibiotics

16 pages, 833 KB

Open AccessArticle

In Vitro Synergistic Effects of Antibiotic Combinations Against Multidrug-Resistant Streptococcus suis from Diseased Pigs

by Wiyada Chumpol, Kamonwan Lunha, Surasak Jiemsup and Suganya Yongkiettrakul

Antibiotics 2026, 15(2), 136; https://doi.org/10.3390/antibiotics15020136 - 29 Jan 2026

Abstract

Background/Objectives: Multidrug-resistant (MDR) strains of Streptococcus suis are increasingly prevalent and present significant challenges in clinical management. Given that the development of new antibiotics is a resource-intensive process and time-consuming, there is an urgent need for alternative therapeutic strategies to address resistance in [...] Read more.

Background/Objectives: Multidrug-resistant (MDR) strains of Streptococcus suis are increasingly prevalent and present significant challenges in clinical management. Given that the development of new antibiotics is a resource-intensive process and time-consuming, there is an urgent need for alternative therapeutic strategies to address resistance in the short term. One promising approach is the use of combination therapy, which involves pairing potent antibiotics with agents that may be less effective on their own, to enhance therapeutic efficacy and potentially overcome resistance mechanisms. This study aimed to investigate the in vitro antibacterial activity of combining two classes of antibiotics with distinct mechanisms of action—cell wall synthesis inhibitors and protein synthesis inhibitors—against MDR S. suis strains isolated from diseased pigs. Methods: A total of 36 MDR S. suis strains were tested using a microbroth dilution checkerboard assay to determine the minimum inhibitory concentration (MIC) of four cell wall synthesis inhibitors —amoxicillin/clavulanic acid (AMC), ampicillin (AMP), penicillin G (PEN), and vancomycin (VAN)— in combination with four protein synthesis inhibitors —gentamicin (GEN), neomycin (NEO), tilmicosin (TMS), and tylosin (TYL). Time–kill curve assays were conducted to evaluate the in vitro bactericidal activity of synergistic antibiotic combinations (PEN–GEN and AMP–NEO) against Beta-lactam-resistant and Beta-lactam-susceptible MDR S. suis strains. Results: Checkerboard analysis revealed that penicillin-gentamicin combination exhibited the most effective synergistic activity against the MDR S. suis strains (10/19, 52.6%), with ∑FIC values of 0.25–1.06 and MIC reductions from resistant to susceptible levels. Time-kill assays further confirmed the synergistic bactericidal effect of the combination, demonstrating complete bacterial clearance within 6–9 h, markedly rapid bacterial killing compared to monotherapy. Conclusions: This study demonstrates that antibiotic combinations, particularly Beta-lactams combined with aminoglycosides, show synergistic activity against pig-isolated S. suis MDR strains. The PEN-GEN combination exhibited strong synergistic and bactericidal effects, supporting combination therapy as a potential strategy to address antimicrobial resistance. Further evaluation in diverse strain backgrounds and prudent antibiotic use are essential to confirm efficacy and limit the emergence of antibiotic resistance. Full article

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27 pages, 3694 KB

Open AccessArticle

Whole-Genome Sequence Analysis of Colistin-Resistant, mcr-Harboring Escherichia coli Isolated from a Swine Slaughterhouse in Thailand

by Ratchadaporn Boripun, Pakpoom Tadee, Ravisa Warin, Naparat Suttidate, Doan Hoang Phu, Hidenori Kabeya, Chaithep Poolkhet, Sumalee Boonmar, Suchawadee Tesakul, Yanika Klainiem and Nuttapong Pavana

Antibiotics 2026, 15(2), 135; https://doi.org/10.3390/antibiotics15020135 - 29 Jan 2026

Abstract

The emergence of colistin-resistant Escherichia coli (E. coli) in livestock poses a major public health concern due to its zoonotic potential and multidrug resistance (MDR). The study aimed to detect mobilized colistin resistance genes (mcr-1 to mcr-9) in E. [...] Read more.

The emergence of colistin-resistant Escherichia coli (E. coli) in livestock poses a major public health concern due to its zoonotic potential and multidrug resistance (MDR). The study aimed to detect mobilized colistin resistance genes (mcr-1 to mcr-9) in E. coli isolates, along with characterizing their antimicrobial susceptibility, resistance genes, virulence genes, and whole genome sequencing. We investigated E. coli contamination in a swine slaughterhouse in Nakhon Si Thammarat Province, Thailand. A total of 200 fecal samples were collected and screened for E. coli using selective media supplemented with colistin. A total of 200 fecal samples were collected from a swine slaughterhouse and screened for E. coli using selective media supplemented with colistin. Presumptive E. coli isolates were confirmed by PCR, followed by molecular detection of mcr-1 to mcr-9 genes. Antimicrobial susceptibility testing was performed using the disk diffusion method. Selected isolates were further analyzed for additional antimicrobial resistance genes and virulence associated genes by PCR. Whole genome sequencing was conducted on representative isolates exhibiting high levels of antimicrobial resistance. Our results showed that out of 200 fecal samples, 124 presumptive E. coli isolates were recovered from a swine slaughterhouse using selective media containing colistin. PCR confirmation identified 112 isolates (90.32%) as E. coli. Molecular detection of mobilized colistin resistance (mcr) genes (82 isolates, 73.21%) demonstrated that mcr-1 (50.89%) was the most prevalent, followed by mcr-9 (25.89%) and mcr-3 (24.11%). Overall, the 82 mcr E. coli isolates showed the highest level of resistance to ampicillin (97.56%), followed by tetracycline (95.12%), piperacillin (73.17%), and chloramphenicol (65.85%). For non-mcr E. coli isolates, the highest resistance percentage was observed for ampicillin (96.67%), followed by piperacillin (80%) and tetracycline (73.33%). Among the isolates, 75% exhibited MDR phenotypes, showing 22 distinct resistance profiles. The most common MDR pattern was AMP-PIP-TE-C-S (12.5%). Additional antimicrobial resistance genes, including aadA, ampC, and bla_TEM, were detected in over 60% of a subset of 30 tested isolates. The virulence gene analysis revealed that eae (74.10%), associated with enteropathogenic E. coli (EPEC), was the predominant pathotype. Whole genome sequencing of five selected isolates confirmed the presence of multiple antimicrobial resistance and virulence determinants. In conclusion, this study reveals a high prevalence of MDR E. coli harboring colistin resistance genes (mcr-1 to mcr-9) in a swine slaughterhouse in southern Thailand. The findings highlight the potential risk of zoonotic transmission of antimicrobial resistant E. coli through the food production chain and emphasize the importance of continuous genomic surveillance and prudent antimicrobial use in livestock production systems. Full article

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

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14 pages, 632 KB

Open AccessArticle

Should Preoperative Biliary Decontamination Be Considered to Minimize Morbidity and Mortality Following Pancreatoduodenectomy?

by Natalia Olszewska, Tomasz Guzel, Agnieszka Milner, Piotr Paluszkiewicz, Edyta Podsiadły and Maciej Słodkowski

Antibiotics 2026, 15(2), 134; https://doi.org/10.3390/antibiotics15020134 - 29 Jan 2026

Abstract

Background: Pancreatoduodenectomy (PD) remains the fundamental treatment for periampullary malignancies but is associated with considerable morbidity (20–50%) and mortality (2–7%). Bacteriobilia contributes to unfavourable postoperative outcomes. Current antibiotic prophylaxis recommendations endorse first-generation cephalosporins, which often fail to adequately target pathogens most frequently isolated [...] Read more.

Background: Pancreatoduodenectomy (PD) remains the fundamental treatment for periampullary malignancies but is associated with considerable morbidity (20–50%) and mortality (2–7%). Bacteriobilia contributes to unfavourable postoperative outcomes. Current antibiotic prophylaxis recommendations endorse first-generation cephalosporins, which often fail to adequately target pathogens most frequently isolated from bile. To date, no specific guidelines for preoperative targeted antibiotic therapy have been established, although tailoring such strategies to the bile microbiome may improve surgical outcomes. This study aimed to characterize bile microbiology in patients undergoing PD for pancreatic ductal adenocarcinoma (PDAC), evaluating potential antibiotherapy regimens that provide effective coverage against the most frequently isolated pathogens. Methods: A retrospective cohort analysis of 725 patients surgically treated for pancreatic tumours at a high-volume pancreatic surgery center between 2017 and 2022 was performed. To minimize heterogeneity, study was restricted to 138 patients who underwent PD with histopathological confirmed PDAC. Intraoperative bile cultures were assessed. Results: Patients with bacteriobilia likewise experienced worse outcomes: higher 5-year mortality (OR 3.01, p = 0.007), greater overall postoperative pancreatic fistula (POPF) occurrence (OR 2.54, p = 0.044) and wound infections (OR 2.90, p = 0.038). Among bile microbiome the highest susceptibility rates were observed for combination of amoxicillin/clavulanic acid with gentamicin, while the lowest were noted for cephalosporin–metronidazole regimen (93.6% vs. 30.2%, respectively). Conclusions: Bacteriobilia contributes to postoperative complications and serves as a predictor of poorer survival after PD. Standard perioperative antibiotic prophylaxis in PD is insufficient. Based on our findings, perioperative antibiotic therapy with amoxicillin/clavulanic acid and gentamicin combination appears to provide superior coverage and may improve postoperative morbidity and overall survival following PD. Full article

(This article belongs to the Special Issue Antimicrobial Stewardship in Surgical Infection)

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24 pages, 7280 KB

Open AccessArticle

Genomic Epidemiology of Carbapenem-Resistant Acinetobacter baumannii Isolated from Patients Admitted to Intensive Care Units in Network Hospitals in Southern Thailand

by Arnon Chukamnerd, Komwit Surachat, Rattanaruji Pomwised, Prasit Palittapongarnpim, Kamonnut Singkhamanan and Sarunyou Chusri

Antibiotics 2026, 15(2), 133; https://doi.org/10.3390/antibiotics15020133 - 28 Jan 2026

Abstract

Background/Objectives: Carbapenem-resistant Acinetobacter baumannii (CRAB) is classified as an urgent-threat pathogen because of its resistance to nearly all available antibiotics, resulting in high morbidity and mortality rates. However, data on the molecular epidemiology of CRAB isolates in southern Thailand are limited. This [...] Read more.

Background/Objectives: Carbapenem-resistant Acinetobacter baumannii (CRAB) is classified as an urgent-threat pathogen because of its resistance to nearly all available antibiotics, resulting in high morbidity and mortality rates. However, data on the molecular epidemiology of CRAB isolates in southern Thailand are limited. This study aimed to investigate the genomic epidemiology of CRAB isolates within a hospital network in lower southern Thailand. Methods: Whole-genome sequencing data of CRAB clinical isolates (n = 224) were obtained from a previous study. Additional isolates (n = 70) were included, for which genomic DNA was extracted and sequenced. In total, 294 isolates were collected from patients across seven hospitals in southern Thailand between 2019 and 2020. Their genomes were analyzed using several bioinformatic tools. Results: A high proportion of isolates were obtained from sputum samples of patients with CRAB infection or colonization. Sequence type (ST) 2 was the most frequent ST and was classified in the quadrant with high resistance and virulence. The Sankey diagram showed that ST2 was the dominant and most versatile CRAB lineage circulating across major hospitals, commonly associated with pneumonia, and that diverse resistance genes and plasmid combinations were dominated by bla_OXA-23. The core single-nucleotide polymorphism (SNP)-based phylogenetic tree revealed clades A1 (ST215), A2 (multiple STs), and B (ST2). Bloodstream, skin, and soft tissue infections were predominantly observed in clade B. Conclusions: Our analysis revealed widespread circulation of a high-risk ST2 CRAB lineage with enhanced resistance and virulence across hospital networks in the studied region, highlighting the importance of genomics-informed surveillance for controlling CRAB dissemination. Full article

(This article belongs to the Special Issue Molecular Epidemiology and Mechanisms of Carbapenem Resistance in Clinical Gram-Negative Bacteria)

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18 pages, 2226 KB

Open AccessArticle

Prevalence and Differential Plasmid Versus Chromosomal Distribution of Ribosome-Targeting Antibiotic Resistance Genes in Escherichia coli Isolates from River and Untreated Wastewater Environments

by Juan R. Medina-Sánchez, Marialena Salvatierra, Carmen Indira Espino, Alex O. Martínez-Torres, Alejandro Llanes and Jordi Querol-Audi

Antibiotics 2026, 15(2), 132; https://doi.org/10.3390/antibiotics15020132 - 28 Jan 2026

Abstract

Background/Objetives: The bacterial ribosome is a key target for several classes of antibiotics, including aminoglycosides, macrolides, tetracyclines, and amphenicols. Although resistance to these antibiotics is well documented in clinical settings, ribosome-targeting antibiotic resistance genes have received comparatively little attention in studies comprising [...] Read more.

Background/Objetives: The bacterial ribosome is a key target for several classes of antibiotics, including aminoglycosides, macrolides, tetracyclines, and amphenicols. Although resistance to these antibiotics is well documented in clinical settings, ribosome-targeting antibiotic resistance genes have received comparatively little attention in studies comprising aquatic environments, where research has primarily focused on β-lactams and fluoroquinolones. Moreover, while plasmid-mediated dissemination of resistance is well recognized, the chromosomal integration of resistance genes in Escherichia coli remains underexplored. Methods: In this study, E. coli isolates were recovered from two contaminated aquatic environments in Panama: surface water from the Juan Díaz River and influent wastewater from the Panama City wastewater treatment plant. Results: Overall, 80.8% of the isolates exhibited resistance to aminoglycosides, 37.4% to tetracycline, and 18.2% to chloramphenicol. Resistance genes against these antibiotics were identified via PCR, and their genomic location (plasmid or chromosome) was determined by whole-genome sequencing. Our results revealed a higher prevalence of plasmid-associated resistance genes in river isolates, while chromosomal integration was more frequent among wastewater isolates. Notably, ribosome-targeting antibiotic resistance genes were more frequently detected than those conferring resistance to β-lactams, quinolones, and sulfonamides together. Conclusions: These findings highlight distinct mechanisms underlying the dissemination of ribosome-targeting antibiotic resistance genes in aquatic environments, where pollutant pressure in surface waters may favor plasmid maintenance, while chromosomal integration may represent a strategy to reduce the fitness cost associated with plasmid carriage and ensure stable resistance persistence. Full article

(This article belongs to the Special Issue Genomic Analysis of Antimicrobial Drug-Resistant Bacteria)

18 pages, 337 KB

Open AccessArticle

Phenotypic and Genomic Characterization of Vancomycin Non-Susceptibility in Multidrug-Resistant Enterococcus spp. From Hungarian Poultry

by Ádám Kerek, Gergely Tornyos, Krisztián Bányai, Eszter Kaszab and Ákos Jerzsele

Antibiotics 2026, 15(2), 131; https://doi.org/10.3390/antibiotics15020131 - 28 Jan 2026

Abstract

Background: Vancomycin is a critically important antimicrobial in human medicine, and vancomycin-non-susceptible enterococci represent a One Health concern when animal reservoirs contribute to the wider resistance ecology. We aimed to characterize vancomycin non-susceptibility among poultry-derived Enterococcus spp. from Hungary, using a combined [...] Read more.

Background: Vancomycin is a critically important antimicrobial in human medicine, and vancomycin-non-susceptible enterococci represent a One Health concern when animal reservoirs contribute to the wider resistance ecology. We aimed to characterize vancomycin non-susceptibility among poultry-derived Enterococcus spp. from Hungary, using a combined phenotypic–genomic approach. Methods: Following a phenotypic pre-screen with antimicrobials authorized for poultry, 218 isolates with elevated minimum inhibitory concentrations (MICs) were selected for extended broth microdilution testing including vancomycin. Vancomycin susceptibility was interpreted using Clinical and Laboratory Standards Institute (CLSI) clinical breakpoints and European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cut-off values (ECOFFs). Whole-genome sequencing was performed on a targeted multidrug resistant (MDR) subset (n = 42), enriched for elevated or borderline vancomycin MICs and stratified by region and host species (chicken, turkey), and resistance determinants were annotated against the Comprehensive Antibiotic Resistance Database (CARD) using stringent similarity/coverage thresholds. Results: Among the 218 pre-screened isolates (126 from chickens; 92 from turkeys), 196 (89.9%) met MDR criteria. For vancomycin, 15.6% of isolates were resistant and 9.2% intermediate by CLSI, while EUCAST ECOFF classification placed 34.9% in the non-wild-type group. The vancomycin MIC distribution was right shifted, with high-end MICs observed. In the sequenced subset, vancomycin-associated determinants consistent with the vanC pathway (including regulatory and auxiliary components) were detected in five isolates. Beyond vancomycin-related determinants, the WGS subset harbored common resistance genes consistent with the observed multidrug-resistant phenotypes. Conclusions: Vancomycin non-susceptibility was detected among pre-screened poultry-derived Enterococcus isolates in Hungary, and genomic analysis revealed vanC-associated and other peptide antibiotic resistance signatures. These findings support targeted One Health surveillance integrating MIC distributions with genomic resistance determinants in food animal reservoirs. Full article

(This article belongs to the Special Issue Antimicrobial Resistance in Veterinary Pathogens: Phenotypic Surveillance, Genomic Epidemiology, and Control Measures)

17 pages, 955 KB

Open AccessArticle

Determination of Gentamicin: Development and Validation of a Sensitive UPLC-MS/MS Assay According to the European Medicines Agency Guideline

by Raquel Diez, Eva M. Vazquez, Beatriz Romero, Raul de la Puente, Nelida Fernandez, Ana M. Sahagun, M. Jose Diez and Cristina Lopez

Antibiotics 2026, 15(2), 130; https://doi.org/10.3390/antibiotics15020130 - 28 Jan 2026

Abstract

Background/Objectives: Gentamicin (GEN) is an aminoglycoside antibiotic used in veterinary medicine to treat infections caused mainly by Gram-negative bacteria. GEN is a mixture of pharmacologically active components, known as isoforms. The objective was to develop and validate a sensitive, accurate, and precise [...] Read more.

Background/Objectives: Gentamicin (GEN) is an aminoglycoside antibiotic used in veterinary medicine to treat infections caused mainly by Gram-negative bacteria. GEN is a mixture of pharmacologically active components, known as isoforms. The objective was to develop and validate a sensitive, accurate, and precise Ultra-Performance Liquid Chromatography with triple quadrupole mass detector (UPLC-MS/MS) method to quantify the different GEN isoforms in pig plasma and feces using streptomycin as an internal standard. Methods: Solid-phase extraction (SPE) was carried out. A high-strength silica (50 × 2.1 mm, 1.8 µm) column was used for chromatographic separation and a mobile phase of 0.26% HFBA in water (A) and acetonitrile (B) was delivered in a gradient with a flow rate of 0.5 mL/min. The column temperature was 40 °C and the sample injection volume was 30 µL. Results: The method showed good selectivity and specificity, with no interfering peaks. Calibration curves were linear in the range from 0.05 to 0.3 µg/mL for all isoforms in both matrices. Within- and between-run precision and accuracy were satisfactory for the lower limit of quantification (LLOQ), with coefficients of variation (CV) ≤ 13.4% and deviations ≤ 116.5% in plasma and CV ≤ 12.3% with deviations ≤ 101.7% in feces. No carry-over was observed, and analyte stability was confirmed under different storage conditions. Conclusions: The method development fulfilled all validation criteria established by the European Medicine Agency Guideline (EMA/CHMP/ICH/172948/2019). Moreover, the applicability of the method in clinical practice was demonstrated by the quantification of GEN in plasma and feces samples from pigs. Full article

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15 pages, 1274 KB

Open AccessArticle

Pathogen Profiling in Reverse Total Shoulder Arthroplasty: Virulence Traits of Clinical Isolates Before and After Intraoperative Povidone–Iodine Irrigation

by Enrico Bellato, Fabio Longo, Francesca Menotti, Rebecca Mariani, Lucrezia Massobrio, Valentina Bartolotti, Helena Villavicencio, Narcisa Mandras, Alessandro Bondi, Antonio Curtoni, Filippo Castoldi, Giuliana Banche and Valeria Allizond

Antibiotics 2026, 15(2), 129; https://doi.org/10.3390/antibiotics15020129 - 28 Jan 2026

Abstract

Background/Objectives: Reverse total shoulder arthroplasty (RTSA), a commonly performed procedure in elderly patients with osteoarthritis, is frequently complicated by postoperative infections—primarily caused by Cutibacterium acnes and coagulase-negative staphylococci (CoNS)—which remain a major clinical challenge. While standard antiseptic skin protocols can reduce the [...] Read more.

Background/Objectives: Reverse total shoulder arthroplasty (RTSA), a commonly performed procedure in elderly patients with osteoarthritis, is frequently complicated by postoperative infections—primarily caused by Cutibacterium acnes and coagulase-negative staphylococci (CoNS)—which remain a major clinical challenge. While standard antiseptic skin protocols can reduce the bacterial load at the surgical site, they often fail to achieve complete eradication, particularly with C. acnes, a resident species of the shoulder microbiome. Recent evidence indicates that intraoperative povidone–iodine irrigation is effective in significantly decreasing microbial burden; however, a thorough characterization of the virulence factors of the isolated strains remains essential. Methods: A total of 187 clinical strains isolated immediately after RTSA were characterized with respect to their antibiotic resistance profiles and biofilm-forming capacity, and the impact of intraoperative povidone–iodine irrigation on the reduction in bacteria that express these virulence traits was evaluated. Results: Of the 120 C. acnes isolates, 97.67% were susceptible to the tested antimicrobial agents, while only 3.33% exhibited resistance, specifically to clindamycin. In contrast, 53% of CoNS isolates were classified as susceptible, whereas the remaining 47% demonstrated multidrug resistance. Biofilm production was detected in 24% (29/120) of C. acnes and 39% (25/64) of CoNS isolates, with a statistically significant reduction observed after irrigation only for C. acnes. No association was found between biofilm formation and clindamycin resistance in C. acnes, likely due to the low number of resistant isolates. Conversely, among CoNS, a correlation was observed, with the 17.2% of biofilm-producing strains also exhibiting resistance to antimicrobial agents. Conclusions: Notwithstanding the presence of these virulence factors, povidone–iodine irrigation proved effective in substantially reducing the number of bacterial isolates recovered at the surgical site without selecting for strains with enhanced pathogenicity. Notably, the majority of resistant bacteria were detected prior to intraoperative irrigation. This intraoperative procedure may be a key approach to reducing prosthetic joint infections frequently caused by more virulent pathogens, which are unlikely to be selected following this disinfection strategy. Full article

(This article belongs to the Special Issue Antibiotic Treatment on Surgical Infections)

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13 pages, 322 KB

Open AccessArticle

The Invisible Excess: Too Long Antibiotic Duration in the Pediatric Emergency Care

by Miguel Ángel Molina-Gutiérrez, María Camacho-Gil, Virginia Santana-Rojo and Luis Escosa-García

Antibiotics 2026, 15(2), 128; https://doi.org/10.3390/antibiotics15020128 - 27 Jan 2026

Abstract

Background/Objectives: Antibiotics are among the most commonly prescribed medicines in the Pediatric Emergency Department (PED). The overuse of antibiotics is directly linked to the emergence of resistance. Recent clinical trials have emerged in children in which short courses have proven to be [...] Read more.

Background/Objectives: Antibiotics are among the most commonly prescribed medicines in the Pediatric Emergency Department (PED). The overuse of antibiotics is directly linked to the emergence of resistance. Recent clinical trials have emerged in children in which short courses have proven to be as effective as longer courses. The aim of this study was to analyze the duration of antibiotic treatment prescribed in our PED for the most important and common infections in children and to compare with the best available evidence. Methods: A single-center retrospective study was conducted in the PED of a tertiary hospital. We evaluated outpatients from birth to 16 years who were discharged with antibiotic therapy during a 1-year period (2022) to classify duration of therapy as appropriate or inappropriate. Results: 1972 antibiotic prescriptions were analyzed. 28.3% (560/1972) of the prescriptions were classified as inappropriate according to duration of therapy; 551 (98.3%) were due to longer-than-recommended duration. The condition associated with the highest number of inappropriate prescriptions was Uncomplicated Community-acquired Pneumonia (CAP) (427/560; 76.2%). When focusing on each infectious syndrome, Uncomplicated CAP had also the highest percentage of inappropriate duration (92.6%) comparing with appropriate prescription. Regarding specific types of antibiotics, amoxicillin accounted for the highest number of inappropriate prescriptions (422/560; 75.4%). Conclusions: A longer-than-recommended prescription of antibiotics is frequent in the Pediatric Emergency Department. Uncomplicated CAP is the condition associated with the highest number of inappropriate duration of antibiotics in our setting. Full article

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

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36 pages, 4837 KB

Open AccessArticle

Design, Synthesis, Spectral, Structural Analysis, and Biological Evaluation of Novel Pyrazole Derivatives as Anti-Tumor, Antimicrobial, and Anti-Biofilm Agents

by Christina Zalaru, Florea Dumitrascu, Constantin Draghici, Marilena Ferbinteanu, Isabela Tarcomnicu, Maria Marinescu, Zenovia Moldovan, George Mihai Nitulescu, Rodica Tatia and Marcela Popa

Antibiotics 2026, 15(2), 127; https://doi.org/10.3390/antibiotics15020127 - 27 Jan 2026

Abstract

Objective: Based on our previous findings, we designed new molecules by extending functionalized pyrazole derivatives containing iodine atoms, which are linked via an amino bond to halogen-substituted phenyl groups. In addition, these newly developed pyrazole compounds exhibit anti-tumor, antibacterial, and anti-biofilm activities. Methods: [...] Read more.

Objective: Based on our previous findings, we designed new molecules by extending functionalized pyrazole derivatives containing iodine atoms, which are linked via an amino bond to halogen-substituted phenyl groups. In addition, these newly developed pyrazole compounds exhibit anti-tumor, antibacterial, and anti-biofilm activities. Methods: Three new series of pyrazole compounds were designed. Fifteen novel pyrazole derivatives, distributed across three series (4a–d, 5a–d, and 6a–g), were synthesized and structurally characterized by ¹H-NMR, ¹³C-NMR, FTIR, UV-Vis spectroscopy, and elemental analysis. Results: Among them, compound 4c, which exhibited notable anti-tumor activity, crystallized in a monoclinic system and was further analyzed via single-crystal X-ray diffraction. All synthesized compounds were evaluated in vitro on NCTC normal fibroblast cells and HEp-2 tumor epithelial cells. Compound 4c demonstrated significant anti-tumor activity while displaying no cytotoxic effects on normal cells. The antibacterial and anti-biofilm activities of the compounds were also assessed against four bacterial strains. Compounds 5a and 5c exhibited the highest antibacterial activity against Staphylococcus aureus ATCC 25923, both with a minimum inhibitory concentration (MIC) of 0.023 μg/mL. Additionally, compounds 4a, 5a, 6a, 6e, and 6f showed the strongest anti-biofilm effects, each presenting a minimum biofilm inhibition concentration (MBIC) of 0.023 μg/mL. ADME and ADMET in silico predictions indicated that all compounds exhibit generally favorable, drug-like physicochemical properties. Conclusions: The study reinforces the applicability of these compounds as promising anticancer, antibacterial, and anti-biofilm drugs. Full article

(This article belongs to the Special Issue Design and Synthesis of Novel Antibiotics, 2nd Edition)

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21 pages, 7534 KB

Open AccessArticle

Mechanistic Insights into the Antimicrobial Effect of Benzodioxane-Benzamides Against Escherichia coli

by Lorenzo Suigo, Alessia Lanzini, Valentina Straniero and William Margolin

Antibiotics 2026, 15(2), 126; https://doi.org/10.3390/antibiotics15020126 - 27 Jan 2026

Abstract

Background/Objectives: The bacterial cell division machinery is emerging as an attractive target for antimicrobial compounds. FtsZ, a highly conserved essential division protein, is the target for a number of small molecules such as benzamides. Recent studies show that benzodioxane-benzamides (BDOBs) are among [...] Read more.

Background/Objectives: The bacterial cell division machinery is emerging as an attractive target for antimicrobial compounds. FtsZ, a highly conserved essential division protein, is the target for a number of small molecules such as benzamides. Recent studies show that benzodioxane-benzamides (BDOBs) are among the most potent inhibitors of FtsZ function in Gram-positive bacteria, although their ability to inhibit Gram-negative FtsZ, in particular Escherichia coli FtsZ, has been more controversial. Methods: Here, we use genetic and cytological methods to demonstrate that FtsZ of efflux pump-disabled E. coli can be efficiently targeted by BDOBs. Results: We show that engineered mutants and spontaneous variants map in or near the interdomain cleft (IDC) of FtsZ that confers resistance to BDOBs, similar to previous results with Gram-positive FtsZs. We also uncover spontaneous extragenic mutants that can confer high levels of resistance to at least one potent BDOB, including a mutant that encodes a novel hyperfission variant of the essential cell division protein FtsW. Conclusions: Our evidence indicates that as with Gram-positive bacteria, the IDC of Gram-negative bacterial FtsZ is directly targeted by BDOBs, provided efflux pumps are disabled. We also conclude that FtsZ-independent factors can influence the effect of BDOBs on E. coli cell division, including activation of division septum synthesis. Full article

(This article belongs to the Section Genetic and Biochemical Studies of Antibiotic Activity and Resistance)

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22 pages, 2039 KB

Open AccessReview

Phage-Based Approaches to Chronic Pseudomonas aeruginosa Lung Infection in Cystic Fibrosis

by Wontae Hwang, Ji Hyun Yong, Bryan R. Lenneman and Lael M. Yonker

Antibiotics 2026, 15(2), 125; https://doi.org/10.3390/antibiotics15020125 - 27 Jan 2026

Abstract

Chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) represent one of the most treatment-refractory bacterial diseases, sustained by biofilm formation, metabolic dormancy, and adaptive antibiotic resistance evolution. While bacteriophage (phage) therapy has emerged as a promising alternative for multidrug-resistant (MDR) pathogens, clinical [...] Read more.

Chronic Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) represent one of the most treatment-refractory bacterial diseases, sustained by biofilm formation, metabolic dormancy, and adaptive antibiotic resistance evolution. While bacteriophage (phage) therapy has emerged as a promising alternative for multidrug-resistant (MDR) pathogens, clinical studies in CF have demonstrated transient reductions in bacterial burden without achieving complete eradication. This review integrates molecular, evolutionary, and immunological findings to explain the multifactorial barriers that limit phage therapeutic efficacy in chronic CF infections. We highlight three major obstacles: (i) bacterial dormancy and persistence within biofilms that restrict phage adsorption and replication; (ii) hypermutability and extensive genotypic diversification of CF-adapted P. aeruginosa, which accelerate phage resistance evolution and necessitate broad host-range coverage; and (iii) CF-specific immune constraints—including a dysfunctional innate immune system and phage-neutralizing humoral immunity—that reduce phage bioavailability and undermine sustained bacterial clearance. Emerging strategies to overcome these challenges include the discovery of dormant-targeting phages capable of replicating in metabolically quiescent cells, evolution-informed phage training to delay resistance evolution, and synthetic phage engineering approaches designed to disrupt biofilms and expand host-range coverage. In parallel, computational or artificial intelligence (AI)-guided frameworks for phage cocktail design and cystic fibrosis transmembrane conductance regulator (CFTR) modulator-mediated restoration of host immune function together offer a more integrated therapeutic paradigm that unites phage biology and host immune context. By unifying clinical outcomes with mechanistic, evolutionary, and immunological perspectives, this review outlines a next-generation framework for phage therapy in CF aimed at achieving more durable therapeutic outcomes. Full article

(This article belongs to the Special Issue New Insights Toward the Development of Novel Inhibitors of S. aureus and P. aeruginosa Factors)

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31 pages, 1311 KB

Open AccessArticle

Mapping Escherichia coli in Women with Simple Urinary Tract Infections: Phenotypic ESBL/AmpC Screening and Whole-Genome Insights from Oman

by Aisha Al-Mufarji, Meher Rizvi, Nawal Al-Kindi, Nada Al-Tamtami and Zaaima Al-Jabri

Antibiotics 2026, 15(2), 124; https://doi.org/10.3390/antibiotics15020124 - 27 Jan 2026

Abstract

Background/Objectives: Simple urinary tract infections (sUTIs) are common in women and increasingly affected by multidrug-resistant (MDR) Escherichia coli. Extended-spectrum β-lactamase (ESBL) and AmpC producers restrict oral treatment options and promote carbapenem use. This study aimed to (i) describe the etiology and antimicrobial [...] Read more.

Background/Objectives: Simple urinary tract infections (sUTIs) are common in women and increasingly affected by multidrug-resistant (MDR) Escherichia coli. Extended-spectrum β-lactamase (ESBL) and AmpC producers restrict oral treatment options and promote carbapenem use. This study aimed to (i) describe the etiology and antimicrobial susceptibility of sUTIs in women of reproductive age in Oman, (ii) determine the prevalence of ESBL/AmpC-producing E. coli, (iii) evaluate nitroxoline, fosfomycin, mecillinam, and temocillin against ESBL and non-ESBL E. coli, and (iv) characterize circulating clones and resistance/virulence determinants using whole-genome sequencing (WGS). Methods: In this multicentric study (September 2022–August 2023), 795 uropathogens from 762 women (15–50 years) with sUTI were collected from four Omani hospitals. Identification and susceptibility testing of E. coli (n = 489) and Klebsiella pneumoniae (n = 140) using BD Phoenix and MALDI-TOF MS was performed (CLSI 2022). Thirty ESBL-producing and 82 non-ESBL E. coli underwent phenotypic ESBL/AmpC testing and evaluation of mecillinam, temocillin, nitroxoline, and fosfomycin. WGS was performed on 26 isolates (23 ESBL, 3 wild type) and analyzed for MLST, and SNP phylogeny using ResFinder, CARD, PlasmidFinder, VirulenceFinder. Statistical significance was set at p < 0.05. Results: E. coli (62%) and K. pneumoniae (18%) were the predominant pathogens. E. coli showed high susceptibility to nitrofurantoin (~97%), carbapenems, aminoglycosides, and piperacillin–tazobactam, but reduced susceptibility to cephalosporins, fluoroquinolones, cotrimoxazole, and ampicillin. ESBL prevalence ranged from 38–51%; AmpC producers were rare (4.6%). Mecillinam, nitroxoline, and fosfomycin exhibited 100% activity against both ESBL and non-ESBL isolates; temocillin showed 89.3% activity in ESBL strains. WGS identified 15 sequence types dominated by ST-131, ST-1193, ST-73, and ST-174, with blaCTX-M-15 as the major ESBL genotype. Conclusions: sUTIs in Oman show a high burden of ESBL-producing E. coli. Nitrofurantoin, mecillinam, fosfomycin, temocillin, and nitroxoline would be effective carbapenem-sparing oral options. Continuous phenotypic and genomic surveillance are crucial to guide antimicrobial therapy and stewardship. Full article

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15 pages, 272 KB

Open AccessArticle

Early Life Antibiotic Exposure and Intestinal Colonization by Enterobacteriaceae upon Admission to a Neonatal Referral Unit: A Case–Control Study

by Sergio Agudelo-Pérez, Gloria Troncoso, Martha Alvarez-Olmos, Maria Pineda, Adriana Moscote and María Paula Molina Pérez

Antibiotics 2026, 15(2), 123; https://doi.org/10.3390/antibiotics15020123 - 27 Jan 2026

Abstract

Background/Objectives: Intestinal colonization by Enterobacteriaceae, including extended-spectrum β-lactamase-producing (ESBL-E) and carbapenemase-producing (E-CPE) strains, is an early marker of multidrug-resistant infections in neonates, particularly those transferred from lower-complexity hospitals. This study aimed to identify factors associated with intestinal Enterobacteriaceae colonization upon admission to a [...] Read more.

Background/Objectives: Intestinal colonization by Enterobacteriaceae, including extended-spectrum β-lactamase-producing (ESBL-E) and carbapenemase-producing (E-CPE) strains, is an early marker of multidrug-resistant infections in neonates, particularly those transferred from lower-complexity hospitals. This study aimed to identify factors associated with intestinal Enterobacteriaceae colonization upon admission to a level IV neonatal referral unit in Colombia, with a focus on prior antibiotic exposure. Methods: We conducted a retrospective case–control study, including all neonates transferred from peripheral hospitals and screened with rectal swabs at admission. Cases were neonates colonized with Enterobacteriaceae, and controls were non-colonized neonates admitted during the same period. Multivariable logistic regression models were used to evaluate three exposure dimensions: prior antibiotic use (yes/no), number of agents, and the WHO AWaRe classification. A secondary analysis was performed to assess the factors associated with ESBL-E and E-CPE colonization. Results: Among the 435 referred neonates, 87 (20.0%) were colonized, predominantly Klebsiella pneumoniae (53.6%) and Escherichia coli (19.5%). Prior antibiotic use (aOR 3.01; 95% CI 1.47–6.37), exposure to two agents (aOR 4.13; 95% CI 1.94–8.89) and use of AWaRe Access antibiotics (aOR 22.2; 95% CI 5.83–101) were strongly associated with colonization. Longer hospitalization and central catheter use were also associated with greater colonization odds, whereas total parenteral nutrition showed a protective association. In the sub-analysis, Access, Watch, and Reserve antibiotics were independently associated with ESBL-E and E-CPE colonization. Conclusions: Among transferred neonates, prior antibiotic exposure, particularly AWaRe-classified agents, showed the strongest association with intestinal colonization by Enterobacteriaceae, including ESBL-E/CPE phenotypes. Strengthening antimicrobial stewardship in referral facilities and implementing risk-based screening at admission may help reduce colonization and limit the spread of resistance. Full article

(This article belongs to the Special Issue Antimicrobial Stewardship in Neonatal Intensive Care)

12 pages, 1350 KB

Open AccessArticle

Additional Erythrocyte Field Is Helpful for Graphic Type Differentiation of Cell Count Determination Between Acute Periprosthetic Joint Infection and Hematoma

by Florian Hubert Sax, Marius Hoyka, Benedikt Paul Blersch, Elke Weissbarth, Philipp Schuster, Irina Berger, Hansjörg Baum and Bernd Fink

Antibiotics 2026, 15(2), 122; https://doi.org/10.3390/antibiotics15020122 - 26 Jan 2026

Abstract

Background/Objectives: This study was designed to verify the hypothesis that graphical cell differentiation of synovial cell count analysis is helpful for diagnosis of acute periprosthetic joint infection (PJI) and that the additional erythrocyte field has advantages to differentiate PJI from hematoma. Methods [...] Read more.

Background/Objectives: This study was designed to verify the hypothesis that graphical cell differentiation of synovial cell count analysis is helpful for diagnosis of acute periprosthetic joint infection (PJI) and that the additional erythrocyte field has advantages to differentiate PJI from hematoma. Methods: A total of 77 total knee arthroplasties and 31 total hip arthroplasties underwent aspiration within six weeks of primary implantation. The aspirate was analyzed with the cell counter Yumizen H500 and examined by cultivation. Serum CRP was also determined. A total of 43 patients underwent revision and microbiological and histological analysis of the periprosthetic tissue, according to Morowitz and Krenn, was performed. The ICM criteria for diagnosing PJI were used. Results: Thirty-two cases (29.6%) were classified as acute infection. The graphical type differentiation LMNE (leukocyte–monocyte–neutrophil–eosinophil) showed 28 cases with type II (infection type), 63 cases with type IV (indifferent type), 13 cases with type V (hematoma type with a peak in the erythrocyte field) and 4 cases with type VI (mixed infection and hematoma). The LMNE matrix assessment had an accuracy of 98.7%, sensitivity of 96.9%, specificity of 98.7%, positive predictive value of 96.9%, negative predictive value of 98.7%, a positive likelihood ratio of 73.62, and a negative likelihood ratio of 0.03. Only one single non-infectious hematoma sample was misclassified as type VI (mixed infection/hematoma). Conclusions: The graphical type differentiation of the cell count analysis of synovial aspirates is a helpful method for diagnosis of acute periprosthetic joint infection and differentiating between hematoma and real early periprosthetic infections. This report shows that the new erythrocyte field of the Yumizen H500 is a useful additional diagnostic tool. Full article

(This article belongs to the Special Issue Diagnostics, Antibiotic Usage and Surgery Related Techniques in Prevention and Treatment of Prosthetic Joint and Implant Related Infections)

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13 pages, 271 KB

Open AccessArticle

Exploring the Potential of Donkey Milk in Enhancing Pneumonia Treatment Outcomes—Pilot Study

by Violeta Kolarov, Anika Trudić, Maja Bogdan, Jovan Javorac, Ivana Čabarkapa, Dragana Tomanić and Ljubiša Šarić

Antibiotics 2026, 15(2), 121; https://doi.org/10.3390/antibiotics15020121 - 26 Jan 2026

Abstract

Background/Objectives: Community-acquired pneumonia (CAP) is a major cause of hospitalization and mortality worldwide, with growing interest in adjunctive therapies to enhance treatment outcomes. Donkey milk, long used in traditional medicine for respiratory illnesses, contains bioactive compounds with antimicrobial, anti-inflammatory, and immunomodulatory properties that [...] Read more.

Background/Objectives: Community-acquired pneumonia (CAP) is a major cause of hospitalization and mortality worldwide, with growing interest in adjunctive therapies to enhance treatment outcomes. Donkey milk, long used in traditional medicine for respiratory illnesses, contains bioactive compounds with antimicrobial, anti-inflammatory, and immunomodulatory properties that may benefit patients with CAP. Methods: Sixty hospitalized patients were prospectively allocated into two groups based on their consent to receive adjunctive donkey milk supplementation: one received standard antibiotic therapy plus 250 mL of pasteurized donkey milk twice daily for one month, while the control group received antibiotics alone. Results: Patients consuming donkey milk showed significantly faster reductions in C-reactive protein CRP and procalcitonin PCT levels, greater radiological improvement (p < 0.001), and a shorter average hospital stay (12.46 vs. 14.16 days). Logistic regression analysis identified donkey milk consumption as a significant predictor of shorter hospital stay. Importantly, no adverse effects were reported, and compliance with the supplementation was high. Conclusions: These findings suggest that pasteurized donkey milk may serve as a safe and effective natural adjunct to standard antibiotic therapy in managing CAP, with potential to enhance recovery and reduce hospital stay. Further large-scale studies are needed to validate these results and explore broader applications of donkey milk in infectious diseases. Full article

13 pages, 671 KB

Open AccessArticle

Six-Year Environmental Surface Hygiene Monitoring in Hungarian School Kitchens (2019–2024): Hotspots, Seasonality, and One Health Implications

by András Bittsánszky, Lili A. Lukács, Márton Battay, Miklós Süth and András J. Tóth

Antibiotics 2026, 15(2), 120; https://doi.org/10.3390/antibiotics15020120 - 26 Jan 2026

Abstract

Background/Objectives: Institutional catering serves vulnerable populations, including schoolchildren. Surfaces in food preparation environments are key control points for food safety and reservoirs and transmission routes for antimicrobial-resistant (AMR) bacteria. This study characterized the hygienic status of food-contact surfaces (FCS) and non-food-contact surfaces [...] Read more.

Background/Objectives: Institutional catering serves vulnerable populations, including schoolchildren. Surfaces in food preparation environments are key control points for food safety and reservoirs and transmission routes for antimicrobial-resistant (AMR) bacteria. This study characterized the hygienic status of food-contact surfaces (FCS) and non-food-contact surfaces (NFCS) in Hungarian school kitchens, identified contamination hotspots, and examined how routine monitoring can support AMR prevention. Methods: We retrospectively analyzed routine environmental hygiene monitoring records from 96 school kitchens (2019–2024). In total, 8412 swab samples were collected, 8407 had quantifiable counts, 6233 from FCS (e.g., plates, trays, boards, utensils), and 2174 from NFCS (e.g., sinks, fridges, workers’ hands). Total aerobic mesophilic counts were measured with a redox-potential method and expressed as CFU/100 cm²; 250 CFU/100 cm² (2.4 log₁₀) was the hygienic threshold. Results: Overall, 12.4% of surfaces exceeded the threshold. Non-food-contact surfaces were more likely to be non-compliant than food-contact surfaces (OR 2.77, 95% CI 2.43–3.17; p < 0.001). Hotspots included transport-container lids (67.2% non-compliant; OR 43.82), sink basins (32.8%; OR 10.46), and cutting boards (21.6%; OR 5.89). Seasonally, non-compliance was highest in summer (16.5%) and lowest in winter (9.0%; p < 0.001). Conclusions: Multi-year monitoring revealed substantial contamination concentrated in a few hotspots that, within a One Health framework—which recognizes the interconnectedness of human, animal, and environmental health—may represent environmental reservoirs and cross-contamination nodes relevant to AMR prevention. Targeted optimization of cleaning and disinfection for these surfaces, combined with trend analysis of indicator data and periodic AMR-focused environmental sampling, could reduce foodborne and AMR-related risks in public catering. Full article

(This article belongs to the Special Issue Antimicrobial Resistance and One Health: Environmental Health, Food Safety, and Practice of Health Professionals)

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15 pages, 451 KB

Open AccessArticle

Impact of Vancomycin Resistance on 30-Day Mortality in Solid Organ Transplant Recipients with Enterococcus faecium Bloodstream Infections: A Retrospective Cohort Analysis

by Maria Mazzitelli, Alberto Enrico Maraolo, Umberto Barbieri, Vincenzo Scaglione, Lolita Sasset, Lucrezia Furian, Umberto Cillo, Gino Gerosa, Monica Loy, Emanuele Cozzi, Patrizia Burra, Federico Rea and Annamaria Cattelan

Antibiotics 2026, 15(2), 119; https://doi.org/10.3390/antibiotics15020119 - 26 Jan 2026

Abstract

Background: Enterococcus faecium bloodstream infections (EF-BSI) cause significant morbidity and mortality in solid organ transplant (SOT) recipients, with the role of vancomycin resistance (VR) remaining controversial as an independent driver. Methods: This was a retrospective cohort study including SOT recipients with EF-BSI [...] Read more.

Background: Enterococcus faecium bloodstream infections (EF-BSI) cause significant morbidity and mortality in solid organ transplant (SOT) recipients, with the role of vancomycin resistance (VR) remaining controversial as an independent driver. Methods: This was a retrospective cohort study including SOT recipients with EF-BSI at our institution from 2019 to 2023. We used Cox proportional hazards regression to identify predictors of 30-day all-cause mortality. A time-dependent covariate was used to model the effects of receiving targeted, effective antibiotic therapy. Results: A total of 79 patients were included (26.6%, with VR). The overall 30-day mortality was 12.7% (10/79). In univariable analysis, septic shock (Hazard Ratio, HR: 17.1, 95% CI: 3.64–80.8, p < 0.001), the need for Continuous Venovenous Hemofiltration (HR: 6.40, 95% CI: 1.85–22.1, p = 0.003), and a Pitt Bacteremia Score ≥ 2 (HR: 5.17, 95%CI: 1.10–24.3, p = 0.038) were associated with increased mortality, while source control was protective (HR: 0.20, 95% CI: 0.05–0.76, p = 0.018). In the final multivariable model, only septic shock remained an independent predictor of 30-day mortality (HR: 11.4, 95% CI: 1.63–79.5, p = 0.014). VR was not significantly associated with mortality, though the confidence interval was wide and included clinically meaningful effects (HR: 2.07, 95% CI: 0.40–10.6, p = 0.4). Conclusions: In SOT recipients with EF-BSI, 30-day mortality is overwhelmingly driven by the host’s physiological response, manifested as septic shock, rather than the VR profile of the pathogen. The early recognition of severe sepsis/septic shock and the aggressive implementation of supportive care and source control measures in this setting are crucial. Full article

(This article belongs to the Special Issue Antimicrobial Resistance in the Community Setting: The Other Side of the Coin)

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14 pages, 1313 KB

Open AccessArticle

From Screening to Outcomes: Fourteen-Year Hospital-Wide Surveillance of Alert Pathogens and Antimicrobial Use in a Paediatric Tertiary Hospital

by Aleksandra Tukendorf, Julia Burzyńska, Katarzyna Semczuk, Ryszard Sot and Katarzyna Dzierżanowska-Fangrat

Antibiotics 2026, 15(2), 118; https://doi.org/10.3390/antibiotics15020118 - 26 Jan 2026

Abstract

Background/Objectives: Infection prevention and control (IPC) programs combine pathogen-targeted measures (e.g., admission screening) with hospital-wide standard precautions (e.g., hand hygiene, HH). We assessed temporal associations between screening, HH, antimicrobial stewardship (AMS), and hospital-level outcomes in a tertiary paediatric hospital. Methods: This [...] Read more.

Background/Objectives: Infection prevention and control (IPC) programs combine pathogen-targeted measures (e.g., admission screening) with hospital-wide standard precautions (e.g., hand hygiene, HH). We assessed temporal associations between screening, HH, antimicrobial stewardship (AMS), and hospital-level outcomes in a tertiary paediatric hospital. Methods: This study was a retrospective hospital-wide ecological time-series at the Children’s Memorial Health Institute. Annual aggregate data: 2011–2024 for screening, colonisation, and healthcare-associated infections (HAIs) with alert pathogens; 2016–2024 for antibiotic consumption (ATC J01, systemic antibacterials). Process indicators: number of screening tests and alcohol-based hand rub (ABHR) consumption per 1000 patient-days (PD). Outcomes: colonisations/HAIs per 1000 PD and defined daily doses (DDD) per 1000 PD overall and by class. Trends used linear regression and Spearman’s rank correlation. Results: Screening intensity increased from 39 to 150/1000 PD (slope +8.3/year; R² = 0.90; p < 0.001). Detected colonisation rose (2.5 → peak 8.05/1000 PD in 2023; slope +0.39; R² = 0.81; p < 0.001), while multidrug-resistant-organism (MDRO)-attributable HAIs remained low/stable (0.27–0.62/1000 PD; slope −0.014; p = 0.023). ABHR consumption increased from 26.1 to 78.0 L/1000 PD in 2020 (p < 0.001) and partially normalised to 60.0 in 2024 (>2 × baseline). Overall ATC J01 showed no long-term linear trend (~278–356 DDD/1000 PD; +2.57/year; p = 0.46), but class mix shifted: carbapenems, fluoroquinolones, and amoxicillin–clavulanate decreased; third/fourth-generation cephalosporins, piperacillin/tazobactam, and glycopeptides increased. Conclusions: In this tertiary paediatric setting, expansion of risk-based admission screening and sustained implementation of horizontal IPC measures were accompanied by increased detection of colonisation with alert pathogens, while MDRO-attributable HAIs remained low and stable at the hospital level. Over the same period, AMS activity coincided with a redistribution in antibiotic class use without a clear long-term reduction in total antibiotic consumption. These hospital-level findings are descriptive and hypothesis-generating; causal inference is limited by the ecological study design, and the heterogeneous, multispecialty structure of a tertiary paediatric centre. Full article

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

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