Search Results (2,907)

Micro-organisms are abundant in nature and can also be found in hospital settings, causing high rates of infections. This study aimed to identify bacteria isolated from a veterinary hospital, as well as to perform antimicrobial susceptibility testing using the disk diffusion method (Kirby–Bauer), biofilm production tests using 96-well polystyrene microtiter plates and crystal violet dye, and genetic analysis of the ica operon of Staphylococcus isolates. Three collections were made from eleven surfaces and objects in the hospital’s non-critical areas (general areas) and critical areas (surgical center), totaling thirty-three samples. A total of 66 different bacterial isolates were obtained, with 77% (51/66) Gram-positive and 23% (29/66) Gram-negative. Resistance profiles were found for multidrug-resistance (MDR), methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), and other unidentified species of methicillin-resistant coagulase-negative (MRCNS) and extended-spectrum beta-lactamase (ESBL), as well as biofilm production rates of 57% (38/66) of the isolates. Analysis of the operon genes for Staphylococcus sp. showed divergence in some samples when compared to the phenotypic test performed. In summary, there is a high presence of micro-organisms with resistance and virulence factors spread throughout the various areas of the veterinary hospital. Full article

Linezolid (LNZ) is a synthetic oxazolidinone antibiotic that inhibits bacterial protein synthesis through binding to ribosomal RNA, also preventing the assembly of the initiation complex during translation. It is one of the last-line therapeutic options for serious infections caused by problematic Gram-positive pathogens, including vancomycin-resistant and multidrug-resistant Enterococcus species. Data from recent large-scale studies show a 2.5-fold increase in the prevalence of clinical LNZ-resistant enterococci (LRE) over the past decade with a global detection rate of 1.1% for LNZ-resistant E. faecium (LREfm) and 2.2% for LNZ-resistant E. faecalis (LREfs). Most reported cases have originated from China, followed by South Korea and the United States. LREfm typically belongs to the high-risk clonal complex 17, whereas LREfs demonstrates a heterogeneous population structure. Mutations in the 23S rRNA and ribosomal proteins, as well as acquired resistance genes such as cfr, optrA, and poxtA are involved in the development of LNZ resistance among enterococci. Whole-genome sequencing (WGS) has been recognized as a gold standard for identifying the underlying molecular mechanisms. It exposes that numerous LRE isolates possess multiple LNZ resistance determinants and mutations, further complicating the treatment strategies. The present review article summarizes all known mutational and non-mutational LNZ resistance mechanisms and presents a global overview of WGS-based studies with emphasis on resistome analysis of clinical LREfs and LREfm isolates published in the literature during the period 2014–2025. Full article

Current diagnostic methods for bacterial infections in critically ill patients, including ventilator-associated pneumonia (VAP), are time-consuming, while empirical antibiotic therapy contributes to rising resistance. Bacteria-derived volatile organic compounds (VOCs) are being explored as specific biomarkers for pathogen identification and treatment monitoring. This study expands knowledge of Escherichia coli metabolism by identifying VOCs produced by both multidrug-resistant and susceptible strains, characterizing their temporal profiles during growth, and assessing VOC profile changes after imipenem exposure. Reference strains and 21 clinical isolates (derived from BAL samples of VAP patients) were cultured under controlled conditions. Headspace VOCs were preconcentrated using multibed sorption tubes and analyzed by gas chromatography–mass spectrometry (GC-MS), with compound identities confirmed using external standards. Sampling at seven time points over 24 h cultures revealed three VOC emission patterns: continuous release, temporary maximum, and compound uptake. In total, 57 VOCs were identified from the susceptible strain and 41 from the resistant one, with dimethyl disulfide, 2-butenal, ethyl acetate, and furan elevated in the resistant strain. Imipenem addition altered VOC production in the susceptible strain, with levels of six compounds elevated and seven reduced, while resistant profiles remained stable. Clinical isolates produced 71 VOCs, showing greater metabolic diversity and highlighting the relevance of isolate-derived VOCs in future studies. Full article

Antibiotics have dramatically reduced the burden of infectious diseases since their discovery, but the accelerating rise in antimicrobial resistance (AMR) now threatens these gains. AMR was responsible for nearly 5 million deaths in 2023 and continues to undermine the efficacy of existing treatments, particularly in low- and middle-income countries. While efforts to address AMR have focused heavily on antibiotic stewardship and new drug development, vaccines represent a powerful yet underutilized tool for prevention. By reducing the incidence of bacterial infections, vaccines lower antibiotic consumption, interrupt transmission of resistant strains, and minimize the selective pressures that drive resistance. Unlike antibiotics, vaccines offer long-lasting protection, rarely induce resistance, and confer indirect protection through herd immunity. This review examines the global burden and drivers of AMR, highlights the unique advantages of vaccines over antibiotics in mitigating AMR, and surveys the current development pipeline of vaccines targeting key multidrug-resistant bacterial pathogens. Full article

Objectives: To evaluate the in vitro antimicrobial activity of TiAB, a compound based on silver-bound titanium dioxide, against clinical isolates from dermatological infections. Methods: We tested 155 strains clinically isolated from ulcers and skin infections, including MRSA, ESBL-producing Enterobacterales, and P. aeruginosa. MIC and MBC values were determined using broth microdilution according to CLSI guidelines. Time-kill assays were performed at 0.5×, 1×, and 2× MIC. Median values were used to describe susceptibility profiles. Results: TiAB exhibited strong bactericidal activity against Gram-negative bacteria, including ESBL-positive E. coli and K. pneumoniae, with complete killing at 2× MIC (4–8%) within 4–8 h. Gram-positive pathogens exhibited higher MICs (≥8%) and limited response within 24 h; however, extending exposure to 48 h resulted in enhanced activity. Conclusions: TiAB exhibited in vitro bactericidal activity with median MIC values ranging from 1% to 2% (w/v) against Gram-negative clinical isolates such as E. coli and P. aeruginosa, and 2% to 4% against Gram-positive strains including MRSA. Time-kill assays confirmed ≥3 log₁₀ CFU/mL reductions for Gram-negative bacteria at 2× MIC within 24 h. These results suggest TiAB’s potential as a topical antimicrobial agent, though further in vivo studies are needed to validate its safety and efficacy. Full article

Background: The emergence and spread of the tigecycline resistance gene tet(A)-v1 in carbapenem-resistant Klebsiella pneumoniae (CRKP) poses significant public health challenges. However, the prevalence of tet(A)-v1-positive CRKP, especially in pediatric patients, remains poorly understood. This study aims to address the gap by performing an in-depth analysis of isolates collected from a children’s hospital in China. Methods: A 4-year retrospective study was conducted in the children’s hospital in Suzhou, China. Non-duplicated specimens were obtained from pediatric patients, and antimicrobial susceptibility profiles were assessed. Whole-genome sequencing and bioinformatics analyses were conducted to characterize the genetic background, antimicrobial resistance determinants, hypervirulence-associated genes, diversity of tet(A)-v1-carrying plasmids, the genetic environment of tet(A)-v1, and the potential for clonal transmission. Conjugative transferability of tet(A)-v1-carrying plasmids was also evaluated via conjugation assays. Results: Of the 73 tet(A)-v1-positive CRKP isolates from pediatric patients, 10.96% were non-susceptible to tigecycline. These isolates exhibited high genetic diversity, spanning across 13 STs (sequence types), with ST17 being predominant. Three carbapenemases were identified, with IMP being the most common. Isolates from diverse backgrounds, such as ST17, ST20, ST323, ST792, and ST3157, demonstrated evidence of clonal transmission. The tet(A)-v1 gene was located on 14 distinct plasmids across seven replicon types, with IncFIA/IncHI1 and IncFII being most commonly detected. All tet(A)-v1-carrying plasmids were multidrug-resistant, and 68.49% were conjugatively transferable, indicating a high potential for horizontal transfer. Four genetic contexts bordering tet(A)-v1 were identified, which points to active clonal dissemination. Conclusions: Although limited to a single hospital, this study represents one of the first in-depth investigations of tet(A)-v1-positive CRKP in pediatric patients, providing valuable insights into the prevalence and spread of tet(A)-v1 in this vulnerable group. These findings emphasize the urgent need for enhanced surveillance and infection control measures to curb the spread of tet(A)-v1-positive CRKP in pediatric healthcare environments, offering critical insights to mitigate its public health impact. Full article

Background/Objectives: The global increase in multidrug-resistant (MDR) bacterial infections underscores the urgent need for effective and sustainable antimicrobial alternatives. This study investigates the antimicrobial activity of exometabolite-based formulations (ExAFs), derived from the cell-free supernatants (CFS) of native lactic acid bacteria (LAB) applied individually or in combination thereof, against MDR-Escherichia coli strain L1PEag1. Methods: Fourteen ExAFs were screened for inhibitory activity using time–kill assays, and structural damage to bacterial cells was assessed via scanning and transmission electron microscopy (SEM/TEM). The most potent formulation was further characterized by liquid chromatography–tandem mass spectrometry (LC–MS/MS) employing a Sequential Windowed Acquisition of All Theoretical Fragment Ion Mass Spectra (SWATH) approach for untargeted metabolite profiling. Results: Among the tested formulations, E10, comprising CFS from Weissella cibaria UTNGt21O, exhibited the strongest inhibitory activity (zone of inhibition: 17.12 ± 0.22 mm), followed by E1 (CFS from Lactiplantibacillus plantarum Gt28L and Lactiplantibacillus plantarum Gt2, 3:1 v/v) and E2 (Gt28L CFS + EPS from Gt2, 3:1 v/v). Time–kill assays demonstrated rapid, dose-dependent bactericidal activity: E1 and E10 achieved >98% reduction in viable counts within 2–3 h, at 1× MIC, while E2 sustained 98.24% inhibition over 18 h, at 0.25× MIC. SEM and TEM revealed pronounced ultrastructural damage, including membrane disruption, cytoplasmic condensation, and intracellular disintegration, consistent with a membrane-targeting mode of action. Metabolomic profiling of E10 identified 22 bioactive metabolites, including lincomycin, the proline-rich peptide Val–Leu–Pro–Val–Pro–Gln, multiple flavonoids, and loperamide. Several compounds shared structural similarity with ribosomally synthesized and post-translationally modified peptides (RiPPs), including lanthipeptides and lassopeptides, suggesting a multifaceted antimicrobial mechanism. Conclusions: These findings position ExAFs, particularly E10, as promising, peptide-rich, bio-based antimicrobial candidates for food safety or therapeutic applications. The co-occurrence of RiPP analogs and secondary metabolites in the formulation suggests the potential for complementary or multi-modal bactericidal effects, positioning these compounds as promising eco-friendly alternatives for combating MDR pathogens. Full article

Background/Objectives: The rise in urinary tract infections caused by multidrug-resistant (MDR) bacteria presents a serious public health challenge across the Balkans, a region already burdened by aging populations, healthcare resource limitations, and fragmented antimicrobial surveillance systems. Methods: This review explores the epidemiology, risk factors, and consequences of MDR UTIs, particularly in the context of the COVID-19 pandemic, which significantly accelerated antimicrobial resistance (AMR) due to widespread, inappropriate antibiotic use. Results: The paper discusses region-specific data on resistance trends, highlights the gaps in diagnostic infrastructure, and evaluates emerging clinical strategies including antimicrobial stewardship (AMS), rapid diagnostic technologies, novel antibiotics, and non-antibiotic alternatives such as bacteriophage therapy and vaccines. Conclusions: Policy recommendations are provided to strengthen surveillance, promote evidence-based treatment, and ensure equitable access to diagnostic and therapeutic tools. A multidimensional and regionally coordinated response is essential to curb the MDR UTI burden and safeguard public health across the Balkans. Full article

Background: Hansen’s disease or leprosy is one of the 21 neglected tropical diseases (NTDs). In Ecuador, leprosy is considered eliminated as a public health problem; however, new cases are reported annually. Additionally, Mycobacterium leprae infection was detected in nine-banded armadillos across the country, suggesting a potential zoonotic reservoir. This literature review aims to provide an updated overview of the epidemiological situation of leprosy in Ecuador, identify knowledge gaps, and outline research priorities to support the development of a comprehensive national strategy for achieving zero autochthonous cases. Methods: This article analyses the current situation of leprosy in Ecuador based on international and national publications. A retrospective literature search using five international, regional, and national publications on leprosy published between 1954 and 2024 (70 years) with no restriction on language or publication date, was performed. Findings: Our review identified 28 publications with the earliest article dating back to 1954. Of these, 14 were published in international journals, 15 (53.6%) were in Spanish. Four nationwide studies documented leprosy cases across Ecuador’s three continental regions (Coast, Andes, and Amazon) with a predominance in the tropical coast. No cases have been reported from the Galápagos Islands. From 1983, Ecuador started multi-drug therapy. Data from the Ministry of Public Health (MoH) system identified 1539 incident cases, showing a significant decline in new cases from 2000 to 2024, with no cases in children. New cases detection rate by 100,000 inhabitants was 0.51 in 2019 according to the World Health Organization (WHO). No study has genotyped the Mycobacterium spp. in human cases, other animal species, or environment. According to the MoH, multibacillary leprosy accounts for 78.95% of diagnosed cases, with confirmation based on Ziehl–Neelsen staining and histopathology. No survey has assessed disabilities, knowledge, attitudes, and practices (KAP) or stigma related to leprosy. Research is needed on transmission routes, Mycobacterium genotyping, genetic susceptibility, and antibiotic resistance. BCG vaccination coverage fell to 75.3% in 2021. Cases are currently diagnosed and treated on an outpatient basis in large hospitals. Conclusions: This comprehensive review highlights persistent gaps in leprosy research and critical information, despite seven decades of documented cases in Ecuador. The disease is still endemic across the country, particularly at subnational level in the subtropics and tropics of the Pacific coast and the Amazon. There is a need for nationwide epidemiological research on reservoirs and the environment applying the One Health concept. Increased laboratory facilities and readily available official data are required to improve our understanding of leprosy in Ecuador. Strengthening community-level efforts is essential for Ecuador to meet the targets of the “WHO’s Towards Zero Leprosy: Strategy 2021–2030.” Full article

Recurrent urinary tract infections (UTIs) pose a significant clinical challenge in both human and veterinary medicine, due to antibiotic-resistant and biofilm-forming bacteria. We hypothesized that high glucose levels in diabetic animals enhance biofilm formation and reduce antibiotic efficacy, promoting infection persistence. This study analyzed Escherichia coli from a diabetic female Labrador Retriever with recurrent UTIs over 18 months, focusing on antimicrobial resistance, biofilm-forming capacity, and genomic characterization. Most isolates (9/11) were resistant to ampicillin and fluoroquinolones. Whole genome sequencing of six selected isolates revealed that they belonged to the multidrug-resistant ST1193 lineage, a globally emerging clone associated with persistent infections. Phylogenetic analysis revealed clonal continuity across six UTI episodes, with two distinct clones identified: one during a coinfection in the second episode and another in the last episode. High-glucose conditions significantly enhanced biofilm production and dramatically reduced antibiotic susceptibility, as evidenced by a marked increase in minimum biofilm inhibitory concentrations (MBICs), which were at least 256-fold higher than the corresponding minimum inhibitory concentration (MIC). Sulfamethoxazole–trimethoprim demonstrated the strongest antibiofilm activity, though this was attenuated in glucose-supplemented environments. This research highlights the clinical relevance of glucosuria in diabetic patients and emphasizes the need for therapeutic strategies targeting biofilm-mediated antibiotic tolerance to improve the management of recurrent UTIs. Full article

Antimicrobial resistance is a critical global health issue exacerbated by biofilm-associated infections that often resist conventional therapies. Photodithazine-mediated antimicrobial photodynamic therapy (PDZ-aPDT) has emerged as a promising alternative, demonstrating a broad-spectrum antimicrobial efficacy against multidrug-resistant bacteria and fungi, including those in biofilms. This systematic review evaluates the efficacy, safety, and clinical applications of PDZ-aPDT by synthesizing evidence from preclinical and clinical studies. Databases including PubMed, Embase, Scopus, and Cochrane were systematically searched, resulting in the inclusion of 13 studies for qualitative analysis. PDZ-aPDT consistently reduced the microbial burden in various models, including oral candidiasis, denture stomatitis, acne, and infections related to medical devices. Synergistic combinations with conventional antimicrobials and adjunctive therapies (e.g., DNase I) further enhanced its effectiveness. However, the evidence base remains limited by methodological variability, small sample sizes, and short follow-up periods. Future research should focus on rigorous clinical trials with standardized protocols and extended follow-up to establish definitive efficacy and safety profiles, facilitating a broader clinical implementation in combating antimicrobial resistance. Full article

The concerning increase in respiratory infections that are resistant to multiple drugs has led to a growing interest in bacteriophage therapy as a potential alternative to conventional antibiotics. Effective phage delivery to the lungs, however, presents several formulation and stability issues, particularly for inhalation-based methods. This review highlights current developments in the creation of dry powder formulations that can be inhaled for pulmonary phage therapy, with a focus on encapsulation methods based on nanoparticles, such as solid lipid nanoparticles (SLNs) and polymer-based nanoparticles. These carriers enhance the aerodynamic characteristics of phages, making them suitable for deep lung deposition, while also protecting them during processing and storage. Several drying methods have been investigated to create powders with optimal morphologies, porosity, and dispersibility, including spray drying and spray freeze drying. The review also emphasizes how the phage morphotype affects stability, especially when nebulization stress is present. Furthermore, the advantages of nanoparticle matrices are confirmed by the reduced viability loss (usually< 0.5 log PFU) of encapsulated phages. Standardizing production processes, scaling up, and ensuring regulatory compliance remain challenging despite encouraging preclinical results. The combination of phage therapy with nanotechnology creates new avenues for the utilization of inhalable delivery methods to treat multidrug-resistant pulmonary infections. To translate these novel formulations from preclinical development to clinical application, sustained multidisciplinary collaboration across pharmaceutical sciences, microbiology, and clinical pharmacology is essential. Full article

Multi-drug resistance in human bacterial pathogens has become a significant challenge for global healthcare this century, mainly due to the widespread misuse of antibiotics worldwide. As a result, millions of people have been affected by multi-drug-resistant bacterial infections. The antibiotic development pipelines cannot cope with the need to produce new antibiotics. Therefore, more productive antibiotic development methods must be invented. This paper presents an entirely rational approach for antibacterial drug discovery based on chimeric antisense oligonucleotide targeting (ASO) of the adenylate kinase mRNA in Staphylococcus aureus. The ASO is delivered into the bacteria via the cell-penetrating oligopeptide pVEC. The pVEC-ASO1 exhibits a bactericidal effect against Staphylococcus aureus, with a 50% minimal inhibitory concentration of 500 nM. The pVEC-ASO1 has a 98% survivability rate at the same concentration on cell lines. These findings strongly suggest that this chimeric ASO is a promising antibacterial drug candidate. Moreover, this is the fifth bacterial mRNA we have successfully targeted with pVEC-ASOs, providing further evidence for the efficiency of our approach. In contrast to the previous four targets, riboswitches residing in the 5′-untranslated region, we target the coding part of mRNA found in bacteria. That suggests that our approach may have much broader therapeutic applications. Full article

The southern pudu (Pudu puda) faces significant threats from anthropogenic activities and infectious diseases. Using whole-genome sequencing (WGS) and forensic microbiology research, we describe a triple bacterial co-infection in a southern pudu impacted by wildfire disasters. The deer presented infected burn wounds on the extremities and dog bite wounds in the lumbosacral region, from which a multidrug-resistant CTX-M-1-producing Escherichia coli sequence type (ST) ST224 and a Klebsiella oxytoca ST145 were isolated, respectively. The patient died 13 days after admission in a wildlife rehabilitation center. During the necropsy, a sample from intracardiac blood was collected, and WGS analyses confirmed systemic dissemination of an E. coli ST224 clone. The broad virulome (adhesins, invasins, toxins, and immune evasion genes) and resistome against beta-lactams (bla_CTX-M-1), aminoglycosides [aac(3)-IId, aph(3′)-Ia, aph(3″)-Ib, aph(6)-Id], macrolides [mph(A)], sulfonamides (sul2), trimethoprim (dfrA17), and fluoroquinolones (gyrA and parC mutations) of E. coli ST224 contributed to the treatment failure and death of the wild animal. Additionally, an oval nodule was identified in the abdominal cavity caused by Acinetobacter baumannii ST1365, the first WGS-confirmed report in wildlife. This study highlights the value of applying forensic microbiology and WGS to investigate and understand One Health pathogens threatening wildlife impacted by natural and anthropogenic disasters. Full article

Background/Objectives: Infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa are steadily increasing, thus the discovery and development of new and effective agents are needed. Antimicrobial peptides (AMPs) are a heterogeneous group of innate defense system peptides with broad antimicrobial activity. In this study, 17 AMPs were tested, identifying CAP-18, a cathelicidin-based compound, as the most active. CAP-18 was optimized by synthesizing structural derivatives, which were selected for further studies based on their activity against a collection of MDR and colistin-resistant P. aeruginosa strains. Methods: AMPs collection was initially tested against different P. aeruginosa strains, identifying CAP-18 as the most active. CAP-18 derivatives were synthetized and assessed by the Minimum Inhibitory Concentration (MIC), time-kill kinetics, cytotoxicity against human cell lines, hemolytic activity, and therapeutic index (IC₅₀/MIC₉₀). The mechanism of action was assessed by Transmission Electron Microscopy (TEM), and in vivo efficacy was determined through a murine skin infection model. Results: CAP-18 and D-CAP-18 had a MIC₉₀ of 4 and 2 μg/mL, respectively, whereas CAP-18₃₁ and D-CAP-18₃₁ presented MIC₉₀ values of 16 mg/L. The shorter derivatives of CAP-18 showed a lower activity. Time-kill curves revealed a fast bactericidal effect. These derivatives showed low toxicity against different human cell lines and low hemolysis, resulting in a wide therapeutic index (IC₅₀/MIC₉₀), with D-CAP-18 having the best therapeutic index (137.4). TEM provided insight into the mechanism of action, revealing bacterial membrane damage. In vivo studies of both CAP-18 and D-CAP-18 showed good activity with a 3 log decrease compared to the infected control group. Conclusions: Among the investigated four peptides, D-CAP-18 is the most promising candidate to treat skin infections caused by MDR P. aeruginosa since it shows potent activity both in vitro and in vivo, and a high therapeutic index. Full article