Search Results (730)

Background: Environmental surfaces are key reservoirs for pathogen transmission, with the survival of bacteria on fomites influenced by factors such as temperature, humidity, and microbial interactions. This study aimed to determine microbial surface contamination and to determine the antimicrobial resistance profile of bacteria isolated from the indoor surface where the presence of cockroaches was observed in households of the Greater Letaba Municipality (GLM), South Africa. Methods: Swab samples were collected from kitchen countertops and food storage areas with visible cockroach activity. Bacteria were isolated and identified using standard microbiological methods, and antimicrobial susceptibility testing (AST) was conducted with the Vitek^® Automated 2 system. Results: Of the 120 samples collected, 82 (68%) showed bacterial growth, resulting in 190 isolates. The majority of isolates (93%) were Gram-negative, comprising Klebsiella, Pseudomonas, Enterobacter, Escherichia, Serratia, Stenotrophomonas, Pantoea, Raoultella, and Salmonella species, with 98% demonstrating multidrug resistance (MDR) to multiple antibiotics. Resistance was particularly high against gentamicin (94%), fluoroquinolones (88%) and amikacin (77%). Among Gram-positive isolates, all belonged to the Enterococcus species, with 22% being resistant to one or two of the tested antimicrobial agents and 78% exhibiting MDR. Conclusions: The study revealed a high prevalence of antibiotic resistance in both Gram-positive and Gram-negative bacteria isolated from household surfaces. The spread of antibiotic-resistant pathogens via environmental surfaces presents a significant risk to human health, safety, and well-being. Full article

Disinfectant tolerance in bacteria may be related to exposure to subinhibitory concentrations of disinfectants, which may activate efflux pumps capable of expelling antimicrobial compounds. The aim of this study was to evaluate the impact of disinfection on the presence of efflux pump genes and the resistance profile of Escherichia coli from commercial laying farms employing different disinfection protocols. The emrE, qacE, qacEΔ1, qacH, sugE(c), ydgE, ydgF, and class 1 integron (intl1) genes were investigated using PCR. Susceptibility to 17 antibiotics was assessed, including β-lactams, fluoroquinolones, aminoglycosides, and tetracyclines. Disinfectant exposure was significantly associated with higher frequencies of qacE and qacH, and a reduced frequency of ydgF. Moreover, resistance to ampicillin, trimethoprim–sulfamethoxazole, and doxycycline was significantly more frequent in E. coli isolated from chickens exposed to disinfectants. These findings indicate that disinfectant use can select for E. coli carrying efflux pump genes and resistance genes, favoring the survival and dissemination of tolerant and resistant strains in poultry production. Continuous monitoring and the development of disinfection strategies that minimize selective pressures are crucial for limiting the spread of antimicrobial resistance at the animal–human–environment interface. Full article

Background/Objectives: Antimicrobial resistance (AMR) is a major global health threat. In patients undergoing cataract surgery, AMR complicates infection control, particularly efforts to reduce the risk of endophthalmitis—a rare but severe postoperative complication. This article reviews country-specific strategies for endophthalmitis prevention, focusing on antimicrobial use. Methods: Ophthalmology experts from 10 countries contributed national perspectives on infection prevention. Official guidelines served as the primary basis for analysis; when unavailable, expert opinion and routine clinical practice were considered. Results: Routine preoperative antibiotic use is uncommon in 6 out of 10 countries. Instead, artificial tears and bacteriostatic or bactericidal treatments are frequently employed. One country allows optional antibiotic use, while 3 include it in routine preoperative care. For intraoperative management, antisepsis with 5–10% povidone-iodine is standard practice in 9 countries. Intracameral cefuroxime (typically 1 mg/0.1 mL) is widely used in 7 countries and considered essential in most countries. Postoperatively, broad-spectrum topical antibiotics, primarily fluoroquinolones, are typically prescribed, often as fixed-dose combinations with corticosteroids (8 countries), although duration and regimens vary. Conclusions: Despite national differences, povidone-iodine, intracameral cefuroxime, and topical fluoroquinolones are widely used. Preoperative antibiotic use varies, while postoperative regimens are more consistent. These practices reflect local AMR patterns, regulations, and available healthcare resources. Although broad-spectrum agents are generally preferred, they raise concerns about resistance. Tailoring prophylactic strategies to local microbiological profiles and limiting the duration of antibiotic therapy are key to balancing efficacy and stewardship. An individualized, evidence-based approach is essential to reduce endophthalmitis risk and address AMR challenges. Full article

Non-tuberculous mycobacteria (NTM) comprise more than 190 species capable of causing severe pulmonary, lymphatic, cutaneous, and disseminated infections, particularly in immunocompromised populations. Over the past two decades, the global incidence of NTM infections has risen steadily, underscoring an urgent unmet medical need. Treatment remains highly challenging due to intrinsic antimicrobial resistance and the requirement for prolonged multidrug regimens that are often poorly tolerated and associated with unsatisfactory outcomes. At the same time, the development of novel therapies has lagged behind other disease areas, hindered by the high costs of antimicrobial drug discovery and the relatively low commercial return compared with treatments for chronic conditions. Over the past decade, discovery and development have diversified across novel small molecules, next-generation analogues of existing classes, and adjunctive or host-directed strategies. While most candidates remain preclinical, several agents have advanced clinically in other infections, including gepotidacin (topoisomerase inhibitor; FDA-approved 2025 for urinary tract infection (UTI)), sulbactam–durlobactam (DBO β-lactamase inhibitor; FDA-approved 2023 for Acinetobacter baumannii complex), and contezolid, supporting repurposing opportunities for NTM. Conversely, SPR720 (gyrase B prodrug) was suspended after not meeting its Phase 2 endpoint in 2024, underscoring translational risk. Overall, the NTM pipeline is expanding, with near-term progress most likely from repurposed agents and optimised combinations, alongside earlier-stage candidates that target biofilms or resistance mechanisms. This review aims to provide a critical and up-to-date overview of emerging antimicrobial strategies against NTM, highlighting recent advances, translational challenges, and opportunities to accelerate the development of effective therapeutics. Full article

Antibiotic stereoisomers as components of medicines are typically characterized by different biological activities. Because pharmaceuticals can include a racemic mixture of stereoisomers, monitoring of all forms is required. One contaminant of food products, antibiotic ofloxacin (OFL), as a chiral compound, has two enantiomers—the biologically active S-isomer and less active R-isomer. In this study, a sensitive immunochromatographic test system for simultaneous enantiospeсific detection of the two OFL isomers was developed for the first time. For this, polyclonal antibodies were produced, and conditions for a double lateral flow immunoassay (LFIA) were selected and optimized so that the cross-reactivity with another enantiomer was negligible. The LFIA was performed in a competitive format with gold nanoparticles as a label for secondary antibodies. The achieved LODs/cutoffs were 0.001/10 and 0.007/30 ng/mL for S-OFL and R-OFL detection, respectively; the assay procedure took only 15 min. A double LFIA was performed to detect S-OFL and R-OFL in milk with minimal sample pretreatment; the recoveries were 85–95%. The developed test system is an effective tool for the selective detection of both isomers of OFL, allowing for the avoidance of false negative results. This immunochromatographic approach can be promising for the control of other optically active food toxicants. Full article

Background/Objectives: The COVID-19 pandemic accelerated the inappropriate use of antibiotics, amplifying the global threat of antimicrobial resistance (AMR), particularly in resource-limited healthcare settings. This study investigated AMR patterns in a tertiary care hospital, focusing on the impact of the COVID-19 pandemic on invasive bacterial pathogens. Methods: This retrospective observational study was conducted at the University Clinical Centre of the Republic of Srpska, analyzing AMR data from invasive bacterial isolates collected between 2015 and 2024, and assessing correlations between antibiotic utilization and resistance patterns during the study periods. Results: Among 4718 invasive bacterial isolates, Acinetobacter spp. (26.7%) and K. pneumoniae (20.8%) were the most prevalent. A significant increase in invasive isolates was observed during the COVID-19 period, particularly for K. pneumoniae (p = 0.003), P. aeruginosa (p = 0.017), Acinetobacter spp. (p = 0.013), and E. faecium (p = 0.028). The highest multidrug-resistant (MDR) rates were observed in Acinetobacter spp. (97% during COVID-19) and K. pneumoniae (>80% post-COVID-19). Resistance increased significantly in K. pneumoniae to cephalosporins, fluoroquinolones, and carbapenems, and in P. aeruginosa and Acinetobacter spp. to carbapenems, while P. aeruginosa resistance to aminoglycosides declined. Strong correlations were found between carbapenems use and Acinetobacter spp. resistance (r = 0.861, p = 0.001), and vancomycin use and E. faecalis resistance (r = 0.798, p = 0.006). Moderate correlations were also observed between carbapenems use and resistance of K. pneumoniae and P. aeruginosa. Conclusions: These findings highlight the profound impact of the COVID-19 pandemic on AMR dynamics, particularly among Gram-negative pathogens, and underscore the urgent need for strengthened antimicrobial stewardship and targeted surveillance to curb the spread of MDR pathogens, especially in resource-limited hospitals. Full article

Antimicrobial resistance (AMR) is a growing global health concern with profound implications for ophthalmology, where it compromises the management of ocular infections such as bacterial keratitis, conjunctivitis, endophthalmitis, and postoperative complications. Resistance in common ocular pathogens, including Staphylococcus aureus (S. aureus), Streptococcus pneumoniae (S. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa), and coagulase-negative staphylococci (CoNS) emerge through genetic mutations, horizontal gene transfer, and biochemical mechanisms such as enzymatic degradation, target modification, efflux pumps, and reduced membrane permeability. Biofilm formation further complicates eradication on the ocular surface and interior. The key drivers of resistance include inappropriate or prolonged topical antibiotic use, routine prophylaxis in ocular surgery, subtherapeutic dosing, and cross-resistance with systemic antimicrobials. The rise in multidrug-resistant strains, particularly methicillin-resistant S. aureus, fluoroquinolone-resistant P. aeruginosa, and drug-resistant S. pneumoniae has been linked to delayed treatment response, increased healthcare costs, and sight-threatening outcomes. Recent advances in rapid diagnostics, molecular assays, and point-of-care testing support earlier and more precise detection of resistance, enabling timely therapeutic decisions. Promising strategies to address AMR in ophthalmology include antimicrobial stewardship, novel drug delivery platforms, and alternative approaches such as bacteriophage therapy and antimicrobial peptides. Emerging tools, including genomic surveillance, artificial intelligence (AI)-driven resistance prediction, and personalized antimicrobial regimens, further expand opportunities for innovation. Collectively, this review synthesizes current evidence on AMR in ocular disease, summarizing patterns of resistance, underlying mechanisms, and clinical consequences, while highlighting strategies for mitigation and underscoring the need for global awareness and collaboration among clinicians, researchers, and policymakers to safeguard vision. Full article

Background: In recent years, there has been a significant increase in cases of tularemia, a rare zoonotic disease caused by Francisella tularensis, in Europe. Methods: To investigate the epidemiological, clinical, and therapeutic characteristics of tularemia patients in Germany, we performed a retrospective evaluation of tularemia cases treated between 2010 and 2025 at selected treatment centers of the Permanent Working Group of Competence and Treatment Centers for High Consequence Infectious Diseases (STAKOB) at the Robert Koch Institute. Results: A total of 65 patients (median age: 48.5 years; 66.2% male) were identified. Most common manifestation was ulceroglandular (70.7%), followed by oropharyngeal (13.8%), pulmonary (10.8%), oculoglandular (7.7%), typhoidal (4.6%), and meningitic (4.6%). Serological confirmation of the diagnosis was achieved in all patients (90.8% ELISA, 46.2% Western blot). PCR-based direct pathogen detection was successful in 26.2%. Bloodstream infection was detected in 4.6%. Median incubation period was 7 days (IQR: 4–10), with fever being the most common symptom in 96.9% and lymphadenopathy in 46.2%. Median time to recovery was 56 days (IQR: 37–80) in patients diagnosed and treated early (≤3 weeks after symptom onset), compared to 84 days (IQR: 66–182) in patients with late diagnosis (>3 weeks after symptom onset; p = 0.015). Empirical therapy with beta-lactam antibiotics was initiated in 49.2% of cases. Following suspicion of tularemia, 96.9% received recommended treatment with fluoroquinolones, tetracyclines, or aminoglycosides. Conclusions: Delayed diagnosis and inappropriate initial therapy can significantly prolong disease courses and increase morbidity. Early treatment with effective antibiotics, considering the intrinsic beta-lactam resistance of Francisella tularensis, leads to faster recovery. Full article

Fluoroquinolones (FQs) are ubiquitously present in aquatic environments, garnering considerable research attention. Ciprofloxacin (CIP), the most extensively utilized FQ antibiotic, features high aqueous residual levels and ranks among the most frequently detected antibiotics in environmental matrices. It also acts as a precursor of disinfection byproducts (DBPs). In recent years, ultraviolet-based combined disinfection has been widely used. This study investigated the removal efficiency of CIP and the identification of DBPs under four disinfection systems: UV irradiation, UV/PS, UV/CaO₂, and UV/H₂O₂. Microcystis aeruginosa (M. aeruginosa), a dominant algal species in eutrophic freshwater ecosystems, was selected as the test organism to investigate the toxicity of DBPs generated via distinct disinfection approaches. The results demonstrated significant variations in CIP removal efficiency among the four disinfection methods. The removal rates reached 93–99% under UV/H₂O₂, UV/CaO₂, and UV/PS, while single UV irradiation achieved only 87%. Sixteen DBPs were identified during the process. The DBPs produced under different disinfection methods exhibited varying inhibitory effects on M. aeruginosa growth. DBPs formed under the UV/H₂O₂ and UV/CaO₂ systems displayed the strongest inhibition, with maximum inhibition rates of 42.1% and 36.2% within 12 days, respectively. In contrast, DBPs formed under the UV/PS and UV systems showed weaker inhibition (25.3% and 22.1%, respectively), and their inhibitory effects decreased at higher disinfection byproduct (DBP) concentrations. The results indicate that while combined UV disinfection enhances CIP removal, it may also increase the toxicity of the resulting DBPs to aquatic organisms. Overall, the UV/PS process demonstrated the highest degradation efficiency for CIP and produced disinfection byproducts (DBPs) with lower toxicity, making it the most effective and environmentally friendly method for treating water contaminated with ciprofloxacin. Full article

Swine respiratory disease (SRD) is a complex interaction whereby viral infection predisposes the host to secondary bacterial pulmonary invasion, which may be fatal. Antimicrobial agents remain an important therapy and serve to reduce morbidity and mortality in treated animals. Pradofloxacin is the newest of the veterinary antibiotics to be approved to treat SRD. It is a dual-targeting fluoroquinolone with in vitro and clinical activity against Gram-negative and -positive bacteria, along with atypical agents including anaerobes. In this study, we compared the killing of Actinobacillus pleuropneumoniae, Pasteurella multocida, and Streptococcus suis by pradofloxacin and comparator antibiotics in a 3 h kill assay, using four clinically relevant drug concentrations. Pradofloxacin was bactericidal against the three pathogens, with kill rates ranging from 94.4 to 99.9% (A. pleuropneumoniae) following 15–20 min of exposure to the maximum serum and maximum tissue drug concentration. For P. multocida, the kill rates were 68.7–96.9% following 5–30 min of drug exposure at the maximum serum drug concentration, and 91.7% following 5 min of drug exposure at the maximum tissue drug concentration. For S. suis, pradofloxacin killed 92.4–99.4% and 71.6–97.1% of cells following 60–180 min of drug exposure at the maximum serum and maximum tissue drug concentration, respectively. Pradofloxacin appears to be an important addition to the drugs currently available for treating SRD. Full article

The occurrence of antibiotic residues in the environment is of concern not only because of their contribution to the spread of bacterial resistance, but also due to their possible toxicity to non-target organisms. In this study, the aquatic environmental toxicity of ciprofloxacin (CIP) and sulfamethoxazole (SMX) was assessed in the following model organisms: Daphnia magna and Artemia salina (embryonic and immobilisation test with a 10-d follow-up), Phaeodactylum tricornutum (algal growth inhibition test), and Spirodela polyrhiza (duckweed growth inhibition test). Results showed that among the two saltwater organisms, A. salina was insensitive to both antibiotics, whilst P. tricornutum responded only to SMX with an EC₅₀ of 2.7 mg L⁻¹. In freshwater species, D. magna embryos were more sensitive than juveniles to SMX (EC₅₀ 53.8 and 439.2 mg L⁻¹, respectively), whereas the opposite trend was observed for CIP (EC₅₀ 95.9 and 15 mg L⁻¹, respectively). S. polyrhiza confirmed the remarkable sensitivity of aquatic plants to fluoroquinolones, with EC₅₀ values between 0.28 and 0.34 mg L⁻¹ depending on the endpoint considered. Notably, this species was also more sensitive to SMX than expected, with EC₅₀ values between 1.5 and 2.5 mg L⁻¹, which are an order of magnitude lower than those typically obtained with Lemna spp. exposed to sulphonamides. Considering the high environmental input of these antibiotics from both human and veterinary treatments, adverse effects on aquatic plants cannot be excluded, potentially leading to ecosystem-level consequences. Full article

Background: The escalating burden of antimicrobial resistance (AMR) poses a critical threat to public health in Pakistan, with rates of high antibiotic consumption and limited standardized surveillance on AMR rates. Our study aimed to carry out a multicentric surveillance of AMR to generate regional antibiograms for Northern Punjab, Pakistan, to guide empirical antimicrobial therapy and stewardship efforts. Methods: A laboratory-based, retrospective cross-sectional study was conducted over a six-month period across three tertiary care hospitals. Socio-demographic, clinical, and microbiological data (including specimen type and antibiotic prescription rates) were collected from N = 485 patients with confirmed bacterial infections. Antimicrobial susceptibility testing was performed based on Clinical Laboratory Standards Institute (CLSI) recommendations. Statistical analyses were carried out using SPSS v.22.0. Results: In our study setting, Gram-positive bacteria were common causes (60.0%) of infections, with Staphylococcus aureus (12.2%) and Streptococcus pneumoniae (10.3%) being the most relevant. Among Gram-negative bacteria (40.0%), Escherichia coli (14.0%) and Pseudomonas aeruginosa (5.8%) were shown to be important pathogens. Overall, 25.0% of S. aureus isolates were methicillin-resistant (MRSA), while ~30% of E. coli showed resistance to third-generation cephalosporins (3GCs). Enterobacterales species had highly variable susceptibility rates (40–70%) for fluoroquinolones. Meropenem and vancomycin/linezolid retained high efficacy (>90%) against most Gram-negative and Gram-positive isolates, respectively. In all healthcare settings studied, ceftriaxone was the most frequently prescribed antibiotic. Conclusions: High levels of resistance against first-line antibiotics were noted in our setting of Northern Punjab, Pakistan, underscoring the critical need for robust antimicrobial stewardship programs, tailored to local institutional contexts, capabilities, and needs. The regional antibiogram developed based on our data may provide vital evidence for informing local empirical treatment guidelines, which need to be continuously updated. Full article

Background: The COVID-19 pandemic profoundly affected healthcare delivery and antibiotic prescribing, raising concerns about increasing antimicrobial resistance. This study investigated seven-year trends in bacterial resistance, underlying resistance mechanisms, and antibiotic consumption in COVID-19 and non-COVID-19 units at a tertiary hospital in Slovakia. Methods: A retrospective cohort analysis (2018–2024) was conducted using clinical isolates of Klebsiella sp., Acinetobacter sp., and P. aeruginosa. Data on hospitalizations, resistance profiles, resistance mechanisms, and standardized antibiotic use were compared between COVID-19 and non-COVID-19 departments. Results: Hospitalizations markedly decreased in COVID-19 units, while pathogen occurrence—particularly of Acinetobacter sp.—was substantially higher compared with non-COVID-19 units. Resistance in Klebsiella sp. shifted from extended-spectrum beta-lactamase production to carbapenemase production. Acinetobacter sp. remained highly resistant, although some declines were observed in ceftazidime and gentamicin resistance. P. aeruginosa showed a gradual reduction in resistance, notably to piperacillin/tazobactam and imipenem. Antibiotic consumption was consistently higher in COVID-19 units, particularly for broad-spectrum beta-lactams and carbapenems, whereas fluoroquinolone use decreased over time. Clinically effective treatment options were considerably fewer in COVID-19 units, often limited to colistin. Conclusions: COVID-19 units experienced greater pathogen burden, higher broad-spectrum antibiotic exposure, and increased prevalence of critical resistance mechanisms. Tailored antimicrobial stewardship and infection prevention, and control are essential to reduce selective pressure and preserve last-line antibiotics. Full article

The microbiome of howler monkeys is being studied as a potential indicator of forest health. This explorative research aimed to analyze the microbiome, antibiotic resistance genes, and virulence factors of the howler monkey (Alouatta seniculus) in two Colombian Andean forests. A total of six samples were collected from three monkeys in two different forests. The samples were processed and sequenced using 16S rRNA V3-V4 metabarcoding and shotgun metagenomics. No significant differences in microbial diversity were observed between locations. A total of 43 possible resistance genes were identified, 11 of which were associated with plasmids, while 66 virulence genes were detected. The bacterial genera with the highest number of resistance genes were Escherichia and Enterococcus, whereas Escherichia and Citrobacter exhibited the highest number of virulence factors. The bacteria were predominantly resistant to fluoroquinolones, macrolides and beta-lactams, while adherence was the dominant virulence mechanism. This exploratory study suggests that the locations provide similar habitats for howler monkeys and that the presence of resistance genes is primarily due to intrinsic bacterial resistance mechanisms and natural resistance in wild populations despite the environmental presence of bacterial genera with resistance genes and virulence factors. However, acquisition through interaction with domestic animals was not evaluated. Full article

Background: Fluoroquinolone (FQ) resistance in Escherichia coli (E. coli) undermines empiric therapy and often coincides with multidrug resistance (MDR). Because sequencing is not routinely available in many laboratories, we evaluated a phenotype-first, sequencing-independent diagnostic framework deployable on standard platforms. Methods: We profiled 45 archived E. coli isolates for susceptibility (Clinical and Laboratory Standards Institute [CLSI]-guided), extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase (AmpC) phenotypes, MDR, and multiple-antibiotic resistance (MAR) indices. Ten founders (five FQ-susceptible [FQ-S], five low-level resistant [LLR]) seeded 20 parallel lineages exposed to stepwise ciprofloxacin. We tracked minimum inhibitory concentrations (MICs), collateral resistance, growth kinetics, and biofilm biomass using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification, automated and reference antimicrobial susceptibility testing (AST), growth-curve analysis, and crystal violet microtiter assays. The intended use is a sequencing-independent workflow for routine laboratories—especially where whole-genome sequencing is not readily available—working with archived or prospective clinical E. coli. This workflow is best applied when local FQ nonsusceptibility threatens empiric reliability; inputs include standard ID/AST with simple growth and biofilm assays. Primary outputs include: (i) MIC trajectories with time to high-level resistance (HLR), (ii) ΔMAR-summarized collateral resistance with class-level susceptible-to-resistant conversions, and (iii) concise fitness/biofilm summaries to guide empiric-policy refresh and early de-escalation. Results: At baseline, ciprofloxacin nonsusceptibility was 40.0%; ESBL and AmpC phenotypes were confirmed in 28.9% and 15.6%, respectively; 46.7% met the MDR definition; and the median MAR index was 0.29. During evolution, 70% of lineages reached HLR (MIC ≥ 4 μg/mL), with earlier conversion from LLR versus FQ-S founders (median 7 vs. 11 passages). Collateral resistance emerged most often to third-generation cephalosporins (3GCs), trimethoprim–sulfamethoxazole, and tetracyclines, while carbapenem activity was preserved. MAR increased in parallel with rising MICs. Resistance acquisition imposed modest fitness costs (slightly reduced growth rates and longer lag phases) that were partly offset under subinhibitory ciprofloxacin, whereas biofilm biomass changed little. Conclusions: this phenotype-first, routine-laboratory workflow rapidly maps FQ resistance and clinically relevant co-selection in E. coli. In high-resistance settings, empiric FQ use is difficult to justify, and MAR trends provide practical co-selection signals for stewardship. This reproducible framework complements genomic surveillance and is directly applicable where sequencing is unavailable. Full article