Antimicrobial Resistance is a critical health challenge in the African Region. This papefactors and review of evidence generated through WHO-supported monitoring and surveillance tools to describe progress in AMR governance architecture and monitoring uptake in addressing antimicrobial resistance in the WHO African region over the past decade, highlight key enabling factors, and propose actions required to address persisting challenges. We reviewed country reports on the implementation of antimicrobial resistance national action plans using the most recent 2024 Tracking Antimicrobial Resistance Country Self-Assessment Survey with multi-sectoral and human health specific indicators, alongside data from the Global AMR/Use Surveillance System databases. The number of countries with National Action Plans on antimicrobial resistance under the One Health approach increased from 2 (4.3%) in 2015 to 47 (100%) in 2024. Between 2017 and 2024, the number of countries with national guidelines for appropriate antimicrobial use and antimicrobial stewardship programmes increased from 10 (21.3%) to 20 (42.6%). Multisectoral coordination mechanisms rose from 13 (27.7%) in 2015 to 41 (87.2%) in 2024. During the same period, countries conducting nationwide AMR awareness campaigns grew from 2 (4.3%) to 16 (34%), and participation in Global AMR/Use Surveillance System expanded from 7 (14.9%) to 41 (87.2%). Success factors driving this progress include country endorsement and adaptation of global and regional antimicrobial resistance strategies, stronger collaboration among stakeholders including United Nations agencies, civil society, and partners, and use of platforms like Tracking Antimicrobial Resistance Country Self-Assessment Survey and Global AMR/Use Surveillance System to generate data for decision-making. Moving forward, collective efforts from all stakeholders are essential to consolidate progress and contribute to global health security, achieve Universal Health Coverage and Sustainable Development Goals. Additionally, future AMR research agenda should focus on measuring the impact of AMR interventions and developing new AMR prevention and control strategies.
Background Dental caries and oral candidiasis are among the most common oral diseases and are primarily associated with Streptococcus mutans and Candida albicans. Growing concerns regarding antimicrobial resistance and the adverse effects of synthetic antimicrobial agents have increased interest in plant-derived alternatives. This study evaluated and compared the antimicrobial efficacies of aqueous extracts of Abrus precatorius and Achyranthes aspera against Streptococcus mutans and Candida albicans. Methodology An in vitro experimental study was conducted using aqueous extracts from the leaves of Abrus precatorius and Achyranthes aspera. The antimicrobial activity against Streptococcus mutans (ATCC 25175) and Candida albicans (ATCC 10231) was assessed using the agar well diffusion method. Chlorhexidine and nystatin served as positive controls for antibacterial and antifungal testing, respectively, and distilled water served as the negative control. Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method. Data were analyzed using one-way analysis of variance followed by Tukey's post-hoc test and independent-samples t-test. Results Significant differences in antimicrobial activity were observed among the groups (p < 0.001). Against Streptococcus mutans, Abrus precatorius demonstrated a larger mean zone of inhibition (18.42 ± 1.58 mm) than Achyranthes aspera (15.16 ± 1.47 mm), although chlorhexidine exhibited the greatest antibacterial activity (24.31 ± 1.32 mm). Similarly, against Candida albicans, Abrus precatorius produced a larger inhibition zone (16.87 ± 1.36 mm) than Achyranthes aspera (13.92 ± 1.41 mm), whereas nystatin showed the highest antifungal activity (22.74 ± 1.24 mm). Abrus precatorius also demonstrated significantly lower MIC values against both microorganisms, indicating a greater antimicrobial potency. Conclusions Both aqueous plant extracts exhibited significant antibacterial and antifungal activity. Abrus precatorius showed superior antimicrobial efficacy compared to Achyranthes aspera; however, both extracts were less effective than the standard antimicrobial agents. These findings suggest the potential application of these herbal extracts in the development of oral healthcare products.
Prevalence surveys in U.S. hospitals in 2011 and 2015 showed that half of inpatients received antimicrobials on the survey day or day before. We repeated the survey in 2023 to assess changes in antimicrobial use (AU). Ten Emerging Infections Program (EIP) sites recruited up to 25 hospitals each, prioritizing prior participants. EIP staff reviewed medical records of randomly selected inpatients from the survey day morning census and documented AU on the survey day or day before. We compared AU and stewardship characteristics between 2023 and 2015 and used multivariable log-binomial regression to identify factors associated with AU in 2023. Antimicrobial stewardship programs were present in 215/218 hospitals in 2023 (98.6%) compared with 158/199 (79.4%) in 2015. Of 13 653 patients in 2023, 6785 (49.7%) received ≥1 antimicrobial on the survey day or day before. Among 151 hospitals participating in both surveys, overall AU prevalence was similar in 2015 and 2023 (49.2% vs 49.1%), with decreases in neonatal critical care (23.4% to 17.1%) and increases in mother-baby units (24.4% to 32.8%). Fluoroquinolone use declined (9.2% to 2.8%), while third- or fourth-generation cephalosporin use increased (12.3% to 18.6%). In 2023, higher AU was associated with patient factors (medical devices, inpatient location, obesity, 4-17 day hospital stays, and suburban residence) and hospital factors (Northeast and South regions, AU audits). One in two inpatients received an antimicrobial in 2023, similar to 2015. However, changes in AU by inpatient location and antimicrobial class suggest evolving prescribing practices and may inform targeted surveillance and stewardship efforts.
Introduction Ventilator-associated pneumonia (VAP) is a major cause of morbidity and mortality in ICU settings, with a greater impact when caused by multidrug-resistant Acinetobacter baumannii. This study examines the clinical profile, risk factors, antimicrobial resistance patterns, and prognostic indicators associated with VAP due to this organism in a tertiary care centre in South India. Methods This one-year cross-sectional study was conducted from January to December 2023 at KLE's Dr. Prabhakar Kore Hospital, Belagavi. A total of 68 patients with culture-confirmed VAP due to Acinetobacter baumannii were included. Clinical characteristics, comorbidities, risk factors, microbiological susceptibility, and prognostic scores, including the Glasgow Coma Scale (GCS), Acute Physiology and Chronic Health Evaluation II (APACHE II), quick Sequential Organ Failure Assessment (qSOFA), and Simplified Acute Physiology Score II (SAPS II), were analysed. Antimicrobial susceptibility testing was performed using institutional protocols, and resistance patterns were defined based on susceptibility across antimicrobial classes. Ethical approval was obtained from the institutional ethics committee. Results The mean age was 48 years, with 54 males (79.4%). Cerebrovascular accident and sepsis were the most common underlying diagnoses, observed in 22 (32.4%) and 13 (19.1%) patients, respectively. Mechanical ventilation was present in all patients. Central venous catheter use and glucocorticoid therapy were noted in 47 (69.1%) and 37 (54.4%) patients, respectively. Mortality was observed in 44 patients (64.7%). Non-survivors had higher prognostic scores. GCS ≤8, APACHE II >20, qSOFA >1, and SAPS II >43 were associated with higher mortality, with area under the curve (AUC) values of 0.928, 0.954, 0.937, and 0.971, respectively. Pan-drug resistance was observed in 49 (72.1%) isolates, while colistin sensitivity was seen in 11 (16.2%). Conclusion VAP due to Acinetobacter baumannii in this setting was associated with high mortality and a substantial burden of antimicrobial resistance. Prognostic scores, particularly SAPS II, showed strong associations with mortality; however, these findings should be interpreted in the context of the observational design. The results are hypothesis-generating and require validation in larger multicentre studies.
Companion animal shelters represent underexplored settings for One Health antimicrobial resistance (AMR) surveillance. This study investigated the recovery, antimicrobial resistance, and genomic features of Enterococcus spp. from shelter dogs and cats in the United Arab Emirates (UAE). Rectal swabs were collected from 230 shelter animals, including 129 dogs and 101 cats, across five shelters in four UAE emirates/cities. Enterococcus isolates were recovered using selective culture and identified by MALDI-TOF MS. Confirmed Enterococcus faecalis and Enterococcus faecium isolates underwent antimicrobial susceptibility testing using Vitek-2. Multidrug-resistant (MDR) and linezolid-resistant isolates were subjected to whole-genome sequencing (WGS) for multilocus sequence typing, resistome analysis, single-nucleotide polymorphism-based phylogeny, phenotype-genotype concordance assessment, and virulence-associated gene profiling. Enterococcus spp. were recovered from 122/230 animals (53.0%; 95% confidence interval: 46.6-59.4), with higher recovery in dogs (71.3% (92/129)) than cats (29.7% (30/101)). Overall, E. faecalis accounted for 63/122 isolates (51.6%) and E. faecium for 59/122 isolates (48.4%). Phenotypic resistance was most frequent for tetracycline (51.6%), erythromycin (30.3%), ciprofloxacin (27.2%), high-level streptomycin (20.5%), and high-level gentamicin (9.8%). All isolates were susceptible to ampicillin, vancomycin, teicoplanin, and tigecycline. MDR was detected in 25/122 isolates (20.5%) and was more frequent among E. faecalis than E. faecium. Linezolid resistance was detected in two isolates recovered from two dogs, one male and one female, housed in the same shelter. WGS of 25 MDR or linezolid-resistant isolates revealed diverse sequence types, including dominant E. faecalis ST16, shelter-associated SNP clusters, and multiple resistance determinants, including erm(B), tet(L), tet(M), aminoglycoside resistance genes, quinolone resistance-associated mutations, and plasmid-predicted optrA in three E. faecalis isolates. Virulence-associated genes were more prominent in E. faecalis, particularly the endocarditis- and biofilm-associated pilus genes involved in adhesion and biofilm formation, together with a putative exoenzyme-associated factor potentially contributing to host interaction and bacterial fitness. Shelter dogs and cats in the UAE carried E. faecalis and E. faecium with phenotypic AMR, MDR profiles, and diverse genomic resistance determinants. The detection of linezolid resistance and plasmid-predicted optrA supports inclusion of shelter companion animals in regional One Health AMR surveillance.
This systematic review aims to describe the impact of specific antimicrobial stewardship program (ASP) strategies on implementation and stewardship-related outcomes. Systematic literature review. We systematically searched multiple databases using search terms that focused on stewardship and implementation. An original search was completed on October 29, 2021, and then updated on February 26, 2025. Studies were eligible for inclusion if they were in English, reported an antimicrobial resource outcome, and using either a comparison group or a pre/post design as a minimum level of rigor. Data from articles were extracted to understand the context and design of the evaluation, the types of approaches used, and outcomes assessed. Out of 2035 studies that were identified, we included 250 full-text peer-reviewed manuscripts. Of the 250 studies included, 52% were conducted in the USA. The majority (80%) of studies were conducted in inpatient settings, particularly in adult academic hospitals (29%). Programs were often implemented hospital-wide or across multiple specialties, with a focus on emergency medicine and intensive care units. Education or learning (64% of studies) and handshake stewardship (56% of studies) were by far the most common ASP strategies used. Mortality (36% of studies) and drug choice (57% of studies) were the most tracked patient and resource outcomes, respectively. Our review highlights the variability in approaches as part of ASPs, indicating a need for a more systematic understanding of how different approaches are implemented and their subsequent impact on antimicrobial use.
Enterococci are common commensals of the human gut and important opportunistic pathogens, with Enterococcus faecium and Enterococcus faecalis being the most clinically prevalent species. A significant epidemiological shift has emerged with an increasing clinical burden of E. faecium. To compare genomic evolution of E. faecium and E. faecalis, we performed whole-genome sequencing on 93 E. faecium and 32 E. faecalis isolates causing bloodstream infections at a single hospital (2022-2024). Analysis of patient demographics revealed that E. faecium infections originated from fewer sources than E. faecalis, with a higher proportion deriving from intra-abdominal infections. Multilocus sequence typing identified ST78 and ST789 as the predominant sequence types for E. faecium, whereas ST16 and ST179 were most common for E. faecalis. E. faecium carried more antimicrobial resistance genes and putative virulence marker (PVM)-type virulence genes than E. faecalis, with vancomycin resistance predominantly mediated by vanHAX (33/93, 35.5%) and a single E. faecalis isolate also carrying vanHAX (1/32, 3.1%); the structurally incomplete vanHMX gene cluster was detected in 11 E. faecium isolates. Pan-genome analysis indicated a larger core genome in E. faecalis compared to E. faecium, consistent with greater plasmid replicon diversity in the latter. Intra-host comparisons showed that two E. faecalis pairs from the same patient were clonally related, with one isolate acquiring a vanHAX plasmid conferring vancomycin resistance. In contrast, E. faecium isolates exhibited marked genomic diversity even among clonally related pairs. These findings suggest that E. faecium possesses greater genomic plasticity and adaptive potential to the clinical environment.IMPORTANCEThis study provides a detailed comparison of clinical and genomic features between Enterococcus faecium and Enterococcus faecalis from the same hospital setting. We show that E. faecium isolates, mainly ST78/ST789, carry more antimicrobial resistance genes and a higher number of putative virulence marker (PVM) genes than E. faecalis, reflecting their hospital-adapted nature. E. faecium also exhibits a smaller core genome and greater diversity of plasmid replicon types, indicating higher genomic plasticity and capacity for horizontal gene transfer. By contrast, E. faecalis retains a larger core genome and a set of classical virulence factors, and its within-host isolates are clonally related. These distinct genomic profiles help to understand how the two species adapt to clinical environments and may inform more targeted infection control strategies and resistance surveillance.
Evaluate the combination of sophorolipids and copaiba essential oil in a multifunctional facial formulation aimed at the treatment of conditions such as acne and herpetic folliculitis. Sophorolipids produced by Starmerella bombicola reached 38.37 g/L, predominantly in the lactonic form. Their antimicrobial activity, alone and combined with copaiba oil, was evaluated against Cutibacterium acnes, Staphylococcus aureus, and Staphylococcus epidermidis. The combination reduced the minimum inhibitory concentration against C. acnes from 62.50 to 31.25 μg/mL, demonstrating an additive effect. Antiviral assays showed strong anti-HSV-1 activity, with 95.58% inhibition in the virucidal test and 63.99% in the antiviral assay. Three dermocosmetic formulations were developed, and the optimized formulation achieved 91.45% inhibition of C. acnes and 26.17% antioxidant activity, confirming its multifunctional potential. The application of a formulation combining sophorolipids and copaiba oil shows promising potential for the treatment of skin conditions, demonstrating significant antimicrobial activity against C. acnes as well as adequate physicochemical stability.
South American camelids (SACs) are gaining popularity in the leisure sector, leading to human contact. However, data on pathogenic, zoonotic, and antimicrobial-resistant (AMR) bacteria in SACs remain limited. This study investigated the occurrence of AMR and virulence determinants in Escherichia coli isolated from feces of healthy alpacas and llamas in Germany. Between April 2021 and February 2023, longitudinal sampling was conducted on up to 20 animals per farm from 10 farms across six German federal states, with four sampling rounds at 6-month intervals. One random E. coli isolate per sample was obtained using a non-selective approach and tested for susceptibility to 14 antibiotics by broth microdilution, following EUCAST guidelines. In parallel, selective screening was performed to detect colistin- and carbapenem-resistant strains as well as ESBL/AmpC β-lactamase producers. Whole-genome sequence data from non-selectively obtained isolates mainly from round A and selectively obtained isolates from all rounds were used to identify AMR determinants and virulence-associated markers. Overall, 706 non-selectively isolated E. coli showed low resistance rates: sulfamethoxazole (4.5%), trimethoprim (1.8%), tetracycline (1.6%), ampicillin (1.4%), enrofloxacin (0.4%), cefotaxime (0.4%), colistin (0.1%), amoxicillin/clavulanate (0.1%), and piperacillin/tazobactam (0.1%). Eleven isolates exhibited multidrug-non-wild-type (MD-non-WT) phenotypes to ≥3 antimicrobial classes. Selective screening identified 18 mcr-1 and 70 cefotaxime non-WT isolates, but no carbapenem non-WT isolates. Resistance genes included bla CTX-M-1/14/15/27/55 (n = 54), bla DHA-1 (n = 4), bla CMY-2 (n = 4) and ampC promoter mutations (C42T) (n = 2). All colistin-resistant isolates carried mcr-1.1 on an IncI2 plasmid and originated from a single farm. Multilocus VNTR analysis revealed high genetic diversity with farm-specific clustering and temporal shifts. Although overall AMR prevalence was low, localized presence of ESBL- and AmpC-β-lactamase-producing and colistin-resistant E. coli indicates that SACs may represent AMR sources. Virulence profiling revealed few pathogenic E. coli except Shiga toxin-producing E. coli. These included low-virulence stx subtypes (stx1c, stx2b, and stx2f) and the high-virulence subtype stx2d, associated with enterohemorrhagic E. coli (EHEC) causing hemorrhagic colitis and hemolytic uremic syndrome in humans. Notably, detection of an EHEC isolate belonging to the O63:H6/ST583 lineage, a serotype/sequence type previously associated with severe clinical outcomes, highlights a zoonotic risk associated with SACs.
This study evaluated guava leaf essential oil (GL-EO) and flowers and seeds of Oliveria decumbens essential oil (Od-EO) for their antimicrobial, antioxidant and sensory effects in ground beef. The essential oils were applied individually and in combination to ground beef samples (control, GL-EO, Od-EO, and GL-EO + Od-EO), which were packaged in sterile polyethylene zip-lock bags and stored at 4°C for 10 days. In vitro analyses revealed concentration-dependent antimicrobial activity against both Gram-positive and Gram-negative pathogens, with Od-EO showing superior efficacy attributed to its high content of thymol and carvacrol. Antioxidant assays demonstrated strong radical scavenging capacity for both oils, with Od-EO exhibiting 1.5-fold higher activity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays compared to GL-EO (p < 0.05). In ground beef applications, microbiological analyses (total mesophilic/psychrotrophic counts, coliforms and fungi) showed that both oils significantly (p < 0.05) inhibited microbial growth, with the GL-EO + Od-EO combination exhibiting notable preservative effects (approximately 2 log CFU/g reduction compared to controls). Chemical analyses revealed 45% lower thiobarbituric acid reactive substances (TBARS) values in treated samples, total volatile basic nitrogen (TVB-N) levels maintained at < 20 mg/100 g throughout and improved storage, pH stability (6.3-6.5 vs. 6.8 in controls) (p < 0.05). Sensory evaluation indicated that the combined treatment received the highest acceptability scores for color, odor, texture, and overall acceptability, without negative sensory impact. The GL-EO treatment also achieved high scores in preserving odor and color. These effects are associated with the oils' bioactive compounds (thymol, carvacrol, limonene, β-caryophyllene). These results suggest that these essential oils, particularly in combination, can serve as effective natural preservatives, extending shelf-life while maintaining quality. All treatments significantly extended shelf-life by 4 days compared to control (p < 0.05).
Medical biofilms are a significant problem in chronic diseases like diabetic ulcers that do not heal, infections of medical devices and CF. The extracellular polymeric matrix is a barrier to antibiotic penetration. In search of an alternative, approaches based on antimicrobial peptides (AMPs) and enzymes have been developed to tackle the multi-drug resistance. This review collates the existing literature on zoonotic and bacterial origin AMPs, along with the matrix-disrupting and quorum-quenching enzymes, highlighting those which have proven to be effective in vitro/in vivo against clinical isolates from patients. Enzymes (e.g. cellulase, alginate lyase, and dispersin B) can break down matrix components or block critical signaling molecules and can be seen to have strong synergy with antibiotics, whereas AMPs disrupt cell membranes and downregulate genes that encode biofilm-forming proteins. Our analysis reveals however, a key translational bottleneck: there were no clinical trials in human subjects identified despite strong preclinical evidence of activity. This review discusses these encouraging pre-clinical findings and identifies specific physiological and challenges that need to be overcome to take these alternative therapies to clinical practice.
暂无摘要（点击查看详情）
Antimicrobial resistance (AMR) has diminished the effectiveness of present antibiotics, posing a huge threat to global community health and economic stability. This study investigates the CRISPR-Cas framework's potential as a cutting-edge tactic to fight antimicrobial resistance. Current applications, limitations, and prospective future uses are analyzed. CRISPR antimicrobial strategies, which bring together the latest developments in gene-targeting strategies, engineered delivery platforms, and translational applications to fight multidrug-resistant pathogens. CRISPR technology is different from traditional antimicrobial treatments that target general antimicrobial resistance genes, instead allowing targets to be eliminated specifically by sequence, while retaining beneficial microbial communities, which has the potential to be a transformative precision antimicrobial treatment. Nevertheless, there is still a need for optimization of delivery systems, specificity of targets, biosafety, and regulations to ensure successful clinical translation, especially given their amazing advances. Recent research confirms that CRISPR-based mechanisms also affect different bacterial species, including Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species, playing a key function in averting the emergence of resistance genes in these bacteria. Changes to CRISPR loci affect how resistance genes are targeted in ESKAPE pathogens, and CRISPR-Cas9 successfully lowers resistance by focusing on genes like tetM and ermB. A promising application of CRISPR-Cas systems in combating antimicrobial resistance (AMR) is the precise targeting of plasmid-borne mcr-1 resistance genes and other mobile genetic elements that facilitate the dissemination of colistin resistance. But the efficiency of CRISPR-Cas is diminished in some bacterial strains due to variations in their CRISPR loci. Enhancing transformation approaches and minimizing off-target impacts are critical challenges to confirm the precision and safety of CRISPR-based mechanisms in therapeutic applications. Advances in these areas are likely to continue to enable the development of next-generation CRISPR therapeutics for the effective management of multidrug-resistant bacterial infections.
Milk production from cows in Tanzania may not have reached optimum levels due to several constraints, including diseases such as mastitis. A cross-sectional study was conducted in the Kilosa, Mvomero, Lushoto and Handeni districts to establish the prevalence of mastitis, milk bacteria contamination and antimicrobial resistance in lactating cows. A total of 78 cows were examined for mastitis using udder palpation and California Mastitis Tests. Subsequently, milk samples were collected for bacteriological culture and antimicrobial susceptibility tests using standard protocols. The prevalence of mastitis in cows was 75.6%, dominated by subclinical mastitis, which accounted for 62.8% (p = 0.02732). Dairy cows were more affected by mastitis (82.1%) than local breeds (72%). Up to 78% of mastitis milk samples had bacterial contamination. A total of 137 bacterial isolates detected were categorised as non-mastitis (27.0%), subclinical (56.2%) and clinical (16.8%). The seven bacterial species identified were Staphylococcus aureus (20.4%), Staphylococcus epidermidis (19.7%), Listeria monocytogenes (18.2%), Listeria innocua (17.5%), Listeria ivanovii (9.5%), Streptococcus agalactiae (7.2%) and Escherichia coli (7.3%). Most of the milk samples (78.5%) containing bacterial isolates exhibited mixed infections. Up to 56.9% of milk samples from Tanzania Short Horned Zebu (TSHZ) contained mixed bacterial species. Cows from the Kilosa District had more isolates (33.6%) than the rest. More than 70% of the bacterial isolates were resistant to tetracycline, nalidixic acid and amoxycillin. S. aureus, S. epidermidis, E. coli and L. monocytogenes showed the highest resistance rates against amoxycillin/clavulanic acid, ampicillin and amoxycillin. A high prevalence of mastitis implies losses to farmers due to poor production and threatens public health from milk-borne diseases. This calls for urgent intervention measures to control mastitis, combat antimicrobial resistance and safeguard public health.
Klebsiella pneumoniae is an emerging pathogen of global concern due to its capacity to acquire antimicrobial resistance and virulence determinants, yet its presence in the food environment remains unexplored. This study investigated the prevalence, antimicrobial resistance, virulence genes, biofilm formation, and genomic characteristics of K. pneumoniae isolated from a widely consumed street food in Bangladesh. A total of 90 fuchka and related samples from different sources were collected and analyzed using culture-based methods, PCR confirmation, matrix-assisted laser desorption ionization time-of-flight assay, and 16S rRNA sequencing. Antibiotic sensitivity was determined using the disk diffusion method, and resistance- and virulence-associated genes were detected by PCR. Biofilm formation was quantified using a 96-well microtiter plate assay, and genetic diversity was assessed by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) fingerprinting. Whole-genome sequencing (WGS) was performed on four representative isolates for in-depth genomic characterization. K. pneumoniae was recovered from 46.7% of samples. Among the isolates, 37.5% exhibited a multidrug-resistant (MDR) phenotype, with universal resistance to ampicillin. Virulence genes including wabG (90.5%) and uge (95.2%) were highly prevalent, whereas rmpA and bfp were absent. Capsular serotypes K3 and K5 were detected in 16.7% of isolates. The class 1 integron (int1) (83.3%) and tetA (56.7%) were the most frequently detected resistance determinants. Biofilm formation was observed in 31% of isolates and significantly associated with the MDR phenotype. WGS revealed clinically relevant sequence types (ST2262) phylogenomically related to human clinical strains. These findings indicate that fuchka may act as a reservoir for virulent and MDR K. pneumoniae, highlighting the urgent need for improved hygiene practices and integration of street food into the One Health antimicrobial surveillance framework. The presence of multidrug-resistant (MDR) Klebsiella pneumoniae in ready-to-eat street foods poses a significant public health concern, particularly in low- and middle-income countries where informal food vending is widespread. Fuchka is consumed daily by diverse population groups in Bangladesh, including children and young adults, making it a potential route for silent transmission of clinically important pathogens. The detection of MDR strains harboring virulence factors, integrons, and biofilm-forming ability suggests an elevated risk of persistence, spread, and limited treatment options in case of infection. This study highlights street food as an overlooked reservoir in the One Health framework, bridging community environments and clinical settings. Improved surveillance, vendor hygiene training, and enforcement of food safety regulations are crucial to reduce the risk of dissemination of these high-risk strains.
Campylobacter jejuni and Campylobacter coli are leading causes of foodborne illnesses, including human enteritis and diarrhoea, in many countries. The prevalence of antibiotic-resistant Campylobacter is increasing in both developing and developed countries, with fluoroquinolone-resistant Campylobacter recognised as a priority pathogen among antibiotic-resistant bacteria. Surveillance of Campylobacter antimicrobial resistance (AMR) is conducted worldwide because of its public health importance. In this study, we characterised the antimicrobial resistance patterns and genomic diversity of C. jejuni and C. coli strains isolated from food handlers in Japan. Surveillance was conducted on 106 Campylobacter isolates from food handlers between 2008 and 2023. Species identification by 16S rRNA sequencing, antimicrobial susceptibility testing, and whole-genome sequencing of selected isolates were performed to characterise phenotypic and genotypic features, compare AMR profiles, and assess phylogeny. Multilocus sequence typing (MLST) identified 36 sequence types (STs), including three novel STs and 10 clonal complexes (CCs). Among C. jejuni, CC21 (20.6%) was the most prevalent, followed by CC353 (2.8%). In C. coli, CC828 (4.7%) was the most prevalent. The AMR profiles and resistance determinants were as follows: quinolones (68.2%); mutations in the quinolone resistance-determining region (gyrA T86I); tetracyclines (40.2%); acquisition of tet(O) and macrolides (2.8%); and mutations in the 23S rRNA gene (A2075G). ST4526 (8.4%), reported only in Japan, was the most prevalent; however, it has not been detected since 2021, suggesting recent ST diversification. This study characterised the AMR profiles and genetic backgrounds of non-clinical human-derived Campylobacter strains isolated from food handlers.
Brucellosis is a zoonotic infection that may rarely involve the cardiovascular system, causing infective endocarditis. Diagnosis of Brucella-associated cardiac implantable electronic device (CIED) endocarditis is challenging because of its indolent course and frequently negative blood cultures. A 42-year-old shepherd with an implantable cardioverter-defibrillator had experienced fever, myalgia, arthralgia, and weight loss for approximately 18 months. During this period, investigations for malignancy and rheumatologic diseases were unrevealing. He was subsequently diagnosed with brucellosis at another institution based on a Brucella serum agglutination test positive at a titre of 1:1280, and antibiotic therapy was initiated. Three weeks later, he was referred to our centre because of generator pocket erosion and purulent drainage. Tissue cultures from the pocket and repeat blood cultures showed no growth. Transoesophageal echocardiography demonstrated a 14 × 8 mm mobile mass attached to the right ventricular lead, suspicious for vegetation. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) demonstrated increased metabolic uptake around the lead. According to the diagnostic criteria of the 2023 European Society of Cardiology Endocarditis Guidelines, Brucella CIED-related endocarditis was diagnosed. Antimicrobial therapy was revised, followed by complete percutaneous device extraction. The patient recovered without recurrence, and device re-implantation was not indicated. Brucella infection should be considered in patients from endemic regions or high-risk occupational groups presenting with culture-negative CIED infection. In such cases, serological testing combined with transoesophageal echocardiography and 18F-FDG PET/CT is essential for diagnosis. Complete device extraction with targeted antimicrobial therapy is crucial, and re-implantation should be individualized.
The multidrug-resistant pathogen Clostridioides difficile (C. difficile) presents a persistent clinical threat. While Multidrug and Toxic Compound Extrusion (MATE) transporters are recognized as xenobiotic efflux pumps, their pleiotropic roles in pathogen physiology, particularly in stress adaptation and virulence regulation, remain largely unexplored. Understanding how C. difficile adapts and thrives in the face of host defenses and antimicrobial pressures, potentially influencing gut microbiome dynamics, is crucial for combating C. difficile infection. We functionally characterized the MATE transporter gene CD20030 (mate) in C. difficile 630. A markerless deletion mutant (Δmate) and a complemented strain were constructed using a CRISPR-Cas9 system. Phenotypic assays determining antimicrobial susceptibility, oxidative stress tolerance, autolysis, and cytotoxicity were integrated with comparative proteomic profiling to assess the physiological changes. The Δmate mutant demonstrated broad-spectrum hypersensitivity to antibiotics and hydrogen peroxide, indicating the involvement of this transporter in intrinsic resistance and oxidative defense. The mutant exhibited reduced autolysis; however, toxin production (tcdA and tcdB) and cytotoxicity were significantly upregulated. In soft agar assays, the mutant showed expanded surface spreading. Proteomic data identified a >10,000-fold downregulation of flagellar structural proteins (FliC, FlgC) and a concurrent upregulation of the surface adhesin CwpV. This molecular evidence indicates a "swimming-to-sliding transition" driven by metabolic stress, rather than active swimming motility. These phenotypic and proteomic shifts present a resource reallocation strategy, where the bacterium sacrifices energy-consuming flagellar assembly to prioritize survival and virulence, potentially altering its interaction with the gut epithelial surface and resident microbiota. The MATE transporter (CD20030) operates as a pleiotropic regulatory hub and metabolic sentinel in C. difficile. Its absence induces metabolic reprogramming that orchestrates a motility-virulence trade-off, linking multidrug resistance directly to bacterial pathogenesis. These physiological adaptations likely dictate the pathogen's colonization and persistence strategies within the gut niche, potentially perturbing the host-microbiome equilibrium during infection.
Contact-dependent and diffusible proteinaceous polymorphic toxin systems (PTSs) mediate widespread bacterial competition. While bioinformatic analyses have identified diverse PTSs across bacterial phyla, experimental validation in gram-positive species remains limited. Here, we characterize a diffusible polymorphic toxin encoded by the Staphylococcus aureus S8-Ntox35 locus. We demonstrate that this system mediates inter-genus antagonism against Listeria monocytogenes via a bactericidal, heat-labile protein and that toxicity is enhanced following extracellular cleavage of the BetaH domain by the associated S8 peptidase. This processed toxin bears a peptide resembling a cationic antimicrobial peptide (CAMP) and facilitates intoxication of target cells by the Ntox35 RNase domain. Target cell resistance is impacted by known CAMP defense pathways, including DltABCD and MprF, and experimental evolution identified the ATP-binding cassette (ABC) transporter AnrAB as essential for intoxication. Unexpectedly, disruption of AnrAB abolished Ntox35 susceptibility, while simultaneously sensitizing cells to the proposed CAMP-like activity of the processed BetaH domain. These findings reveal a novel mechanism of inter-genus antagonism among Firmicutes (Bacillota) and establish a functional role for extracellular processing and ABC transporter-mediated susceptibility in PTS activity. Our work expands the known repertoire of diffusible toxins in gram-positive bacteria and sets the foundation for broader ecological and mechanistic investigation of the S8-associated polymorphic toxin system (S8-PTS). Polymorphic toxin systems (PTSs) are widely used by bacteria to inhibit competitors, but diffusible proteinaceous toxins have been largely characterized in gram-negative species. Here, we mechanistically characterize a diffusible PTS in Staphylococcus aureus that mediates inter-genus antagonism in the Firmicutes phylum. This system employs a secreted S8 peptidase to cleave a BetaH-toxin fusion, releasing a previously caged cationic amphipathic α-helix that facilitates membrane targeting and intoxication of susceptible cells. We further show that toxin activity requires the target cell ATP-binding cassette (ABC) transporter AnrAB, revealing a novel route of entry and an evolutionary tradeoff between toxin susceptibility and antimicrobial peptide resistance. Together, these findings uncover a new mode of bacterial competition and highlight a broadly distributed toxin system with ecological relevance across Firmicutes.
The emergence of drug-resistant bacteria has brought a grand challenge to the treatment of oral ulcers (OUs). Peroxidase (POD) enzymes catalyze the conversion of hydrogen peroxide (H2O2) into reactive oxygen species (ROS), offering a promising strategy for treating drug-resistant bacterial infections and oral wound therapy. Among them, two-dimensional conjugated metal-organic frameworks (2D-cMOFs) with high π-π conjugated structure and efficient electron transport capability serve as potent POD mimics, enhancing ROS generation for targeted antimicrobial applications. However, the reported single-metal-center 2D cMOFs possess the intrinsically weak adsorption interaction with H2O2, usually decreasing the conversion of H2O2 to ROS, exhibiting relatively low enzymatic activity and antibacterial performance. Herein, we reported a new class of Ni doped Cu 2D cMOFs, defined as CuNi-HHTP 2D-cMOFs, for constructing dual activity site to enhance the adsorption and activation of H2O2, which significantly facilitates the treatment of OUs. Mechanism investigation reveals the introduction of Ni atom upshifts the d-band center of CuNi-HHTP 2D-cMOFs from -2.563 to -2.084 eV, which enhances the adsorption and activation of H2O2, endowing its 5.0-fold enhancement in bactericidal efficiency. Besides, the as-made CuNi-HHTP 2D-cMOFs show improved antibacterial performance in vivo, which significantly promote OU healing, with macroscopic wound closure on the 7th day.