Search Results (24)

Background/Objectives: Antimicrobial resistance (AMR) can be influenced by the interconnection of human, animal and environmental compartments, making wildlife-based surveillance an important component of One Health surveillance. The red fox (Vulpes vulpes), due to its synanthropic behaviour and wide distribution, can be a valuable indicator of environmental AMR. Mobile colistin resistance (mcr) genes, which encode resistance to a highest-priority critically important antimicrobial (HPCIA), have never been identified in free-ranging foxes. Case presentation: A red fox faecal strain isolated using selective media was PCR-screened for major AMR genes, underwent antimicrobial susceptibility testing and whole-genome sequencing (WGS). This led to the identification of the first mcr-1-positive Escherichia coli from a wild red fox. The fox inhabited an area with a small human population but one of the highest cattle densities in Italy and high antimicrobial use (AMU), as established by comparing local livestock density and AMU with surrounding areas. Despite being borderline phenotypically susceptible to colistin, the isolate displayed resistance to other HPCIAs and antimicrobial classes commonly used in livestock. WGS revealed that mcr-1 was chromosomally integrated. Discussion: The study area showed near-zero colistin use in livestock alongside high overall AMU, suggesting that the mcr-1-positive isolate may have evolved through co-selection rather than direct colistin pressure. mcr-1 can persist and circulate in the environment, even where colistin use is minimal, and foxes may represent effective sentinels for tracking such events. Our results emphasise the importance of including wildlife in One Health surveillance frameworks to monitor AMR at the human–animal–environment interface. Full article

The occurrence of Escherichia coli resistant to high-priority critically important antimicrobials (HPCIA) in the food chain is a growing concern for food safety and public health. This study aimed to evaluate whether HPCIA-resistant E. coli isolated from pork and chicken meat at retail markets in La Plata, Buenos Aires, Argentina, exhibit source-associated genomic differentiation through whole-genome sequencing. The isolates displayed a polyclonal population structure, encompassing multiple phylogenetic groups and sequence types. Virulence gene profiles were highly diverse, with chicken-derived isolates harbouring a substantially higher number of virulence genes than pork isolates. Notably, one pork isolate carried a complete set of virulence genes characteristic of diarrheagenic E. coli. Single Nucleotide Polymorphism-based phylogenetic analysis revealed several closely related subclusters, including strains recovered from both pork and chicken meat from the same retail markets, suggesting recent clonal sharing or cross-contamination at the point of sale. These findings highlight the circulation of genetically diverse HPCIA-resistant E. coli in retail meat, underscoring the potential public health risk and the importance of monitoring resistance and virulence determinants throughout the food production chain. Full article

Background/Objectives: Antimicrobial resistance (AMR) is one of the greatest health threats affecting humans, animals and the environment. Antimicrobial use (AMU) in the livestock sector contributes to the development and spread of AMR, highlighting the need to understand the current situation, to target knowledge gaps and non-prudent practices with tailored interventions, and improve antimicrobial stewardship. This is especially important in low- and middle-income countries (LMICs), where data on AMU and AMR are currently limited. This study assessed knowledge, attitudes and practices (KAP) among farmers, veterinarians, veterinary pharmacy personnel and feed mill personnel related to AMU (particularly considering the use of antibiotics) and AMR in seven former Soviet countries, Armenia, Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan, Tajikistan and Ukraine. Methods: Face-to-face interviews were conducted between 2020 and 2025 with 3012 participants, with results analyzed using an aggregated regional approach. Results: The interviews revealed common regional knowledge gaps and practices among livestock sector stakeholders related to antimicrobials, AMR, antimicrobial residues, and prudent AMU. Non-prudent practices, such as the purchase of antimicrobials without a prescription, the use of antimicrobials as growth promoters, the inappropriate disposal of antimicrobials, and the frequent use of highest priority critically important antimicrobials (HPCIAs) were reported. Another factor that may hinder prudent AMU was the limited access of veterinarians to diagnostic laboratories. Conclusions: Despite significant global efforts to tackle AMR, there is an ongoing need to address knowledge gaps and non-prudent practices of livestock sector stakeholders in former Soviet countries. The findings highlight the importance of antimicrobial stewardship interventions that address system-level drivers of improper AMU beyond stakeholder trainings. Full article

Background: Antimicrobial resistance (AMR) is a growing global health concern, driven in part by antibiotic use in animal production systems. Despite its relevance, the microbiome and resistome of small ruminant farm environments remain largely underexplored. Methods: In this study, shotgun metagenomics was applied to environmental samples from 46 sheep, goat and mixed-species farms across 14 municipalities in central Portugal. Results: Microbial profiling revealed a well-preserved microbiome with Pseudomonadota, Actinomycetota, Bacteroidota and Bacillota (syn. Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes respectively) as the most dominant phylum across different farm types. Regarding AMR, a total of 706 unique antimicrobial resistance genes (ARGs), covering 15 antibiotic classes, were detected. Tetracycline, aminoglycoside and macrolide resistance genes dominated across all samples, forming a conserved core resistome. While overall resistome profiles were broadly similar among farm types, significant differences were observed in specific ARG classes, such as pleuromutilin and fosfomycin. Conclusions: These findings highlight small ruminant farm environments as potential reservoirs of clinically relevant ARGs, including WHO highest priority critically important antimicrobial (HPCIA) resistance genes for macrolides (mph(c), erm(f), erm(b)) and fluoroquinolones (qnrD1), as well as critically important antimicrobial (CIA) resistance genes for glycopeptides (vanR-SC, vanR-O) and aminoglycosides (str, aadA), supporting the need to incorporate these environments into surveillance strategies. Full article

Enterotoxigenic Escherichia coli (ETEC)-induced neonatal calf diarrhea (NCD) causes significant economic losses to the cattle industry; therefore, understanding its antibiotic resistance is crucial for developing targeted prevention and treatment strategies. However, reports on antibiotic resistance in bovine ETEC are currently limited. This study conducted whole-genome sequencing (WGS) and antimicrobial susceptibility testing on ETEC F5- and F5-F41-positive strains isolated from neonatal calf diarrhea samples in Inner Mongolia, China. The results showed that both ETEC F5- and ETEC F5-F41-positive strains are multidrug-resistant, containing ceftriaxone (CRO), ceftazidime (CAZ)) and ciprofloxacin (CIP), which are listed as the highest priority critically important antimicrobial (HP-CIAs) by the World Health Organization (WHO). Combined analysis using the Comprehensive Antibiotic Resistance Database (CARD) and ResFinder 4.1 predictive analysis revealed that the chromosomes and plasmids of the 2 ETEC-positive strains contained 11 classes of antibiotic resistance genes, with the top 3 categories in terms of the number of resistance genes being aminoglycosides, β-lactamases, and chloramphenicols. In addition, various bacterial efflux pumps, including RND, MFS, SMR, and the ABC efflux pump family, were detected. A total of 74 antimicrobial resistance genes were identified in the 2 strains, belonging to 5 categories of drug resistance mechanisms; the antimicrobial resistance phenotype was consistent with the genotype. This study provides a reference for the prevention and treatment of diarrhea caused by ETEC. Full article

High-risk clones represent a major concern, as they are very efficient vehicles for mobile genetic elements carrying antimicrobial resistance genes and therefore promote their spread, especially if they confer resistance to cefotaxime, ciprofloxacin, and fosfomycin, included within the highest-priority, critically important antimicrobial agents (HPCIA). Between February 2022 and April 2024, 138 pork samples were obtained from 46 butcher shops in La Plata, Buenos Aires, Argentina. A total of 102 HPCIA-resistant E. coli were isolated. Eighty-five HPCIA-resistant E. coli were selected for whole-genome sequencing. Of these, 27 belonged to 9 clones described as high risk: ST101 (n = 5), ST10 (n = 4), ST48 (n = 4), ST744 (n = 4), ST23 (n = 3), ST58 (n = 2), ST88 (n = 2), ST117 (n = 2), and ST410 (n = 1). Twelve of them were third-generation cephalosporin-resistant. Resistance was mediated by bla_CTX-M-55 (n = 7), bla_CTX-M-14 (n = 4), bla_CTX-M-8 (n = 1), and bla_CMY-2 (n = 1). This study highlights the importance of food products and the food production chain as reservoirs of high-risk clones and resistance genes of epidemiological relevance to public health. Full article

Antimicrobial resistance (AMR) is a growing global health threat, with wild birds increasingly recognized as potential reservoirs of resistant pathogens and as sentinels of environmental AMR. This study investigated the occurrence and AMR profiles of Gram-negative bacteria isolated from wild birds that died at the Wildlife Rescue Center in Vanzago, Lombardy, in 2024. Cloacal swabs were collected from 112 birds representing various ecological categories. A total of 157 Gram-negative bacteria were isolated and identified, including clinically relevant genera and species, such as Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Salmonella spp., Pseudomonas aeruginosa, and Acinetobacter baumannii. Antimicrobial susceptibility testing revealed resistance to first-line and critically important antimicrobials, including those exclusively authorized for human use. Notably, a phenotype compatible with Extended-Spectrum Beta-Lactamase (ESBL) production was detected in four out of ten (40%) K. pneumoniae isolates. In addition, 20 out of the 157 (12.7%) isolated bacteria phenotypically exhibited a resistance profile indicative of AmpC beta-lactamase (AmpC) production, including Enterobacter spp. and P. aeruginosa. Resistance patterns were particularly interesting in birds with carnivorous, scavenging, or migratory-associated behaviors. These findings highlight the role of wild birds in the ecology and dissemination of antimicrobial-resistant bacteria (ARB) and highlight the need for wildlife-based AMR monitoring programs as part of a One Health approach. Full article

Background: Short food supply chains are commonly perceived as more sustainable and safer alternatives to conventional production systems, often linked to organic, free-range livestock practices. Materials and methods: This study investigates, for the first time, the distribution of antimicrobial resistance genes (ARGs) and characterizes the microbial communities’ composition, using 16S rRNA sequencing and real-time PCR, respectively. Eleven fecal, 76 slaughterhouse surface, 11 cecal, and 11 carcass samples, from 11 poultry farms belonging to the same short food chain, were analyzed in the study. Results: While cleaning and disinfection procedures appeared to reduce the bacterial load on slaughterhouse surfaces, diverse and potentially resistant bacteria, including genera such as Staphylococcus and Streptococcus, persisted both before and after slaughter. ARGs conferring resistance to high-priority critically important antimicrobials (HPCIAs), such as fluoroquinolones and third-generation cephalosporins, were frequently detected on carcasses, with qnrS (76.15%, 95%CI 68.02-84.28%) and bla_CMY2 (57.8%, 95%CI 48.38-67.22%) being the most prevalent. The slaughtering process emerged as a critical step for ARG dissemination via intestinal bacteria, such as genus Lactobacillus. Additionally, the detection of mcr genes and bla_NDM on carcasses but not in the bird gut samples suggests possible anthropogenic contamination. Discussion: These findings highlight that the evisceration process, slaughterhouse environment, and personnel are all contributing factors in ARG spread and underscore the need for enhanced hygiene protocols and reduced gut ARG carriage in domestic birds to mitigate the risk for the consumer. Full article

Background: Antimicrobials are crucial for animal health and food security. However, their overuse in animals can lead to the emergence of resistant microorganisms. Antimicrobial resistance (AMR) poses a global public health threat that impacts both animal and human health. The objective of this study was to estimate the antimicrobial consumption (AMC) of veterinary antimicrobials at the national level using import data from January to December 2021, available from the Uganda National Drug Authority (NDA). Methods: The World Organization for Animal Health (WOAH) methodology was applied using the Anatomical Therapeutic Chemical classification codes for veterinary medicines. Results: Approximately 88,387.37 kg (88.39 tonnes) of veterinary antimicrobials were consumed in 2021. Parenteral veterinary antimicrobials accounted for 63.8% (56,375.65 kg) and oral veterinary antibacterials accounted for 36.2% (32,011.71 kg). Tetracyclines were the single most consumed veterinary antimicrobial class, accounting for 62.7% of total consumption. Oxytetracycline was the most consumed antibacterial (58.4%), followed by sulphadiazine + trimethoprim (11.1%), penicillin g/dihydrostreptomycin (7.4%), penicillin G procaine + dihydrostreptomycin (6.8%), and tetracycline (3.5%), respectively. Out of all imported veterinary antimicrobials, 76% belonged to the World Health Organization (WHO)’s Highly Important Antimicrobials (HIA) category, 16% to the Critically Important (CIA), and 9% to the Highest Priority Critically Important (HPCIA) categories. Imported colistin accounted for 0.1% of total veterinary consumption. Conclusions: This study contributes to understanding antimicrobial consumption in Uganda’s livestock sector and, for the NDA, leaves in place a system for routine surveillance at a national level. We recommend strict regulatory oversight on the importation and use of colistin and macrolides to address AMR. Full article

Background/Objectives: While antibiotic usage in farm animals has been systematically monitored and reduced in many countries, including Germany, data on companion animals such as dogs and cats remain scarce. To address this gap, a study was conducted in Germany to analyze patterns of antibiotic use in dogs and cats. Methods: Antibiotic usage data were obtained from debevet, a cloud-based veterinary practice management software based in Berlin, Germany. Practices with fewer than 100 patients were excluded, and data from 2018 to 2022 were analyzed. Results: The analysis included 477,310 consultations of 78,381 dogs and 241,532 consultations of 55,729 cats across 133 veterinary practices. Antibiotics were used in 12.9% of dog consultations and 22.5% of cat consultations, with substantial variation across practices. Aminopenicillins, particularly amoxicillin, were the most commonly used antibiotics, while the highest-priority critically important antibiotics (HPCIAs) accounted for 12.4% of treatments. Follow-up treatments led to changes in antibiotic substances in 9.3% of cases, often within the first two days. Indications varied by species, with respiratory issues more frequent in cats and orthopedic problems in dogs. Body weight and breed characteristics influenced the likelihood of antibiotic treatment, with short-nosed breeds showing higher odds. Conclusions: The routine data analysis provided valuable insights into antibiotic use in dogs and cats, enabling tracking trends across species and indications over time. While some specific information was missing, the invoicing data’s completeness, the cost-effectiveness of their use, and their unbiased nature make them a robust tool for monitoring and informing legislative changes. Full article

Background/Objectives: Antimicrobial resistance (AMR) is a global public health threat, with antimicrobial use (AMU) in livestock recognized as a significant driver. This study examines farm-level AMU and AMR as well as the relationship between AMU and AMR on broiler farms in Indonesia. Methods: Data were collected from 19 farms in West Java between 2019 and 2021 to examine AMU in depth across four to five successive production cycles. The correlation between AMU and AMR in commensal Escherichia coli (E. coli) was investigated. AMU was recorded as treatment days per 30-day production cycle, and antimicrobial susceptibility was assessed using epidemiological cut-off (ECOFF) values to differentiate wildtype (WT) and non-wildtype (NWT) E. coli. Results: The average AMU was 12 treatment days per 30-day production cycle, with a wide range of 4 to 22 days. On average, E. coli isolates from each farm exhibited NWT phenotypes, reflecting AMR levels, for 6 out of 14 antimicrobials tested. This included notable levels for the highest priority critically important antimicrobials (HPCIAs) ciprofloxacin (93%) and nalidixic acid (64%). A significant correlation (Spearman ρ = 0.67, p < 0.05) was observed between the total farm-level AMU and the number of antimicrobials for which NWT E. coli isolates were found. However, no significant correlation was found between AMU and AMR for the five most frequently used antimicrobials, likely due to a high baseline prevalence of NWT E. coli isolates and relatively few independent observations. Conclusions: These findings highlight the urgent need to reduce AMU in general, specifically the use of (HP)CIAs, to mitigate AMR on Indonesian broiler farms. Full article

Companion animal ownership has evolved to new exotic animals, including small mammals, posing a new public health challenge, especially due to the ability of some of these new species to harbour zoonotic bacteria, such as Salmonella, and spread their antimicrobial resistances (AMR) to other bacteria through the environment they share. Therefore, the objective of the present pilot study was to evaluate the current epidemiological AMR situation in commensal Escherichia coli and Salmonella spp., in non-traditional companion animal small mammals in the Valencia region. For this purpose, 72 rectal swabs of nine different species of small mammals were taken to assess the antimicrobial susceptibility against 28 antibiotics. A total of one Salmonella enterica serovar Telelkebir 13,23:d:e,n,z₁₅ and twenty commensal E. coli strains were isolated. For E. coli strains, a high prevalence of AMR (85%) and MDR (82.6%) was observed, although neither of them had access outside the household. The highest AMR were observed in quinolones, one of the highest priority critically important antimicrobials (HPCIAs) in human medicine. However, no AMR were found for Salmonella. In conclusion, the results showed that small mammals’ commensal E. coli poses a public health risk due to the high AMR found, and the ability of this bacterium to transmit its resistance genes to other bacteria. For this reason, this pilot study highlighted the need to establish programmes to control AMR trends in the growing population of new companion animals, as they could disseminate AMR to humans and animals through their shared environment. Full article

Between June and September 2023, a total of 80 meat samples from pork and chicken meat were collected from 16 retail markets in La Plata, Argentina. Eighty-four highest priority critically important antimicrobial-resistant Escherichia coli and two Salmonella spp. were isolated. Resistance to ciprofloxacin and cefotaxime was observed in 65 and 49 E. coli isolates, respectively. Seventy-five E. coli isolates were multidrug resistant. Fourteen E. coli isolates from chicken meat showed resistance to three of the HPCIA. Resistance to third-generation cephalosporin was associated with bla_CTX-M. It is 15 times more likely to find HPCIA-resistant E. coli in chicken meat than in pork. Full article

Mobile colistin resistance (mcr) genes (mcr-1 to mcr-10) are plasmid-encoded genes that threaten the clinical utility of colistin (COL), one of the highest-priority critically important antibiotics (HP-CIAs) used to treat infections caused by multidrug-resistant and extensively drug-resistant bacteria in humans and animals. For more than six decades, COL has been used largely unregulated in the poultry sector in low- and middle-income countries (LMICs), and this has led to the development/spread of mcr gene-containing bacteria (MGCB). The prevalence rates of mcr-positive organisms from the poultry sector in LMICs between January 1970 and May 2023 range between 0.51% and 58.8%. Through horizontal gene transfer, conjugative plasmids possessing insertion sequences (ISs) (especially ISApl1), transposons (predominantly Tn6330), and integrons have enhanced the spread of mcr-1, mcr-2, mcr-3, mcr-4, mcr-5, mcr-7, mcr-8, mcr-9, and mcr-10 in the poultry sector in LMICs. These genes are harboured by Escherichia, Klebsiella, Proteus, Salmonella, Cronobacter, Citrobacter, Enterobacter, Shigella, Providencia, Aeromonas, Raoultella, Pseudomonas, and Acinetobacter species, belonging to diverse clones. The mcr-1, mcr-3, and mcr-10 genes have also been integrated into the chromosomes of these bacteria and are mobilizable by ISs and integrative conjugative elements. These bacteria often coexpress mcr with virulence genes and other genes conferring resistance to HP-CIAs, such as extended-spectrum cephalosporins, carbapenems, fosfomycin, fluoroquinolone, and tigecycline. The transmission routes and dynamics of MGCB from the poultry sector in LMICs within the One Health triad include contact with poultry birds, feed/drinking water, manure, poultry farmers and their farm workwear, farming equipment, the consumption and sale of contaminated poultry meat/egg and associated products, etc. The use of pre/probiotics and other non-antimicrobial alternatives in the raising of birds, the judicious use of non-critically important antibiotics for therapy, the banning of nontherapeutic COL use, improved vaccination, biosecurity, hand hygiene and sanitization, the development of rapid diagnostic test kits, and the intensified surveillance of mcr genes, among others, could effectively control the spread of MGCB from the poultry sector in LMICs. Full article

Antimicrobial usage in both human and veterinary medicine is considered one of the main drivers of antimicrobial resistance; its reduction poses a serious challenge. To analyse the associations between usage and resistance, data from monitoring systems and classification of all antimicrobial substances are crucial. In this analysis, we investigated longitudinal data collected between 2013 and 2020 within the Veterinary Consumption of Antibiotics project from pig farms in Germany, including all antimicrobial classes, but focusing on critically important antimicrobials: third- and fourth-generation cephalosporins, fluoroquinolones, macrolides, and polymyxins. Analysing the treatment frequency, we found that a reduction in antimicrobial use in all types of pig production has occurred over time, accompanied by a rising percentage of farms without any usage. The lists of the World Health Organisation, World Organisation for Animal Health, and European Medicine Agency classify different antimicrobial substances as critically important. The vast differences between the respective weighted treatment frequencies allocated to the antimicrobials of main interest reflect the huge impact of the three categorisation systems. We concluded that, with the aim of creating national treatment guidelines supporting veterinarians to make treatment decisions, the list of the European Medicine Agency is the most suitable. Full article