The aim of this work was to detect Escherichia coli isolates displaying resistance to oxyimino-cephalosporins, quinolones, and colistin in feces from livestock in Uruguay. During 2016-2019, fecal samples from 132 broiler and layer chicken flocks, 100 calves, and 50 pigs, were studied in Uruguay. Samples were cultured on MacConkey Agar plates supplemented with ciprofloxacin, ceftriaxone, or colistin. E. coli isolates were identified by mass spectrometry and antibiotic susceptibility testing was performed by disk diffusion agar method and colistin agar test. Antibiotic resistance genes were detected by polymerase chain reaction and sequencing. The most frequently detected resistance gene was qnrB19, recovered from 87 animals. Regarding plasmid-mediated quinolone resistance genes, qnrS1 was the second in prevalence (23 animals) followed by qnrE1, found in 6 chickens and two calves. Regarding resistance to oxyimino-cephalosporins, 8 different β-lactamase genes were detected: bla CTX−M−8 and bla CMY−2 were found in 23 and 19 animals, respectively; next, bla CTX−M−2 and bla SHV−12 in 7 animals each, followed by bla CTX−M−14 in 5, bla CTX−M−15 and bla SHV2a in 2, and bla CTX−M−55 in a single animal. Finally, the mcr-1 gene was detected only in 8 pigs from a single farm, and in a chicken. Isolates carrying bla CMY−2 and bla SHV−12 were also found in these animals, including two isolates featuring the bla CMY−2 /mcr-1 genotype. To the best of our knowledge, this is the first work in which the search for transferable resistance to highest priority critically important antibiotics for human health is carried out in chickens and pigs chains of production animals in Uruguay.

Antimicrobial resistance is a critical issue that is no longer restricted to hospital settings, but also represents a growing problem involving intensive animal production systems. In this study, we have performed a microbiological and molecular investigation of priority pathogens carrying transferable resistance genes to critical antimicrobials in one-day-old chickens imported from Brazil to Uruguay. Bacterial identification was performed by MALDI-TOF mass spectrometry and antibiotic susceptibility was determined by Sensititre. Antimicrobial resistance genes were sought by polymerase chain reaction and clonality was assessed by PFGE. Four multidrug-resistant (MDR) representative strains were sequenced by Illumina and/or Oxford Nanopore Technologies. Twenty-eight MDR isolates identified as Escherichia coli ( n = 14), Enterobacter cloacae ( n = 11) and Klebsiella pneumoniae ( n = 3). While resistance to oxyiminocephalosporins was due to bla CTX-M-2 , bla CTX-M-8 , bla CTX-M-15 , bla CTX-M-55 and bla CMY-2 , plasmid-mediated quinolone resistance was associated with qnrB19 , qnrE1 , and qnrB2 genes. Finally, resistance to aminoglycosides and fosfomycin was due to the presence of 16S rRNA methyltransferase rmtG and fosA -type genes, respectively. Short and long-read genome sequencing of E. cloacae ODC-Eclo3 strain revealed the presence of IncQ/ rmtG (pUR-EC3.1, 7400-pb), IncHI2A/ mcr-9.1 / bla CTX-M-2 [pUR-EC3.2, ST16 (pMLST), 408,436-bp] and IncN2/ qnrB19 / aacC3 / aph(3’’)-Ib (pUR-EC3.3) resistance plasmids. Strikingly, the bla CTX-M-2 gene was carried by a novel Tn 1696 -like composite transposon designated Tn 7337 . In summary, we report that imported one-day-old chicks can act as Trojan horses for the hidden spread of WHO critical priority MDR pathogens harboring mcr-9 , rmtG and extended-spectrum β-lactamase genes in poultry farms, which is a critical issue within a One Health perspective. Importance section Antimicrobial resistance is considered a significant problem for global health, including within the concept of "One Health", therefore, the food chain is a link that connects human and animal health directly. In this work, we searched for microorganisms resistant to antibiotics considered critical for human health in intestinal microbiota of one-day-old baby chicks imported to Uruguay from Brazil. We described antibiotic-resistant genes to antibiotics named as to watch or reserve for the WHO, such as rmtG or mcr9.1 , which confers resistance to all the aminoglycosides and colistin, respectively, among others genes, and their presence in new mobile genetic elements that favor its dissemination. The sustained entry of these microorganisms evades the sanitary measures implemented by the countries and production establishments to reduce the selection of resistant microorganisms. These silently imported resistant microorganisms could explain a considerable part of the antimicrobial resistance problems found in the production stages of the system.

No abstract

The objective of this study was to estimate the true prevalence of seropositive broiler chickens against avian pneumovirus at flock-level in Uruguay, using the Rogan-Gladen estimator in conjunction with Bayesian inference. A total of 181 pooled samples (consisting of 10 individual-chicken sera each) from the study area were examined with the enzyme-linked immunosorbent assay. All individual-chicken samples in the pools were also examined with the same assay. Forty-four pools were classified as test positive, because they included at least one individual-chicken classified as positive. The estimates for the deterministic (Rogan-Gladen approach) and stochastic (Bayesian approach) true prevalence were 30.9% [95% confidence interval (Cl): 26.8-35.0%] and 31.4% (95% Cl: 15.4-49.5%), respectively.

No abstract