Production of extended-spectrum beta-lactamases in Escherichia coli isolated from poultry in Rio de Janeiro, Brazil.

The overuse of antimicrobials in poultry has led to the development and dissemination of multidrug-resistant bacteria in the poultry industry. One of the most effective mechanisms of resistance found in Escherichia coli is the production of extended-spectrum ß-lactamases (ESBL); there are several ESBLs, including the TEM, SHV, and CTX-M families. This resistance mechanism and the risks associated with transmitting these resistant microorganisms between animals, the environment, and humans can occur through direct contact and consumption of infected animals. This study aimed to determine the prevalence of E. coli in samples isolated from three broiler farms in Rio de Janeiro, Brazil, and screen the isolates for ESBL genes. The findings of this study demonstrated the presence of ESBL-producing E. coli in all farms studied. The findings of this study highlight the urgency for a program to monitor the poultry industry value chains at the regional level to control the spread of antimicrobial resistance. Therefore, we recommend that the enzyme subtypes produced by bacterial isolates should be determined to effectively characterize the distribution of genes related to antimicrobial resistance.

O uso excessivo de antimicrobianos em frangos de corte tem contribuído para o desenvolvimento e disseminação de bactérias multirresistentes, e um dos mais relevantes mecanismos de resistência encontrados em Escherichia coli é a produção de enzimas denominadas ß-lactamases de espectro estendido (ESBL). CTX-M, SHV e TEM são as ß-lactamases mais comumente encontradas nesta espécie e as ESBL mais prevalentes globalmente. Esse mecanismo de resistência e o risco associado à transmissão desses microrganismos resistentes entre animais, meio ambiente e seres humanos se devem principalmente ao contato direto e ao consumo de origem animal. Este trabalho buscou elucidar a prevalência de E. coli em amostras de três granjas de frangos de corte localizadas no Rio de Janeiro, Brasil, e caracterizá-las de acordo com seu genótipo. O estudo demonstrou uma presença consistente de E. coli produtora de ESBL com presença abundante do gene bla SHV nos isolados de todas as fazendas estudadas. Deste modo, este estudo teve como objetivo contribuir com dados epidemiológicos relativos à distribuição de genes relacionados às ß-lactamases na produção animal, conscientizando sobre a transmissão desses microrganismos resistentes entre animais, meio ambiente e seres humanos contribuindo com dados epidemiológicos e de sua importância em uma perspectiva de saúde única.

mcr-1 Identified in Fecal Escherichia coli and Avian Pathogenic E. coli (APEC) From Brazil.

Colisitin-associated resistance in bacteria of food producing animals has gained significant attention with the mcr gene being linked with resistance. Recently, newer variants of mcr have emerged with more than nine variants currently recognized. Reports of mcr associated resistance in Escherichia coli of poultry appear to be relatively limited, but its prevalence requires assessment since poultry is one of the most important and cheapest sources of the world's protein and the emergence of resistance could limit our ability to treat disease outbreaks. Here, 107 E. coli isolates from production poultry were screened for the presence of mcr 1-9. The isolates were collected between April 2015 and June 2016 from broiler chickens and free-range layer hens in Rio de Janeiro, Brazil. All isolates were recovered from the trachea and cloaca of healthy birds and an additional two isolates were recovered from sick birds diagnosed with colibacillosis. All isolates were screened for the presence of mcr-1 to 9 using PCR and Sanger sequencing for confirmation of positive genes. Additionally, pulse field gel electrophoresis (PFGE) analysis, avian fecal E. coli (APEC) virulence associated gene screening, plasmid replicon typing and antimicrobial resistance phenotype and resistance gene screening, were also carried out to further characterize these isolates. The mcr-1 gene was detected in 62 (57.9%) isolates (61 healthy and 1 APEC) and the mcr-5 gene was detected in 3 (2.8%) isolates; mcr-2, mcr-3, mcr-4, mcr-6, mcr-7, mcr-8, and mcr-9 were not detected in any isolate. In addition, mcr 1 and 5 positive isolates were phenotypically resistant to colistin using the agar dilution assay (> 8ug/ml). PFGE analysis found that most of the isolates screened had unique fingerprints suggesting that the emergence of colistin resistance was not the result of clonal dissemination. Plasmid replicon types IncI2, FIB, and B/O were found in 38, 36, and 34% of the mcr positive isolates and were the most prevalent replicon types detected; tetA and tetB (32 and 26%, respectively) were the most prevalent antimicrobial resistance genes detected and iutA, was the most prevalent APEC virulence associated gene, detected in 50% of the isolates. Approximately 32% of the isolates examined could be classified as APEC-like, based on the presence of 3 or more genes of APEC virulence associated path panel (iroN, ompT, hlyF, iss, iutA). This study has identified a high prevalence of mcr-1 in poultry isolates in Brazil, suggesting that animal husbandry practices could result in a potential source of resistance to the human food chain in countries where application of colistin in animal health is practiced. Emergence of the mcr gene and associated colisitin resistance in production poultry warrants continued monitoring from the animal health and human health perspective.

Letter to the Editor: Escherichia fergusonii Harboring IncHI2 Plasmid Containing mcr-1 Gene-A Novel Reservoir for Colistin Resistance in Brazil.

Emergence of colistin-resistant bacteria harboring mobile colistin resistance genes (mcr genes) pose a threat for food-producing animals and humans. In this article, we aim to highlight the emergence of Escherichia fergusonii as an important new reservoir to mcr-1-harboring plasmid in poultry production. Three strains closely related were isolated from cloacal swabs. Their genome contains four plasmids, including a 182,869 bp IncHI2 plasmid harboring the colistin resistance gene mcr-1. These results will contribute to our understanding of plasmid-mediated mcr-1 gene presence and transmission in E. fergusonii.

Characterization of quinolone resistance in Salmonella spp. isolates from food products and human samples in Brazil.

Non-typhoidal salmonellosis is an important zoonotic disease caused by Salmonella enterica. The aim of this study was to investigate the prevalence of plasmid-mediated quinolone resistance in Salmonella spp. and its association with fluoroquinolone susceptibility in Brazil. A total of 129 NTS isolates (samples from human origin, food from animal origin, environmental, and animal) grouped as from animal (n=62) and human (n=67) food were evaluated between 2009 and 2013. These isolates were investigated through serotyping, antimicrobial susceptibility testing, and the presence of plasmid-mediated quinolone resistance (PMQR) genes (qnr, aac(6')-Ib) and associated integron genes (integrase, and conserved integron region). Resistance to quinolones and/or fluoroquinolones, from first to third generations, was observed. Fifteen isolates were positive for the presence of qnr genes (8 qnrS, 6 qnrB, and 1 qnrD) and twenty three of aac(6')-Ib. The conserved integron region was detected in 67 isolates as variable regions, from ±600 to >1000pb. The spread of NTS involving PMQR carriers is of serious concern and should be carefully monitored.

Impairments of mecA gene detection in bovine Staphylococcus spp.

Staphylococcus aureus antimicrobial resistance, especially to beta-lactams, favors treatment failures and its persistence in herd environment. This work aimed to develop a more specific primer for mecA gene detection based on the comparison of the conserved regions from distinct host origins and also investigated the presence of homologue mecA(LGA251) in bovine strains. A total of 43 Staphylococcus spp. were included in this study, comprising 38 bovine S. aureus, two human and three equine coagulase-negative staphylococci (CNS). Phenotypical methicillin-resistance detection was performed through oxacillin agar-screening and cefoxitin disk-diffusion test. None isolate tested positive for mecA(LGA251) gene. For mecA gene PCR, new primers were designed based on the sequences of human S. aureus (HE681097) and bovine S. sciuri (AY820253) mecA. The new primers based on the S. aureus mecA sequence amplified fragments of human and equine CNS and the ones based on S. sciuri mecA sequence only yielded fragments for S. aureus bovine strains. Multiples alignments of mecA gene sequences from bovine, human and equine revealed punctual but significant differences in bovine strains that can lead to the mecA gene detection impairment. The observed divergences of mecA gene sequences are not a matter of animal or human origin, it is a specificity of bovine samples.