Avaliação da resistência antimicrobiana e da virulência em cepas bacterianas isoladas de aves em estabelecimentos de corte e postura no estado do Rio de Janeiro

Abstract

The antimicrobials use in poultry industry is widelly spread for prophylatic and terapeutic purposes and as an additive. For the use as additive, small doses are administrated with the ration, leading to emergence of resistent bacterial strains. Brazilian Ministry of Agriculture, Livestook and Food Supply prohibits the use of Tetracyclines, β-lactams, Systemic Sulfona-mides and Colistin Sulfates as additives but allows their use for therapeutical purposes. There-fore, this study aims to verify the resistance levels of the antimicrobial classes of β-lactams, Polimyxins and Glycopeptides in Escherichia coli, Staphylococcus spp. Bordetella spp. and Enterococcus in samples from poultry farms of the Rio de Janeiro state. According to Phe-notipic and Proteomic analysis 88 strains of the genus Staphylococcus spp. were identified, 14% (12/88) presented resistance only to OXA, 10% (9/88) presented resistance to PEN and only 1% (1/88) to CFO, while 10% (9/88) were resistant to OXA and PEN and 2% (2/88) resistant to PEN, OXA and CFO. The universal mecA primer was able to detect the mecA gene in 7% (6/88) of strains of Staphylococcus spp., Followed by the mec SsciuriInt primer and blaZ with 6% (5/88) and 1% (1/88) respectively. None strain amplified the classical me-cA gene using the methodology described by Murakami et al. (1991). In this study, 107 strains of E. coli were obtained, where 71% (76/107) were resistant to SUT and 18% (19/107) were β-lactamase producers, being 58% (11/19) producing only ESBL, 10% (2/19) producing only AmpC whereas 26% (5/19) produced both ESBL and AmpC. The blaTEM gene was detected in 15% (16/107) of the E. coli strains and in 20% (4/19) of the β-lactamase produc-ers. 95% (102/107) of the E. coli strains were resistant to colistin, but mcr-1 gene being de-tected in only 58% (62/107), 31% of strains were considered APEC. 23 strains were identified as Bordetella spp. being 74% (17/23) B. hinzii and 26% (6/23) B. avium. In the disc diffusion test 94% (16/17) of the B. hinzii strains showed β-lactamase production whereas the B. avium strains were sensitive to the tested antimicrobials. Eleven strains of the genus Enterococcus spp. which were susceptible to vancomycin. These results highlight that, despite β-lactams and polimixins use forbiddence as additives, hight levels of those antimicrobials may still be found on field and that indiscriminated use of those drugs, even for therapeutical purposes, contributes to high circulation of resistance genes in bacterial population of farm animals, what may lead to future public health problems.