Resistência antimicrobiana em Enterobacterales isoladas de galinhas poedeiras e caipiras em condições semiáridas brasileiras.

Abstract

The poultry production of meat and eggs in Brazil is growing and generates employment and income not only for large producers but also for small rural families, who use these products for subsistence. To maintain the health of these animals and increase productivity, the use of antimicrobials in an empirical and uncontrolled way has increased, and as a consequence bacteria have become reservoirs of antimicrobial resistance genes, characterizing a global public health problem. Thus, the objectives of this study were to isolate and identify microorganisms from the cloaca of laying hens and free-range chickens in the Brazilian semiarid region, characterize the resistance profile and identify antimicrobial resistance genes of the isolates. A total of 330 cloacal swabs from laying hens and free-range chickens raised in Brazilian semiarid conditions (165 swabs from laying hens and 165 swabs from free-range chickens) were collected from September 2019 to September 2020. The samples were subjected to bacterial culture with subsequent biochemical identification, and in the isolates were checked for susceptibility to antimicrobials, phenotypic test for ESBL production and identification of resistance genes, , blaCTX-M and blaCMY. A total of 152 Enterobacteriales were isolated from laying hens and 198 from free-range hens. The microorganisms most frequently isolated from laying hens were E. coli (73.7%), Klebsiella spp. (13.2%), Proteus mirabilis (5.3%) and Salmonella spp. (3.3%), and E. coli (67.5%), Klebsiella spp. (12,5%), Edwardsiella spp. (10.0%) and Salmonella spp. (3.5%) were the most frequent for free-range chickens. Bacteria isolated from laying hens and free-range chickens showed higher susceptibility to tetracycline, ampicillin, norfloxacin, amoxicillin+clavulanic acid, ertapenem, imipenem and meropenem. Sixty-nine (45.4%) isolates with multidrug resistance were observed in laying hens and 36 (18%) from free-range chickens. The genes detected in the samples from laying hens were CTX-M in eight isolates with the blaCTX-M1-like group (four E. coli and four Klebsiella spp.), blaCTX-M2-like identified in six isolates (two E. coli, three Klebsiella spp. and one Salmonella spp.), blaCTX-M8-like in seven isolates (six E. coli and one Klebsiella spp.), and the CMY-2 gene in nine E. coli and two Klebsiella spp. For free-range chickens, blaCTX-M1-like, blaCTX-M2-like e blaCMY-2 genes were observed in three E. coli. We conclude that the emergence and dissemination of bacteria producing resistance genes, especially the production of CTX-M and CMY in laying hen cloacae compared to free-range hens, alerts to the possible diffusion of these resistance genes at the human-animal interface and in the ecosystems studied.