Contamination and antimicrobial resistance profile of Escherichia coli in chicken carcasses from public markets in Maranhão

Abstract

Contamination of chicken meat sold in public markets is a public health concern. The objective of this study was to identify contamination and evaluate the antimicrobial resistance profile of Escherichia coli in chicken carcasses from public markets in the North Mesoregion of Maranhão. A total of 160 freshly slaughtered chicken carcasses were collected in 16 markets in six municipalities in the microregions of Itapecuru-Mirim and São Luís. The samples were analyzed for the presence of E. coli using counting thermotolerant coliforms and classified according to the ANVISA microbiological standard. Of all the samples, 134 (83.75%) were considered unacceptable for consumption, according to Brazilian health legislation.  Bacteria were isolated from the positive samples, and 50 isolates were tested for susceptibility to 15 antimicrobial principles using the disc diffusion method. The results confirm the presence of E. coli, with counts ranging from 10¹ to 10⁸ NMP/g. The isolates showed resistance to neomycin (49/50, 98%), streptomycin (48/50, 96%), sulfonamides (47/50, 94%), nitrofurantoin (45/50, 90%), cefazolin (43/50, 86%), and tetracycline (43/50, 86%). No antibiotic was effective against the isolates, which were resistant to more than 3 antimicrobial classes considered resistant to multiple drugs (MDR). Therefore, chicken meat sold in public markets in Maranhão presents unsatisfactory conditions for consumption and risk of transmission of E. coli with an MDR profile.