Identificação molecular e resistência antimicrobiana de Escherichia coli patogênicas e Salmonella sp. isoladas de suínos criados no estado do Pará.

Abstract

In the northern region, pig farming is characterized as a complementary source of income, and with little attention to hygienic-sanitary care, which favors enteric bacterial infections that have a great impact on pig farming and some on collective health. In the Amazonian ecosystem, little is known about enterobacteria in slaughter pigs. Thus, the objective was to investigate the occurrence of pathogenic Escherichia coli and Salmonella sp. in pigs raised in the State of Pará, to determine the risk factors, besides verifying the antimicrobial resistance profile of pathogenic strains. 200 swine fecal swab samples were collected from 15 farms located in the Metropolitan Mesoregion of Belém and Northeast Paraense and processed at the Evandro Chagas Institute Enterobacterial Laboratory, Ananindeua, PA. For E. coli isolation, samples were sown in EC and GN broths, incubated and then seeded on MacConkey Agar. Suspected colonies were identified on TSI (Triple Sugar Iron Agar) for further biochemical characterization. The characterization of the pathotype was performed from amplification by PCR (Polymerase Chain Reaction) Multiplex technique. For isolation of Salmonella sp., Samples were inoculated into the Selenite Cystine and Rappaport enrichment broths and, after incubation, were sown in the selective culture media-indicators Salmonella-Shigella (SS) and on Xylose-LysineDescarboxylate (XLD) agar. . Suspicious colonies were identified on TSI for later biochemical identification and confirmed by PCR. The susceptibility to antimicrobial agents of the isolates was evaluated using the automated VITEK® 2 Compact system (bioMérieux). Data were tabulated and evaluated using statistical software Statistical Analysis System (SAS, 2019), using the chi-square statistical test (χ2) with a significance level of 5%. To determine the risk factors, the results of the records were tabulated and the odds ratios test used for each investigated variable, calculated considering as dependent variable the animal status (positive or negative) for the pathogenic bacterium. Of the 200 fecal swab specimens, 40.5% had pathogenic isolated E. coli identified by PCR, of which 26% enteropathogenic E. coli (EPEC), 11% enterohemorrhagic E. coli (EHEC), 11% E. coli enteroinvasoras (EIEC), in addition to 3% (6/200) with Salmonella sp .. Regarding the risk factors investigated, only the presence of other animal species and the material of the wood type houses were considered statistically significant. Among the E. coli isolates considered pathogenic, 72.62% showed sensitivity for all tested antimicrobials, 27.38% resistance for at least 1 tested antimicrobial and 26.19% of the samples showed multidrug resistance. The highest resistances were for Ampicillin (22.62%), Trimethoprim Sulfamethoxazole (19.04%), Cephalothin (16.66%) and Nalidixic Acid (13.09%). In addition, 7.14% for Ciprofloxacin, 5.95% for Cefuroxime, 3.57% for Nitrofurantoin, 2.38% for Ceftriaxone, Norfloxacin and Amoxiline and 1.9% for Ertapenem. Thus, it was possible to verify the occurrence of pathogenic E. coli and Salmonella sp. in pigs raised in the state of Pará; calling attention to the heterogeneity of the affected animals. In addition, resistance of these pathogenic strains was observed and there was a great concern regarding the selection of resistance genes in bacteria present in the microbiota of animals used as a food source.