Detecção de Listeria monocytogenes em produtos cárneos no Tocantins e potencial uso de leveduras selvagens amazônicas como agentes de biocontrole

Abstract

Foodborne and Waterborne Diseases (FWD) are a group of infections or poisonings caused by pathogenic microorganisms present in food and water. Among these, we can highlight the bacterium Listeria monocytogenes, which causes listeriosis, a serious disease in humans, with high rates of hospitalization and mortality. This study aimed to detect the presence and evaluate the formation of biofilms of L. monocytogenes in commercially handled meat products available to consumers in the state of Tocantins, and the potential for inhibition of yeasts isolated from Amazonian fruits in the production of mycocins and sensitivity to antimicrobial compounds. Sixty samples of ready-to-eat meat products from the largest municipalities in the north, south and central regions of the state were analyzed using the official methodology of the Ministry of Agriculture (ISO 11290:2017) for the detection of L. monocytogenes. The isolates suggestive of the pathogenic bacteria were submitted to confirmation by polymerase chain reaction and three isolates were subjected to partial amplification of the 16S rRNA gene, followed by sequencing. The biofilm formation capacity was evaluated by growth in a 96-well microplate, followed by staining with crystal violet, and reading performed in Elisa with absorbance at 570 nm. The antagonism of yeasts against L. monocytogenes ATCC 7644 was evaluated by the "Cross-streak" method, and the antibiotic sensitivity test was also performed by disk diffusion. As a result, it was observed that 38% of the analyzed samples were contaminated with L. monocytogenes, with the northern region having the highest prevalence (65%). Approximately 35% of the isolates formed biofilms, of which 25% showed weak capacity, 37.5% moderate capacity and 37.5% strong capacity to form biofilms. Of the 185 yeasts evaluated, none showed antagonism against the L. monocytogenes strain. In the antimicrobial sensitivity test, resistance of the isolated L. monocytogenes strains to gentamicin – 10 μg (60%), tetracycline – 30 μg (13.4%), trimethoprim- sulfamethoxazole – 25 μg (80%), rifampicin – 10 μg (53.4%). All 30 strains were sensitive to penicillin, and only one isolate was resistant to ampicillin and chloramphenicol. The research serves a region lacking updated data on the occurrence of the pathogen, also seeking solutions to the problems of food contamination in the richness of Amazonian biodiversity.