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Occurrence and antimicrobial resistance patterns of Listeria monocytogenes isolated from vegetables

de Vasconcelos Byrne, Vanessa, Hofer, Ernesto, Vallim, Deyse Christina, de Castro Almeida, Rogeria Comastri
Brazilian journal of microbiology 2016 v.47 no.2 pp. 438-443
Listeria monocytogenes, antibiotic resistance, benzylpenicillin, food pathogens, health hazards, microbiology, polymerase chain reaction, raw vegetables, ready-to-eat foods, serotypes, temperature, vegetables, virulence
Although the consumption of fresh and minimally processed vegetables is considered healthy, outbreaks related to the contamination of these products are frequently reported. Among the food-borne pathogens that contaminate vegetables is Listeria monocytogenes, a ubiquitous organism that exhibits the ability to survive and multiply at refrigerated temperatures. This study aimed to evaluate the occurrence of L. monocytogenes in vegetables as well as the antimicrobial resistance of isolates. The results showed that 3.03% of samples were contaminated with L. monocytogenes, comprising 2.22% of raw vegetables and 5.56% of ready-to-eat vegetables. Multiplex PCR confirmed the virulence potential of the isolates. Antimicrobial resistance profiling showed that 50% of the isolates were susceptible to the antibiotics used. The resistance of one isolate to penicillin G, a commonly employed therapeutic agent, and the presence of serotype 4b, a serotype commonly associated with food-borne outbreaks, could be potential health hazards for consumers.