RESUMO
This study addressed the occurrence of Listeriamonocytogenes and Salmonella spp. in bovine carcasses at two slaughterhouses in southern Brazil. Then, the antimicrobial susceptibility profile and the virulence potential of the isolates were evaluated. Two hundred carcasses were sampled at four steps of the slaughter process, with L. monocytogenes being isolated in 12 and Salmonella spp. in 17 carcasses. All L. monocytogenes isolates carried the hlyA, prfA, plcA, plcB, actA, iap, mpl, inlA, inlB, inlC, and inlJ genes, while Salmonella spp. carried invA and hilA. Among the L. monocytogenes isolates, all of them presented virulence determinants and one showed multi-drug resistance. In relationship to Salmonella spp. isolates, many serogroups frequently related to outbreaks of foodborne diseases were identified and four isolates showed resistance to more than one antimicrobial agent. This data highlights the importance of a rigid hygienic-sanitary control during the slaughter process to reduce the risk of cross-contamination and lower the consumer exposure to L. monocytogenes and Salmonella spp. infections.
Assuntos
Microbiologia de Alimentos/métodos , Microbiologia de Alimentos/estatística & dados numéricos , Listeria monocytogenes , Carne/microbiologia , Salmonella , Matadouros , Animais , Antibacterianos/farmacologia , Brasil , Bovinos , Farmacorresistência Bacteriana Múltipla/genética , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/genética , Listeria monocytogenes/isolamento & purificação , Listeria monocytogenes/patogenicidade , Salmonella/efeitos dos fármacos , Salmonella/genética , Salmonella/isolamento & purificação , Salmonella/patogenicidade , Fatores de Virulência/genéticaRESUMO
Irrigation water has been recognized as an important microbial risk factor for fruits and vegetables in many production areas, but there is still a lack of information about how the microbiological quality of different irrigation water sources and climatic conditions influence the safety of vegetables produced in Brazil. This study evaluated the distribution of generic E. coli and the prevalence of E. coli O157:H7 in two different water sources (ponds and streams bordering farmlands and urban areas) used for irrigation and on commercially produced lettuces in Southern Brazil. We also evaluated the effect of agricultural factors and meteorological conditions in the potential contamination of water and produce samples. A longitudinal study was conducted on four farms during a year (July 2014 to August 2015). The results showed generic E. coli prevalence of 84.8% and 38.3% in irrigation water samples and on lettuces, respectively, indicating irrigation water as an important source of contamination of lettuces. No significant differences were detected in the counts of E. coli between the two different surface water sources. The climatic conditions, particularly rainfall and environmental temperature, have influenced the high concentration of E. coli. The highest loads of E. coli in irrigation water and on lettuces were found during the warmest time of the year. E. coli O157:H7 was detected by qualitative polymerase chain reaction (qPCR) in 13 water samples but only 4 were confirmed by isolation in culture media.