Twenty Years ofListeriain Brazil: Occurrence ofListeriaSpecies andListeria monocytogenesSerovars in Food Samples in Brazil between 1990 and 2012

Abstract

Listeriaspp. isolated from different food products and collected from 12 Brazilian states were sent to the Laboratory of Bacterial Zoonoses (Oswaldo Cruz Institute, Brazil) for identification. The aims of this study were to characterize these isolates, from 1990 to 2012, by using biochemical, morphological, and serotyping tests, and to analyze the distribution ofL. monocytogenesserotypes on different food products and geographical locations. Serotyping was performed using polyclonal somatic and flagellar antisera. Of 5953 isolates, 5770 were identified asListeriaspp., from which 3429 (59.4%) wereL. innocua, 2248 (38.9%) wereL. monocytogenes, and 93 (1.6%) were otherListeriaspp.L. innocuawas predominantly isolated from 1990 to 2000, whileL. monocytogeneswas from 2001 to 2012. Regarding the serotype distribution in the foods, serotypes 1/2a and 4b were most common in processed meat and ready-to-eat products, respectively; serotypes 1/2a, 1/2b, and 4b were the most common in nonprocessed meat. The results above confirm the presence of the main serotypes ofL. monocytogenesin different parts of the food chain from three regions of the country and emphasize the importance of improving the control measures, as tolerance zero policy and microbiological surveillance in Brazil.