Molecular characterization of Listeria monocytogenes from beef samples and cattle slaughterhouses located in the Federal District, Brazil

ABSTRACT:

The aim of the study was the analysis of Listeria monocytogenes strains in beef samples as well as slaughterhouse environment, located in the Federal District, promote serotyping by polymerase chain reaction (PCR), perform antibiotic susceptibility and submit the strains to Pulsed-field gel electrophoresis (PFGE). A total of 125 beef samples were analyzed, 45 samples of carcasses swabs and 43 swab samples. It detected 13 strains of Listeria monocytogenes, 11 in beef samples. and 2 in slaughterhouse environment. No carcass swabs strains were isolated. Among the 13 strains of L. monocytogenes six strains of serotype 4b were found, five serotype 1/2c and two strains of serotype 1/2a. Among the 11 strains of L. monocytogenes found in beef, one (9.1%) strain showed resistance to erythromycin, one (9.1%) strain to gentamicin, one to ciprofloxacin (9.1%) and all strains (100%) were resistant to nalidixic acid. The two strains coming from the slaughterhouse drains, all (100%) were resistant to nalidixic acid and Sulfonamides. The analysis by pulsed field gel electrophoresis (PFGE) showed 13 different pulsotypes; they were grouped into three different clonal groups, coincidentally correlated with the three different serotypes found, what suggests a widespread dissemination of these profiles in the Federal District, Brazil.

INDEX TERMS:
Listeria monocytogenes; pulsed-field gel electrophoresis; PFGE; listeriosis; meat, antibiogram