Antimicrobial susceptibility and serotype distribution of Listeria monocytogenes isolates obtained from raw milk cheese samples sold in Nigde

Karadal F., YILDIRIM Y.

ANKARA UNIVERSITESI VETERINER FAKULTESI DERGISI, vol.61, no.4, pp.255-260, 2014 (SCI-Expanded) identifier


This study was designed to evaluate public health risks in respect to listeriosis due to consumption of local raw milk cheese sold in villages and public bazaars of Nigde. In addition, this study aims to contribute to the treatment process of listeriosis by determining serotype distribution and antimicrobial susceptibility profiles of the isolates. In the study, two of cheese (1 %) samples of total 200 raw milk cheese samples (100 white cheeses and 100 tulum cheeses) were found contamined with L. monocytogenes. Serotype distribution of the isolates were determined as 1/2a (white cheese isolate) and 4a (tulum cheese isolate). Finally, antimicrobial resistance profiles of the isolates against 11 antibiotics (tetracycline, ciprofloxacin, gentamicin, ampicillin, erythromycin, trimethoprim, vancomycin, chloramphenicol, nalidixic acid, penicillin G and sulphanilamide) were determined and the MIC values were specified by a microdilution method. Both of the isolates were found to be resistant to nalidixic acid but sensitive to the others analysed. As a result, although low L. monocytogenes prevalance rates were detected in this study, it is a public health concern to isolate serotype 1/2a which is secondly incriminated serotype to cause human listeriosis. In addition, it is important in terms of public health to continue surveillance of emerging antimicrobial resistance among L. monocytogenes isolated especially from foods of animal origin though incidence of antibiotic resistance in L. monocytogenes isolates is rare.