A surveillance study was carried out to determine the prevalence of Listeria spp. in traditional dairy products in Chahar Mahal & Bakhtiyari province, Iran. From February 2009 to February 2010, a total of 290 samples of various traditional dairy products were obtained from randomly selected retail stores located in 6 major cities of the province. Using cultural method, 21 samples (7.2%) were found positive for Listeria spp. The highest prevalence of Listeria was found in traditional ice-cream (16.7%), followed by cheese (15.0%), butter (7.5%), and kashk (2.2%) samples. The overall prevalence of Listeria was 7.2%, in which L. innocua was the most commonly recovered species (66.6%); the remaining isolates were identified as L. monocytogenes (23.8%), L. murrayi (4.8%) and L. seeligeri (4.8%). All 5 Listeria strains identified as L. monocytogenes were also positive using polymerase chain reaction (PCR). Susceptibilities of the 21 strains to nine antimicrobial drugs were determined using the disk diffusion assay. All isolates were resistant to one or more antimicrobial agents. Six strains (28.6%) were resistant to a single and 5 strains (23.8%) showed resistance to two antimicrobial agents. Multi-drug resistance was established in 23.8% of Listeria strains. Resistance to nalidixic acid was the commonest finding (85.7%), followed by resistance to penicillin (47.6%), and tetracycline (33.3%). The results provide information about the contamination levels of traditional dairy products in one of the provinces of Iran and highlight the emergence of multi-drug resistant Listeria in the environment.
کلید واژگان :antimicrobial resistance, dairy products, Iran, Listeria spp
ارزش ریالی : 600000 ریال
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