The Determination of the Antimicrobial Susceptibility and Antimicrobial Resistance Gene Patterns in L. monocytogenes

Background: Listeriosis, a fatal disease for vulnerable groups, has become common in the last decade due to extensive consumption of dairy and meat products. Listeria monocytogenes is an important foodborne opportunistic human pathogen and causal agent of listeriosis. There is a little information about the antibiotic susceptibility and resistance genes pattern of L. monocytogenes. Methods: The present study aimed to evaluate the antibiotic susceptibility and resistance genes pattern of L. monocytogenes isolates from different clinical and environmental sources. Results: The results showed that 88% of the isolates are resistant to streptomycin and 83% to TMP-SMX. Polymerase chain reaction (PCR) amplification of resistance genes showed that the prevalence of ermA, ermB, strA, tetS, tetA, and ermC genes in L. monocytogenes isolates were 0% (0/55), 10.9% (6/55), 78.81% (43/55), 0% (0/55), 27.27% (15/55), and 0% (0/55), respectively. Conclusion: The resistance of the isolates to the antibiotics represents a potential public health risk and indicates the necessity of the bacteriological controls to reduce the contamination of the food samples.