The Relationship ofYersinia Isolates Bioserotypeswith Minimum Inhibitory Concentration of Ampicillin, Cefazolin, and Cefotaxime

Background:Yersinia is a genus in the family Enterobacteriaceae that its species includeYersinia enterocolitica, Yersinia intermedia, Yersinia frederiksenii, and Yersinia kristensenii. Among these species, Yersinia enterocolitica is the most important one that causes various diseases such as gastroenteritis, mesenteric lymphadenitis, and erythema nodosum. Since antibiotic-resistance makes some problems in the treatment of diseases caused by these groups of bacteria, this study was designed to determine the relationship between serotypes and minimum inhibitory concentration (MIC) of Ampicillin, Cefazolin, and Cefotaxime in Yersinia isolates and also the sensitivity of Yersinia to these antibiotics. Methods: In this descriptive study, 50 different strains of Yersinia (39 ones isolated from human, environmental, and food resources of Iran, and 11 ones purchased from Pasteur Institute of Paris) were used to determine MIC of three selected antibiotics using broth macrodilution test. Results: Cefotaxim showed the lowest MIC (≤ 0.125μg/ml) indicating that it can be used as the most effective antibiotic against Yersinia-related infections. All the species showed 100% resistance to Ampicillin and very low sensitivity to Cefazolin. Conclusion: Among four studied species, Yersinia kristensenii and Yersinia frederiksenii were respectively the most sensitive and the most resistant species to Beta-lactam antibiotics. Yersinia enterocolitica and Yersinia intermedia compared to the others showed intermediate sensitivity.