MIRU-VNTR analysis of Mycobacterium simiae from Iran

Background and Objectives: Mycobacterium simiae, one of the infrequently isolated NTM from human clinical samples, has been described in Iran.M. simiae can be transmitted to patients from soil and water sources, however, in Iran the epidemiology of M. simiae has not been well characterized. Therefore, the present study investigated the prevalence and types of clinical isolates of M. simiae using VNTR-genotyping at one of the major tertiary care centers in Iran. Materials and Methods: In this study, during2018-2019, among 500 samples, M. simiae isolates were detected by PCR-RFLP method .Isolates were genetically characterized using 15-locus based MIRU-VNTR typing. VNTR sequences were amplified by specific primers using PCR technique.After confirming the PCR amplification using electrophoresis, their bonds on agarose gel were analyzed. Results: Among 500 samples, 30 M. simiae isolates were collected. According to the 15 locus VNTR analysis,it was found that 14 loci were present in genome of Mycobacterium simiae. Only MIRU16 loci was not found in any of the isolates. Thus, this locus demonstrated high discriminatory power for differentiation between M. simiae and M. tuberculosis complex. Conclusion: The present study showed MIRU16 loci has a high discriminatory to distinguish between M. simiae and M. tuberculosis complex and MIRU-VNTR genotyping could be a valuable tool for typing and epidemiological research. The results also showed that this method had a great potential to differentiate those strains with high phenotypic similarity.