Determination of Nontuberculosis Mycobacteria Species Genotypes Present in Cattle Milk Samples Using 16S rRNA Gene Direct Sequencing

Background: Nontuberculosis Mycobacterium (NTM) is the most common bacterium transferred to human from cow milk and products. The presence of these bacteria in the cow's milk stands as a public health concern particularly among those individuals consuming raw milk and dairy products. In this study the determination of 16S rRNA gene sequence method was used in order to evaluate the amount of Non tuberculosis Mycobacterium incidence and determine its types in milk samples gathered from Isfahan province. Methods: The cetyltrimethylammonium bromide (CTAB) and phenol chloroform were used for DNA extraction in isolates recognized as Non tuberculosis Mycobacterium, then using designed primers, 16S rRNA polymerase chain reaction was done and the types were determined after sequencing. Findings: 9 cultures, out of 119 samples gathered from Isfahan farms, were recognized positive in which 8 samples had M. fortuitum and one of them was M. gordonae. Conclusion: NTM incidence was 8.6% in evaluated milk samples. By using polymerase chain reaction (PCR) with 16SrRNA and sequencing, the fortuitum isolate type I incidence was 88.9% and Gordonae type III incidence was 11.1%. PCR method and sequencing of 16S rRNA gene which were used in this study are able to recognize isolates up to 100%.