Epidemiological analysis of human and animal originated Mycobacterium bovis subspecies by spoligotyping and mycobacterial interspersed Repetitive Unit-Variable Number of Tandem Repeat (MIRU-VNTR) methods

This study aims to investigate the genotypic similarities between human and animal-originated isolates by spoligotyping and 24 loci MIRU-VNTR for molecular epidemiological analysis of Mycobacterium bovis isolates. In this study, isolates were obtained between 2019 and 2022 from 58 humans and 50 bovines. Initially identified with the GenoType MTBC kit, all isolates were genotyped using spoligotyping and 24 loci Mycobacterial Interspersed Repetitive Unit-Variable Number of Tandem Repeat (MIRU-VNTR) methods and their lineage relationships were illustrated in the dendrogram. When subjected to the spoligotyping method, the human and animal-originated isolates were revealed eight distinct clusters and 29 different genotypes. Notably the most prevalent genotypes were SIT1118/SB0989 (19.23%), SIT482/SB0120 (16.35%), SIT685/SB0288 (12.5%) detected in both human and animal-originated isolates. SB1593 (12.5%) was exclusively identified in animal-originated isolates. Additional genotypes included SIT3529/SB0920, SIT1185/SB0897, SIT3710/SB1595, SIT688/SB0129, SIT3687/SB1625, SB0419, SB2466, SB1231, and SB2510. MIRU-VNTR analysis resulted in nine distinct clusters and 55 different genotypes. ETR-C, QUB2163b, QUB26, and Mtub04 exhibited the highest allelic diversity, while MIRU02, MIRU20, MIRU24, MIRU27, and MIRU39 did not display allelic diversity. When the molecular typing results of the 95 isolates, tested with all three methods, 93.7 % agreement was observed between methods. In conclusion, it was determined that both tests could be safely employed. The presence of similar genotypes in humans and animals underscores the potential zoonotic transmission of Mycobacterium bovis.