Genetic Diversity and Drug Resistance of Mycobacterium tuberculosis Complex Isolates and Nontuberculous Mycobacteria Identification from Presumptive Tuberculosis Cases in Oaxaca, Mexico

Tuberculosis (TB) is a re-emerging health problem worldwide. In Mexico, information about genetic diversity and drug resistance of Mycobacterium Tuberculosis complex (MTBc) is limited. Samples from 463 Presumptive TB cases were tested for TB by smear, culture and PCR, from which 19.2% were identify as MTBc and 16% as nontuberculous mycobacteria. MTBc isolates were characterized by Large Sequence Polymorphisms (LSPs), spoligotyping and MIRU-VNTR 24 loci typing methods. Clade designations showed 10 sub-lineages: Haarlem (35.7%), EAI (26.2%), LAM (9.5%), Ghana (4.8%), X (2.4%), New-1 (2.4%), H37Rv-like (7.1%), M. bovis (2.4%), S (7.1%), Uganda I (2.4%). The finding of EAI as one of the principal genotypes may be associated with high migration rates. Drug resistance was found in 35.71% of the isolates: 14.2% were multidrug-resistant (MDR-TB), 14.2% mono-resistant and 7.14% poly-resistant. This study provides the first description of genetic diversity and drug resistance profile of MTBc in Oaxaca, Mexico.