First insight into the genetic population structure of Mycobacterium tuberculosis isolated from pulmonary tuberculosis patients in Egypt

The present study aimed to assess the population structure of Mycobacterium tuberculosis (MTB) isolates from Egypt. A total of 230 MTB isolates were analysed using spoligotyping, large sequence polymorphism (LSPs), mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing and multi-locus sequence typing (MLST). The majority of isolates (93.0%) belonged to lineage 4, including 44.3, 13.4 and 10.8% of the ill-defined T clade, LAM and Haarlem families, respectively, and lineage 3 was identified in 7.0% of the isolates. MIRU-VNTRs typing allowed efficient discrimination of the spoligotype-defined clusters, including spoligo-international types (SIT) 53, 34, and 4, into 56 patterns, including 13 clusters and 43 unique patterns. A new SNP at position 311614 was identified in all six isolates to form the biggest MIRU-VNTR cluster, which suggested a recent clonal expansion. This SNP could possibly be used as a genetic marker for robust discriminations of Egyptian MTB isolates belonging to SIT53. The combination of spoligotyping, 12 MIRU-VNTRs loci and MLST provided insight into the genetic diversity and transmission dynamics of the Egyptian MTB genotypes and could be a key to implementation of effective control measures by public health authorities.