Molecular fingerprinting of isoniazid-resistant Mycobacterium tuberculosis isolates from chest diseases hospital in Kuwait.

Touchdown double-repetitive-element-PCR (DRE-PCR) was carried out for typing 38 consecutive isoniazid-resistant Mycobacterium tuberculosis strains isolated at Chest Diseases Hospital, Kuwait, during 1998-2000. The polymorphism at codon 463 in the katG gene was also determined and correlated with genotypic relationships among the isolates. The isolates exhibited 21 distinct patterns in DRE-PCR. Nearly half of the isolates (18 of 38) exhibited unique patterns. Majority of isolates (16 of 20) yielding multiple DNA fragments in DRE-PCR were unique strains while most of the isolates (16 of 18) yielding a single DNA fragment in DRE-PCR clustered together. The prevalence of L463 in the katG gene was much higher in isolates from Middle Eastern (mostly Kuwaiti) patients than is reported for this ethnic group. The data indicate the possibility of some strains of South Asian/Southeast Asian origin spreading among local populations.