Open AccessSpoligotyping of Mycobacterium tuberculosis Isolates from Pakistan Reveals Predominance of Central Asian Strain 1 and Beijing Isolates
Author(s) -
Zahra Hasan,
Mahnaz Tanveer,
Akbar Kanji,
Qaiser Hasan,
Solomon Ghebremichael,
Rumina Hasan
Publication year - 2006
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.44.5.1763-1768.2006
Subject(s) - mycobacterium tuberculosis , tuberculosis , incidence (geometry) , genotype , drug resistance , beijing , strain (injury) , population , virology , biology , extensively drug resistant tuberculosis , veterinary medicine , microbiology and biotechnology , medicine , genetics , china , gene , pathology , geography , environmental health , physics , archaeology , optics , anatomy
The estimated incidence of tuberculosis in Pakistan is 181 per 100,000; however, there is limited information onMycobacterium tuberculosis genotypes circulating in the country. We studied 314M. tuberculosis clinical isolates; of these, 197 (63%) isolates grouped into 22 different clusters, while 119 (37%) had unique spoligotypes. Eighty-nine percent of the isolates were pulmonary (Pul), and 11% were extrapulmonary (E-Pul). We identified Central Asian Strain (CAS), Beijing, T1, Latin American-Mediterranean, and East African-Indian genogroups. Beijing strains, reportedly the most prevalent spoligotype worldwide, constituted 6% of our strain population. The CAS1 strain comprised 121 (39%) of the study isolates. No difference was observed between clustered isolates from cases of Pul and E-Pul tuberculosis. However, E-Pul isolates included a greater number of unique spoligotypes than Pul isolates (P = 0.005). The overall percentage of drug resistance was 54%, and that of MDR strains was 40%. While CAS1 strains were not associated with drug resistance, the relative risk of MDR was significant in Beijing strains compared to the non-Beijing groups (95% confidence interval, 1.2 to 8.9). The fact that the predominant strain, CAS1, is not associated with drug resistance is encouraging and suggests that an effective tuberculosis control program should be able to limit the high incidence of disease in this region.