Characteristics of multidrug-resistant Mycobacterium tuberculosis in Taiwan: a population-based study.

A population-based study was performed to characterize the genotype and drug-resistant patterns of multidrug-resistant tuberculosis (MDR-TB) in Taiwan. From 2007 to 2008, we analyzed 494 MDR Mycobacterium tuberculosis complex isolates using spacer oligonucleotide typing and drug susceptibility testing. The majority of cases occurred in the age groups of 45-54 (24.3%) and ≥65 (23.1%). Of the 494 MDR isolates, 25.1% were resistant to ethambutol, 15.6% were resistant to streptomycin, 27.1% were resistant to all four first-line anti-tuberculosis drugs, 28.9% were resistant to ofloxacin, and 8.7% were extensively drug-resistant (XDR). Compared with the SpolDB4, 86 spoligotypes were identified in 492 isolates. We observed 427 (86.8%) isolates belonging to 49 known spoligotypes and 65 isolates (13.2%) in 37 undesignated spoligotypes. Beijing lineages (50.0%) were the predominant genotype, followed by Haarlem (18.2%) and East-African-Indian (EAI) (5.7%). Geographically, Beijing lineages were predominant in all regions, whereas Haarlem lineages were predominant only in the east (28.1%) and EAI (11.3%) only in the south. Beijing lineages are statistically associated with MDR in younger age groups and eastern Taiwan. Furthermore, we found that Beijing ST1 (46.1%), Haarlem3 ST50 (7.1%) and ST742 (4.7%), and EAI2_MANILA ST19 (3.9%) were the prevalent groups. Thus, continuous surveillance with more thorough genotyping and epidemiological investigation is crucial for the prevention of further dissemination, the determination of the temporal and spatial trends of multi-drug resistance, and the emergence of XDR-TB in Taiwan.