title: Utility of mycobacterial interspersed repetitive unit typing for differentiating multidrug-resistant Mycobacterium tuberculosis isolates of the Beijing family.
abstract: Mycobacterial interspersed repetitive unit (MIRU) typing has been found to allow rapid, reliable, high-throughput genotyping of Mycobacterium tuberculosis and may represent a feasible approach to study global M. tuberculosis molecular epidemiology. To evaluate the use of MIRU typing in discriminating drug-resistant M. tuberculosis strains of the Beijing genotype family, 102 multidrug-resistant (MDR) clinical isolates and 253 randomly selected non-MDR isolates collected from 2000 to 2003 in Hong Kong were subjected to 12-locus MIRU typing, spoligotyping, and IS6110 restriction fragment length polymorphism (RFLP) typing. Spoligotyping showed that 243 (68.5%) of 355 isolates belonged to Beijing family genotype. MIRU typing showed lower discrimination in differentiating between the Beijing family strains (Hunter-Gaston discriminative index [HGI] of 0.8827) compared with the IS6110 RFLP method (HGI = 0.9979). For non-Beijing strains, MIRU typing provided discrimination (HGI = 0.9929) comparable to that of the RFLP method (HGI = 0.9961). There was no remarkable difference in discrimination power between the two methods in differentiating both within and between MDR and non-MDR strains of M. tuberculosis. Dendrograms constructed with the MIRU typing data showed a clear segregation between the Beijing and non-Beijing genotype. Addition of RFLP to MIRU typing offered a higher discrimination ability (92.6%) than did addition of MIRU typing to RFLP (40.0%). This supported the potential use of this method to analyze the global genetic diversity of MDR M. tuberculosis strains that may be at different levels of evolutionary divergence.
authors.affiliation: Tuberculosis Reference Laboratory, Public Health Laboratory Service Branch, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, Kowloon, Hong Kong. kmkam@dh.gov.hk
authors.forename: Kai Man
authors.initials: KM
authors.lastname: Kam
authors.forename: Chi Wai
authors.initials: CW
authors.lastname: Yip
authors.forename: Lai Wa
authors.initials: LW
authors.lastname: Tse
authors.forename: Kin Lai
authors.initials: KL
authors.lastname: Wong
authors.forename: Tak Kam
authors.initials: TK
authors.lastname: Lam
authors.forename: Kristin
authors.initials: K
authors.lastname: Kremer
authors.forename: Betty Kam Yan
authors.initials: BK
authors.lastname: Au
authors.forename: Dick
authors.initials: D
authors.lastname: van Soolingen
mesh_terms: D015373:Bacterial Typing Techniques; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000032:analysis; D005838:Genotype; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D020071:Interspersed Repetitive Sequences / Q000235:genetics*; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics; D009841:Oligonucleotides / Q000032:analysis; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D018088:Tuberculosis, Multidrug-Resistant / Q000453:epidemiology / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000382:microbiology
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D009841:Oligonucleotides