Abstract
Infection and transmission of multidrug-resistant Mycobacterium tuberculosis (MDR-Mtb) and extensively drug-resistant M. tuberculosis (XDR-Mtb) is a serious health problem. We analyzed a total of 1,110 Mtb isolates in Osaka Prefecture and neighboring areas from April 2000 to March 2009. A total of 89 MDR-Mtb were identified, 36 (48.5%) of which were determined to be XDR-Mtb. Among the 89 MDR-Mtb isolates, 24 (27.0%) phylogenetically distributed into six clusters based on mycobacterial interspersed repetitive units-various number of tandem repeats (MIRU-VNTR) typing. Among these six clusters, the MIRU-VNTR patterns of four (OM-V02, OM-V03, OM-V04, and OM-V06) were only found for MDR-Mtb. Further analysis revealed that all isolates belonging to OM-V02 and OM-V03, and two isolates from OM-V04 were clonal. Importantly such genotypes were not observed for drug-sensitive isolates. These suggest that few but transmissible clones can transmit after acquiring multidrug resistance and colonize even in a country with a developed, well-organized healthcare system.
Highlights
The control of tuberculosis (TB) has become increasingly more urgent because of the emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDRTB)
The drug susceptibility patterns of 74 Multidrug-resistant Mycobacterium tuberculosis (MDR-M. tuberculosis (Mtb)) isolates were identified to investigate the prevalence of XDR-Mtb among MDR-Mtb isolates (Table 1) and 36 (48.6%) were determined to be XDR-Mtb
Non MDR-Mtb To bring out the genetic aspects of MDR-Mtb, we compared the cluster formation resulting from MIRU-VNTR genotyping and the frequency of Beijing lineage with those of populationbased non MDR-Mtb (Table2)
Summary
The control of tuberculosis (TB) has become increasingly more urgent because of the emergence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDRTB). Multidrug-resistant Mycobacterium tuberculosis (MDR-Mtb) is resistant to at least both isoniazid (INH) and rifampin (RFP), while extensively drug-resistant M. tuberculosis (XDR-Mtb) is resistant to both INH and RFP, in addition to any of the second-line injectable drugs (capreomycin, kanamycin [KM] or amikacin) and fluoroquinolone [3,4]. In principle, these resistant M. tuberculosis (Mtb) strains are thought to arise through the selection of mutated strains in response to inadequate chemotherapy [1,2,5,6]. Overall, Beijing strains of Mtb represent approximately 10% of MDR-Mtb isolates worldwide [14]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
