title: Drug resistance and IS6110-RFLP patterns of Mycobacterium tuberculosis in patients with recurrent tuberculosis in northern Thailand.
abstract: The emergence of drug resistant Mycobacterium tuberculosis has become a global threat to tuberculosis (TB) prevention and control efforts. This study aimed to determine the drug resistance profiles and DNA fingerprints of M. tuberculosis strains isolated from patients with relapsed or retreatment pulmonary TB in Chiang Rai province in northern Thailand. Significant differences in multidrug resistance (MDR) (P = 0.025) and resistance to isoniazid (P = 0.025) and rifampin (P = 0.046) between first and second registrations of patients with retreatment TB were found. However, there were no significant differences in resistance to any drugs in patients with relapsed TB. The rate of MDR-TB strains was 12.2% among new patients at first registration, 22.5% among patients with recurrence who had previously undergone treatment at second registration and 12.5% at third registration. Two retreatment patients whose initial treatment had failed had developed MDR-TB with resistance to all TB drugs tested, including rifampin, isoniazid, streptomycin and ethambutol. IS6110-RFLP analysis revealed that 66.7% (10/15 isolates) of MDR-TB belonged to the Beijing family. In most cases, IS6110-RFLP patterns of isolates from the same patients were identical in relapse and retreatment groups. However, some pairs of isolates from retreatment patients after treatment failure had non-identical IS6110-RFLP patterns. These results suggest that, after failure and default treatment, patients with retreatment tuberculosis have a significantly greater risk of MDR-TB, isoniazid and rifampin resistance than do other patients.
authors.affiliation: Department of Microbiology and Immunology, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Supaporn
authors.initials: S
authors.lastname: Sukkasem
authors.forename: Hideki
authors.initials: H
authors.lastname: Yanai
authors.forename: Surakameth
authors.initials: S
authors.lastname: Mahasirimongkol
authors.forename: Norio
authors.initials: N
authors.lastname: Yamada
authors.forename: Dhanida
authors.initials: D
authors.lastname: Rienthong
authors.forename: Prasit
authors.initials: P
authors.lastname: Palittapongarnpim
authors.forename: Srisin
authors.initials: S
authors.lastname: Khusmith
mesh_terms: D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000494:pharmacology; D016172:DNA Fingerprinting; D004251:DNA Transposable Elements; D024881:Drug Resistance, Bacterial; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D058889:Molecular Typing; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D012150:Polymorphism, Restriction Fragment Length; D012008:Recurrence; D013785:Thailand; D014397:Tuberculosis, Pulmonary / Q000382:microbiology*
chemical_list: D000995:Antitubercular Agents; D004251:DNA Transposable Elements