title: Drug resistance and genotypic analysis of Mycobacterium  tuberculosis strains from Thai tuberculosis patients.
abstract: The aim of this study was the molecular characterization of primary drug-resistant Mycobacterium tuberculosis strains in Thailand. We examined a group of M. tuberculosis isolates from newly registered tuberculosis (TB) cases, collected at the largest university hospital, the Siriraj Hospital, in Thailand. Of 76 selected drug-resistant M. tuberculosis strains recovered from previously untreated pulmonary TB patients whose sputum samples were sent to this hospital, 29 (38%) were single-drug resistant, 26(34%) multidrug resistant and two (2.6%) extensively drug resistant. Fifty (66%) strains belonged to Beijing genotype. The study demonstrated a severe problem of drug resistance among recently detected TB patients, and two large clusters of genetically similar strains indicated ongoing transmission of drug-resistant TB.
authors.affiliation: Department of Clinical Microbiology, Karolinska University Hospital and Karolinska Institute, Stockholm, Sweden.
authors.forename: Wattana
authors.initials: W
authors.lastname: Cheunoy
authors.forename: Melles
authors.initials: M
authors.lastname: Haile
authors.forename: Angkana
authors.initials: A
authors.lastname: Chaiprasert
authors.forename: Therdsak
authors.initials: T
authors.lastname: Prammananan
authors.forename: Mariana
authors.initials: M
authors.lastname: Cristea-Fernström
authors.forename: Martin
authors.initials: M
authors.lastname: Vondracek
authors.forename: Erja
authors.initials: E
authors.lastname: Chryssanthou
authors.forename: Sven
authors.initials: S
authors.lastname: Hoffner
authors.forename: Björn
authors.initials: B
authors.lastname: Petrini