title: Minimal inhibitory concentration of isoniazid in isoniazid-resistant Mycobacterium tuberculosis isolates from children.
abstract: The aim of the study presented here was to determine the minimal inhibitory concentration of isoniazid for strains of isoniazid-resistant or multidrug-resistant Mycobacterium tuberculosis isolated from children in the Western Cape Province of South Africa. During the period March 2003-October 2005, 45 INH-resistant M. tuberculosis isolates (21 also rifampicin-resistant) were cultured from children less than 13 years of age. Drug susceptibility testing by the radiometric BACTEC 460 method found 11 isolates resistant at 0.1 microg/ml, 27 resistant at 0.2 microg/ml, and seven resistant at > or =5 microg/ml. Thus, the minimal inhibitory concentration of isoniazid for more than 80% of the isoniazid-resistant strains isolated from children in this study was relatively low and could be exceeded by high-dose (15-20 mg/kg) isoniazid regimens.
authors.affiliation: Desmond Tutu Tuberculosis Centre, Department of Paediatrics and Child Health, Faculty of Health Sciences, Stellenbosch University, P.O. Box 19063, Tygerberg 7505, South Africa. hss@sun.ac.za
authors.forename: H S
authors.initials: HS
authors.lastname: Schaaf
authors.forename: T C
authors.initials: TC
authors.lastname: Victor
authors.forename: E
authors.initials: E
authors.lastname: Engelke
authors.forename: W
authors.initials: W
authors.lastname: Brittle
authors.forename: B J
authors.initials: BJ
authors.lastname: Marais
authors.forename: A C
authors.initials: AC
authors.lastname: Hesseling
authors.forename: P D
authors.initials: PD
authors.lastname: van Helden
authors.forename: P R
authors.initials: PR
authors.lastname: Donald
mesh_terms: D000293:Adolescent; D000995:Antitubercular Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D007223:Infant; D007538:Isoniazid / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000302:isolation & purification; D012293:Rifampin / Q000494:pharmacology; D014376:Tuberculosis / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D007538:Isoniazid; D012293:Rifampin