title: Moxifloxacin resistance in the F15/LAM4/KZN extensively drug-resistant strain of Mycobacterium tuberculosis.
abstract: OBJECTIVE
  Moxifloxacin (MXF) has been advocated for the treatment of extensively drug-resistant (XDR) tuberculosis despite resistance to older-generation fluoroquinolones. We investigated the relationship between the minimum inhibitory concentration (MIC) of MXF and mutations in the gyrA and gyrB genes in Mycobacterium tuberculosis (MTB) isolates from KwaZulu-Natal (KZN) Province of South Africa.
  
  
  METHODS
  MICs of 56 MTB isolates were compared to the mutations in the quinolone resistance-determining region known to confer fluoroquinolone resistance. Isolates were genotyped by IS6110 restriction fragment length polymorphism analysis.
  
  
  RESULTS
  The circulating F15/LAM4/KZN XDR strain circulating in KZN Province harbored the A90V mutation and displayed high-level resistance with MICs of 8 mg/L for ciprofloxacin and ofloxacin and ≥1 mg/L for MXF.
  
  
  CONCLUSIONS
  The inclusion of MXF in XDR-TB treatment regimens requires careful consideration in our setting, where clinical outcome data in MXF-containing regimens are unavailable.
authors.affiliation: Department of Infection Prevention and Control, Nelson R Mandela School of Medicine, School of Laboratory Medicine and Medical Science, College of Health Science, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Navisha
authors.initials: N
authors.lastname: Dookie
authors.affiliation: Department of Infection Prevention and Control, Nelson R Mandela School of Medicine, School of Laboratory Medicine and Medical Science, College of Health Science, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: A Willem
authors.initials: AW
authors.lastname: Sturm
authors.affiliation: Department of Infection Prevention and Control, Nelson R Mandela School of Medicine, School of Laboratory Medicine and Medical Science, College of Health Science, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Prashini
authors.initials: P
authors.lastname: Moodley
keywords: drug-resistance; fluoroquinolones; strain typing; susceptibility testing