title: Detection of multiple strains of Mycobacterium tuberculosis using MIRU-VNTR in patients with pulmonary tuberculosis in Kampala, Uganda.
abstract: BACKGROUND
  Many studies using DNA fingerprinting to differentiate Mycobacterium tuberculosis (MTB) strains reveal single strains in cultures, suggesting that most disease is caused by infection with a single strain. However, recent studies using molecular epidemiological tools that amplify multiple targets have demonstrated simultaneous infection with multiple strains of MTB. We aimed to determine the prevalence of MTB multiple strain infections in Kampala, and the impact of these infections on clinical presentation of tuberculosis (TB) and response to treatment.
  
  
  METHODS
  A total of 113 consecutive smear and culture positive patients who previously enrolled in a house-hold contact study were included in this study. To determine whether infection with multiple MTB strains has a clinical impact on the initial presentation of patients, retrospective patient data (baseline clinical, radiological and drug susceptibility profiles) was obtained. To determine presence of infections with multiple MTB strains, MIRU-VNTR (Mycobacterial Interspersed Repetitive Unit-Variable-Number Tandem Repeats) -PCR was performed on genomic DNA extracted from MTB cultures of smear positive sputum samples at baseline, second and fifth months.
  
  
  RESULTS
  Of 113 patients, eight (7.1%) had infection with multiple MTB strains, coupled with a high rate of HIV infection (37.5% versus 12.6%, p = 0.049). The remaining patients (105) were infected with single MTB strains. The proportions of patients with MTB smear positive cultures after two and five months of treatment were similar. There was no difference between the two groups for other variables.
  
  
  CONCLUSIONS
  Infection with multiple MTB strains occurs among patients with first episode of pulmonary tuberculosis in Kampala, in a setting with high TB incidence. Infection with multiple MTB strains had little impact on the clinical course for individual patients. This is the first MIRU-VNTR-based study from in an East African country.
authors.affiliation: Department of Pediatrics, Boston Medical Center, Boston University, Boston, USA.
authors.forename: Katherine R
authors.initials: KR
authors.lastname: Dickman
authors.forename: Lydia
authors.initials: L
authors.lastname: Nabyonga
authors.forename: David P
authors.initials: DP
authors.lastname: Kateete
authors.forename: Fred A
authors.initials: FA
authors.lastname: Katabazi
authors.forename: Benon B
authors.initials: BB
authors.lastname: Asiimwe
authors.forename: Harriet K
authors.initials: HK
authors.lastname: Mayanja
authors.forename: Alphonse
authors.initials: A
authors.lastname: Okwera
authors.forename: Christopher
authors.initials: C
authors.lastname: Whalen
authors.forename: Moses L
authors.initials: ML
authors.lastname: Joloba
mesh_terms: D000328:Adult; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D008297:Male; D018598:Minisatellite Repeats; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D015995:Prevalence; D017422:Sequence Analysis, DNA; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology / Q000382:microbiology*; D014454:Uganda / Q000453:epidemiology
chemical_list: D004269:DNA, Bacterial