title: Sputum bacterial load predicts multidrug-resistant tuberculosis in retreatment patients: a case-control study.
abstract: Rapid and effective diagnosis of multidrug-resistant tuberculosis (MDR-TB) is an essential component of global tuberculosis (TB) control, but most MDR-TB cases are still not diagnosed.
  
  
  
  To assess whether patient sputum bacterial load can be used to identify patients at increased risk of MDR-TB.
  
  
  
  We used a case-control study and multivariable logistic regression models to investigate associations between MDR-TB and sputum bacterial load, as measured by semi-quantitative microscopy and automated time to detection (TTD) of liquid culture. We assessed data from retreatment TB patients with MDR-TB (cases) and from those without MDR-TB (controls) at a reference laboratory in Cameroon.
  
  
  
  MDR-TB was associated with a smear microscopy grade of 3+ (OR 21.9, 95%CI 6.2-76.8) or 2+ (OR 10.8, 95%CI 2.9-40.7), compared to a result of 1+, scanty or smear-negative among 80 MDR-TB cases and 521 controls. MDR-TB was associated with automated TTD of ⩿160 h (OR 2.2, 95%CI 1.1-4.7) compared to >160 h among a subpopulation of 47 cases and 350 controls.
  
  
  
  A higher sputum bacterial load is associated with MDR-TB in retreatment patients in Cameroon.
authors.affiliation: Tuberculosis Reference Laboratory Bamenda, Bamenda, Cameroon; German International Cooperation, Yaounde, Cameroon.
authors.forename: M S
authors.initials: MS
authors.lastname: Sander
authors.affiliation: Tuberculosis Reference Laboratory Bamenda, Bamenda, Cameroon.
authors.forename: C Y
authors.initials: CY
authors.lastname: Vuchas
authors.affiliation: Tuberculosis Reference Laboratory Bamenda, Bamenda, Cameroon.
authors.forename: H N
authors.initials: HN
authors.lastname: Numfor
authors.affiliation: Tuberculosis Reference Laboratory Bamenda, Bamenda, Cameroon.
authors.forename: A N
authors.initials: AN
authors.lastname: Nsimen
authors.affiliation: National Tuberculosis Control Programme, Yaounde, Cameroon.
authors.forename: J-L F
authors.initials: JL
authors.lastname: Abena
authors.affiliation: Independent Consultant, Yaounde, Cameroon.
authors.forename: J
authors.initials: J
authors.lastname: Noeske
authors.affiliation: Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium; International Union Against Tuberculosis and Lung Disease, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Van Deun
authors.affiliation: Institute of Ageing and Chronic Disease and School of Veterinary Science, University of Liverpool, Leahurst, UK.
authors.forename: K L
authors.initials: KL
authors.lastname: Morgan
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use; D058491:Bacterial Load; D002163:Cameroon / Q000453:epidemiology; D016022:Case-Control Studies; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000302:isolation & purification; D019233:Retreatment; D013183:Sputum / Q000382:microbiology*; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000453:epidemiology*
chemical_list: D000995:Antitubercular Agents