title: Assessing Local Risk of Rifampicin-Resistant Tuberculosis in KwaZulu-Natal, South Africa Using Lot Quality Assurance Sampling.
abstract: BACKGROUND
  KwaZulu-Natal (KZN) has the highest burden of notified multidrug-resistant tuberculosis (MDR TB) and extensively drug-resistant (XDR) TB cases in South Africa. A better understanding of spatial heterogeneity in the risk of drug-resistance may help to prioritize local responses.
  
  
  METHODS
  Between July 2012 and June 2013, we conducted a two-way Lot Quality Assurance Sampling (LQAS) study to classify the burden of rifampicin (RIF)-resistant TB among incident TB cases notified within the catchment areas of seven laboratories in two northern and one southern district of KZN. Decision rules for classification of areas as having either a high- or low-risk of RIF resistant TB (based on proportion of RIF resistance among all TB cases) were based on consultation with local policy makers.
  
  
  RESULTS
  We classified five areas as high-risk and two as low-risk. High-risk areas were identified in both Southern and Northern districts, with the greatest proportion of RIF resistance observed in the northernmost area, the Manguzi community situated on the Mozambique border.
  
  
  CONCLUSIONS
  Our study revealed heterogeneity in the risk of RIF resistant disease among incident TB cases in KZN. This study demonstrates the potential for LQAS to detect geographic heterogeneity in areas where access to drug susceptibility testing is limited.
authors.affiliation: Clinical and Biomedical Tuberculosis Research Unit, Medical Research Council, Durban, South Africa.
authors.forename: Christine L
authors.initials: CL
authors.lastname: Heidebrecht
authors.affiliation: Division of Tuberculosis Elimination, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Podewils
authors.affiliation: KwaZulu-Natal Research Institute for Tuberculosis and HIV, Durban, South Africa.
authors.forename: Alexander
authors.initials: A
authors.lastname: Pym
authors.affiliation: School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Thuli
authors.initials: T
authors.lastname: Mthiyane
authors.affiliation: Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Ted
authors.initials: T
authors.lastname: Cohen
mesh_terms: D000293:Adolescent; D000328:Adult; D000995:Antitubercular Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011786:Quality Control; D012189:Retrospective Studies; D012293:Rifampin / Q000627:therapeutic use*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013019:South Africa / Q000453:epidemiology; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents; D012293:Rifampin