Household contact investigation of multidrug-resistant and extensively drug-resistant tuberculosis in a high HIV prevalence setting

Int J Tuberc Lung Dis. 2011 Sep;15(9):1170-5, i. doi: 10.5588/ijtld.10.0781.


Setting: Multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) are now a nationwide epidemic in South Africa. Epidemiological data suggest nosocomial transmission as the primary route of spread; however, transmission among household contacts has not yet been investigated.

Objective: To determine the incidence rates of MDR- and XDR-TB among household contacts of MDR- and XDR-TB index cases diagnosed between January 2005 and September 2008 in a high human immunodeficiency virus prevalence setting.

Design: Prospective, observational study evaluating adult household contacts for active TB by culture and drug susceptibility testing at index case diagnosis and again 1 year later. Outcomes were incidence and time to diagnosis of MDR- and XDR-TB.

Results: A total of 1766 contacts of 221 MDR-TB and 287 XDR-TB index cases were screened. Of 793 contacts of MDR-TB index cases, 14 (1.8%) were diagnosed with MDR-TB (incidence 1765/100 000); 19 (2.0%) of 973 XDR-TB contacts had XDR-TB (incidence 1952/100 000). Median time to diagnosis of household cases was 70 days (interquartile range 57-89).

Conclusion: Incidence rates of MDR- and XDR-TB among household contacts were extremely high, with most secondary cases occurring shortly after the diagnosis of the index case. Active case finding of drug-resistant TB is a high-yield public health activity and must be a priority, as early diagnosis may stem further disease spread and improve survival.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Antitubercular Agents / pharmacology*
  • Extensively Drug-Resistant Tuberculosis / diagnosis
  • Extensively Drug-Resistant Tuberculosis / drug therapy
  • Extensively Drug-Resistant Tuberculosis / epidemiology*
  • Family Characteristics
  • Female
  • Follow-Up Studies
  • HIV Infections / epidemiology*
  • Humans
  • Incidence
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Prevalence
  • Prospective Studies
  • South Africa / epidemiology
  • Time Factors
  • Tuberculosis, Multidrug-Resistant / diagnosis
  • Tuberculosis, Multidrug-Resistant / drug therapy
  • Tuberculosis, Multidrug-Resistant / epidemiology*
  • Young Adult


  • Antitubercular Agents