Mycobacterium tuberculosis Transmission Is Not Related to Household Genotype in a Setting of High Endemicity
- 1 May 2009
- journal article
- Published by American Society for Microbiology in Journal of Clinical Microbiology
- Vol. 47 (5), 1338-1343
- https://doi.org/10.1128/jcm.02490-08
Abstract
Among the different strains of Mycobacterium tuberculosis , Beijing has been identified as an emerging genotype. Enhanced transmissibility provides a potential mechanism for genotype selection. This study evaluated whether the Beijing genotype is more readily transmitted than other prevalent genotypes to children in contact with an adult tuberculosis (TB) index case in the child's household. We conducted a prospective, community-based study at two primary health care clinics in Cape Town, South Africa, from January 2003 through December 2004. Bacteriologically confirmed new adult pulmonary TB cases were genotyped by IS 6110 DNA fingerprinting; household contacts less than 5 years were traced and screened for M. tuberculosis infection and/or disease. A total of 187 adult index cases were identified from 174 households with children aged less than 5 years. Of 261 child contacts aged 0 to 5 years, 219 (83.9%) were completely evaluated and the isolate from the index case was successfully genotyped. M. tuberculosis infection (induration of ≥10 mm by Mantoux tuberculin skin test) was documented in 118/219 (53.9%) children; 34 (15.5%) had radiographic signs suggestive of active TB. There was no significant difference in the ratio of infected children among those exposed to the Beijing genotype (51/89; 57.3%) and those exposed to non-Beijing genotypes (55/115; 47.8%) (odds ratio, 1.5; 95% confidence interval, 0.8 to 2.7). Genotyping was successful for six children diagnosed with active TB; the isolates from only two children had IS 6110 fingerprints that were identical to the IS 6110 fingerprint of the isolate from the presumed index case. We found no significant association between the M. tuberculosis genotype and transmissibility within the household. However, undocumented M. tuberculosis exposure may have been a major confounding factor in this setting with a high burden of TB.Keywords
This publication has 39 references indexed in Scilit:
- Mycobacterium bovisBCG Immunization Induces Protective Immunity against Nine DifferentMycobacterium tuberculosisStrains in MiceInfection and Immunity, 2008
- The clinical consequences of strain diversity in Mycobacterium tuberculosisTransactions of the Royal Society of Tropical Medicine and Hygiene, 2008
- Progression to Active Tuberculosis, but Not Transmission, Varies byMycobacterium tuberculosisLineage in The GambiaThe Journal of Infectious Diseases, 2008
- Evidence that the Spread of Mycobacterium tuberculosis Strains with the Beijing Genotype Is Human Population DependentJournal of Clinical Microbiology, 2007
- A Recently Evolved Sublineage of the Mycobacterium tuberculosis Beijing Strain Family Is Associated with an Increased Ability to Spread and Cause DiseaseJournal of Clinical Microbiology, 2007
- Beijing and Haarlem Genotypes Are Overrepresented among Children with Drug-Resistant Tuberculosis in the Western Cape Province of South AfricaJournal of Clinical Microbiology, 2006
- The emergence of Beijing family genotypes ofMycobacterium tuberculosisand low-level protection by bacille Calmette–Guérin (BCG) vaccines: is there a link?Clinical and Experimental Immunology, 2006
- Impact of Bacterial Genetics on the Transmission of Isoniazid-Resistant Mycobacterium tuberculosisPLoS Pathogens, 2006
- Impact of drug resistance on fitness of Mycobacterium tuberculosis strains of the W-Beijing genotypeFEMS Immunology & Medical Microbiology, 2004
- Mycobacterium tuberculosis Beijing Genotype Emerging in VietnamEmerging Infectious Diseases, 2000