Relapse, re-infection and mixed infections in tuberculosis disease.
Tuberculosis (TB) disease can be characterized by genotypic and phenotypic complexity in Mycobacterium tuberculosis bacilli within a single patient. This microbiological heterogeneity has become an area of intense study due its perceived importance in drug tolerance, drug resistance and as a surrogate measure of transmission rates. This review presents a descriptive analysis of research describing the prevalence of mixed-strain TB infections in geographically distinct locations. Despite significant variation in disease burden and a rampant human immunodeficiency virus (HIV)-TB co-epidemic, there was no difference in the prevalence range of mixed infections reported in African countries when compared to the rest of the world. The occurrence of recurrent TB was associated with a higher prevalence of mixed-strain infections, but this difference was not reported as statistically significant. These interpretations were limited by differences in the design and overall size of the studies assessed. Factors such as sputum quality, culture media, number of repeated culture steps, molecular typing methods and HIV-infection status can affect the detection of mixed-strain infection. It is recommended that future clinical studies should focus on settings with varying TB burdens, with a common sample processing protocol to gain further insight into these phenomena and develop novel transmission blocking strategies.
DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg 2000, South Africa.
Amanda
A
McIvor
Centre for Tuberculosis, National Institute for Communicable Diseases and National Health Laboratory Service, Johannesburg, 2000, South Africa.
Hendrik
H
Koornhof
DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg 2000, South Africa.|CAPRISA, Centre for the AIDS Programme of Research in South Africa, Durban, 4001, South Africa.
Bavesh Davandra
BD
Kana
D000995:Antitubercular Agents / Q000494:pharmacology / Q000627:therapeutic use; D015373:Bacterial Typing Techniques; D060085:Coinfection; D024881:Drug Resistance, Bacterial; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000187:drug effects / Q000235:genetics; D015995:Prevalence; D012008:Recurrence; D012189:Retrospective Studies; D014376:Tuberculosis / Q000188:drug therapy / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology*
D000995:Antitubercular Agents
heteroresistance; mixed infections; re-infection; recurrent disease; relapse; tuberculosis