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The infectiousness of tuberculosis patients coinfected with HIV.

Escombe, AR; Moore, DAJ; Gilman, RH; Pan, W; Navincopa, M; Ticona, E; Martínez, C; Caviedes, L; Sheen, P; Gonzalez, A; et al. Escombe, AR; Moore, DAJ; Gilman, RH; Pan, W; Navincopa, M; Ticona, E; Martínez, C; Caviedes, L; Sheen, P; Gonzalez, A; Noakes, CJ; Friedland, JS; Evans, CA (2008) The infectiousness of tuberculosis patients coinfected with HIV. PLoS Med, 5 (9). e188. ISSN 1549-1676
SGUL Authors: Friedland, Jonathan Samuel

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BACKGROUND: The current understanding of airborne tuberculosis (TB) transmission is based on classic 1950s studies in which guinea pigs were exposed to air from a tuberculosis ward. Recently we recreated this model in Lima, Perú, and in this paper we report the use of molecular fingerprinting to investigate patient infectiousness in the current era of HIV infection and multidrug-resistant (MDR) TB. METHODS AND FINDINGS: All air from a mechanically ventilated negative-pressure HIV-TB ward was exhausted over guinea pigs housed in an airborne transmission study facility on the roof. Animals had monthly tuberculin skin tests, and positive reactors were removed for autopsy and organ culture for M. tuberculosis. Temporal exposure patterns, drug susceptibility testing, and DNA fingerprinting of patient and animal TB strains defined infectious TB patients. Relative patient infectiousness was calculated using the Wells-Riley model of airborne infection. Over 505 study days there were 118 ward admissions of 97 HIV-positive pulmonary TB patients. Of 292 exposed guinea pigs, 144 had evidence of TB disease; a further 30 were tuberculin skin test positive only. There was marked variability in patient infectiousness; only 8.5% of 118 ward admissions by TB patients were shown by DNA fingerprinting to have caused 98% of the 125 characterised cases of secondary animal TB. 90% of TB transmission occurred from inadequately treated MDR TB patients. Three highly infectious MDR TB patients produced 226, 52, and 40 airborne infectious units (quanta) per hour. CONCLUSIONS: A small number of inadequately treated MDR TB patients coinfected with HIV were responsible for almost all TB transmission, and some patients were highly infectious. This result highlights the importance of rapid TB drug-susceptibility testing to allow prompt initiation of effective treatment, and environmental control measures to reduce ongoing TB transmission in crowded health care settings. TB infection control must be prioritized in order to prevent health care facilities from disseminating the drug-resistant TB that they are attempting to treat.

Item Type: Article
Additional Information: © 2008 Escombe et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Keywords: Adult, Animals, Female, Guinea Pigs, HIV Infections, Humans, Male, Sputum, Tuberculosis, Sputum, Animals, Humans, Guinea Pigs, Tuberculosis, HIV Infections, Adult, Female, Male, Science & Technology, Life Sciences & Biomedicine, Medicine, General & Internal, General & Internal Medicine, DRUG-RESISTANT TUBERCULOSIS, MYCOBACTERIUM-TUBERCULOSIS, PULMONARY TUBERCULOSIS, AIRBORNE TRANSMISSION, MULTIDRUG-RESISTANT, CONTACTS, SPUTUM, CHEMOTHERAPY, BACILLI, AIR, 11 Medical And Health Sciences, General & Internal Medicine
Journal or Publication Title: PLoS Med
ISSN: 1549-1676
Language: eng
16 September 2008Published
7 July 2008Accepted
Publisher License: Creative Commons: Attribution 4.0
Project IDFunderFunder ID
PubMed ID: 18798687
Web of Science ID: WOS:000260442300014
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