Sputum culture contamination and associated characteristics in a diagnostic clinical trial, Papua New Guinea

SETTING: Papua New Guinea is a high-burden multidrug-resistant TB (MDR/RR-TB) country that reports low rates of bacteriological confirmation. Sputum drug susceptibility testing for second-line drugs is important. Access to culture is limited. OBJECTIVE: To evaluate the prevalence of mycobacterial sp...

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Bibliographic Details
Main Authors: ND. Tenakanai, J.K. Banamu, Y. Lin, D. Walsh, R. Simbil, M. Globan, A. Penn-Nicholson, P. du Cros, J. Greig
Format: Article
Language:English
Published: The Union 2024-12-01
Series:Public Health Action
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Online Access:https://www.ingentaconnect.com/contentone/iuatld/pha/2024/00000014/00000004/art00004
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Summary:SETTING: Papua New Guinea is a high-burden multidrug-resistant TB (MDR/RR-TB) country that reports low rates of bacteriological confirmation. Sputum drug susceptibility testing for second-line drugs is important. Access to culture is limited. OBJECTIVE: To evaluate the prevalence of mycobacterial sputum sample culture contamination and determine factors associated with contamination. DESIGN: A retrospective analysis of data from a TB diagnostic accuracy study that used culture as the diagnostic reference standard. Data included characteristics of people with presumptive pulmonary TB who provided sputum, sputum quality and culture results. RESULTS: Sputum (1–3 samples) was collected from 174 adults. The median age was 33 years (IQR 24–47). Of 337 samples sent for culture, 28% were contaminated. Contamination was strongly associated with samples self-collected by participants outside clinic hours (aOR 5.69; 95% CI 2.62–12.38). Contamination risk increased with delays in shipping to the reference laboratory (aOR 1.19 per day, 95% CI 1.10–1.29) beyond the minimum 3 days. Contamination was less frequent among people aged 35–44 years compared to 18–24 years (aOR 0.27, 95% CI 0.10–0.73). Sputum quality was not associated with culture contamination. CONCLUSION: Culture contamination could be reduced using spot sputum collection, expedited submission to laboratories and faster shipping when required.
ISSN:2220-8372