Tenakanai N D, Banamu J K, Lin Y, Walsh D, Simbil R, Globan M, Penn-Nicholson A, du Cros P, Greig J
Burnet Institute, Melbourne, Australia.
Central Public Health Laboratory, PNG National Department of Health (NDoH), Port Moresby, PNG.
Public Health Action. 2024 Dec 1;14(4):152-157. doi: 10.5588/pha.24.0029. eCollection 2024 Dec.
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.
To evaluate the prevalence of mycobacterial sputum sample culture contamination and determine factors associated with contamination.
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.
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.
Culture contamination could be reduced using spot sputum collection, expedited submission to laboratories and faster shipping when required.
巴布亚新几内亚是一个耐多药结核病（MDR/RR-TB）高负担国家，细菌学确诊率较低。二线药物的痰药敏试验很重要。获得培养的机会有限。
评估分枝杆菌痰标本培养污染的患病率，并确定与污染相关的因素。
对一项以培养作为诊断参考标准的结核病诊断准确性研究的数据进行回顾性分析。数据包括疑似肺结核患者的特征、痰液质量和培养结果。
从174名成年人中收集了痰液（1-3份样本）。中位年龄为33岁（四分位间距24-47岁）。在送去培养的337份样本中，28%被污染。污染与参与者在门诊时间以外自行采集的样本密切相关（调整后比值比5.69；95%置信区间2.62-12.38）。超过最短3天运送到参考实验室的延迟会增加污染风险（每天调整后比值比1.19，95%置信区间1.10-1.29）。与18-24岁人群相比，35-44岁人群的污染频率较低（调整后比值比0.27，95%置信区间0.10-0.73）。痰液质量与培养污染无关。
使用即时痰标本采集、加快提交给实验室以及在需要时更快运输等方法，可以减少培养污染。
