Castellanos María Eugenia, Lau-Bonilla Dalia, Moller Anneliese, Arathoon Eduardo, Samayoa Blanca, Quinn Frederick D, Ebell Mark H, Dobbin Kevin K, Whalen Christopher C
Global Health Institute, College of Public Health, University of Georgia, Athens, Georgia.
Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, Georgia.
Am J Trop Med Hyg. 2022 Feb 28;106(4):1173-1181. doi: 10.4269/ajtmh.20-0742. Print 2022 Apr 6.
There is little information about the amount of recent tuberculosis transmission in low-income settings. Genetic clustering can help identify ongoing transmission events. A retrospective observational study was performed on Mycobacterium tuberculosis isolates from persons living with HIV (PLHIV) and HIV-seronegative participants who submitted samples to a referral tuberculosis laboratory in Guatemala City, Guatemala from 2010 to 2014. Genotyping results were classified according to the international spoligotyping database, SITVIT2. Spoligotype patterns were categorized as clustered or nonclustered depending on their genotype. The proportion of clustering and the index of recent transmission index (RTIn-1) were estimated. In the RTIn-1 method, clustered cases represent recent transmission, whereas nonclustered cases represent reactivation of older tuberculosis infections. As a secondary aim, the potential risk factors associated with clustering in isolates from the subset of participants living with HIV were explored. From 2010 to 2014, a total of 479 study participants were confirmed as culture-positive tuberculosis cases. Among the 400 available isolates, 71 spoligotype patterns were identified. Overall, the most frequent spoligotyping families were Latin American-Mediterranean (LAM) (39%), followed by T (22%) and Haarlem (14%). Out of the 400 isolates, 365 were grouped in 36 clusters (range of cluster size: 2-92). Thus, the proportion of clustering was 91% and the RTIn-1 was 82%. Among PLHIV, pulmonary tuberculosis was associated with clustering (OR = 4.3, 95% CI 1.0-17.7). Our findings suggest high levels of ongoing transmission of M. tuberculosis in Guatemala as revealed by the high proportion of isolates falling into genomic clusters.
关于低收入环境中近期结核病传播量的信息很少。基因聚类有助于识别正在发生的传播事件。对2010年至2014年期间向危地马拉城一家转诊结核病实验室提交样本的艾滋病毒感染者（PLHIV）和艾滋病毒血清阴性参与者的结核分枝杆菌分离株进行了一项回顾性观察研究。基因分型结果根据国际间隔寡核苷酸分型数据库SITVIT2进行分类。根据其基因型，间隔寡核苷酸分型模式分为聚集型或非聚集型。估计了聚集比例和近期传播指数（RTIn-1）。在RTIn-1方法中，聚集病例代表近期传播，而非聚集病例代表旧结核感染的重新激活。作为次要目标，探讨了与艾滋病毒感染者子集中分离株聚集相关的潜在危险因素。2010年至2014年期间，共有479名研究参与者被确认为培养阳性结核病病例。在400株可用分离株中，鉴定出71种间隔寡核苷酸分型模式。总体而言，最常见的间隔寡核苷酸分型家族是拉丁美洲-地中海型（LAM）（39%），其次是T型（22%）和哈勒姆型（14%）。在400株分离株中，365株被分为36个簇（簇大小范围：2-92）。因此，聚集比例为91%，RTIn-1为82%。在艾滋病毒感染者中，肺结核与聚集相关（比值比=4.3，95%可信区间1.0-17.7）。我们的研究结果表明，危地马拉结核分枝杆菌的持续传播水平很高，这从落入基因组簇的分离株比例很高可以看出。
