CHARACTERIZATION OF THE PROPORTION OF CLUSTERED TUBERCULOSIS CASES IN GUATEMALA, CA: INSIGHTS FROM A MOLECULAR EPIDEMIOLOGY STUDY, 2010-2014.

Background. There is little information about the proportion of clustering of tuberculosis cases from low-income settings, which can represent ongoing transmission events. Objectives. We investigated the proportion of clustered tuberculosis cases based on genotypic matching in Guatemala and potential factors associated with clustering in HIV-infected subjects. Moreover, the genetic diversity of Mycobacterium tuberculosis isolates in this country is presented. Methods. We performed an observational study on M. tuberculosis isolates from tuberculosis cases that submitted samples to a referral laboratory in Guatemala City, Guatemala (2010-2014). Genotyping results were classified according to the international spoligotyping database. We estimated the proportion of clustering and the recent transmission index (RTIn-1). We analyzed the association between clinical and behavioral variables and clustering in the HIV-population. Findings. Spoligotype patterns were available from 391 patients out of 479 confirmed cases (82%). The most frequent spoligotyping families were LAM (39%), T (22%) and Haarlem (14%). The proportion of clustering was 91% and the RTIn-1 was 82%. Clustered isolates grouped in 36 clusters (range: 2-92). Pulmonary tuberculosis was associated with clustering in the HIV-infected group (OR=4.3, 95% CI 1.0-17.7). Conclusion. There might be high levels of ongoing transmission of M. tuberculosis in Guatemala as indicated by clustering in a convenience sample.