QuantiFERON-TB Gold plus testing for the detection of LTBI among health care workers in major TB hospitals of the Northern Kyrgyz Republic.

BACKGROUND: Health care workers (HCW) are at increased risk of TB infection due to their close contact with infected patients with active TB. The objectives of the study were (1) to assess the prevalence of LTBI among HCW in the Northern Kyrgyz Republic, and (2) to determine the association of LTBI with job positions or departments. METHODS: HCWs from four TB hospitals in the Northern Kyrgyz Republic were tested with the interferon-gamma release assay (IGRA) Quantiferon-TB Gold plus (QFT) for the detection of an immune response to TB as marker of TB infection. Age was controlled for as a confounder. Univariate and multivariable analysis were performed using logistic regression to assess the association of the risk factors (job position, and department) with having a QTF positive result. Firth's penalized-likelihood estimates were used to account for the small-sample size. Pairwise comparisons using the Bonferroni correction (conservative) and comparisons without adjusting for multiple comparisons (unadjusted) were used to identify the categories where differences occurred. RESULTS: QFT yielded valid results for 404 HCW, with 189 (46.7%) having a positive test. In the National Tuberculosis Center there was an increased odds to have a positive QFT test for the position of physician (OR = 8.7, 95%, CI = 1.2-60.5, p = 0.03) and laboratory staff (OR = 19.8, 95% CI = 2.9-135.4, p < 0.01) when administration staff was used as the baseline. When comparing departments for all hospitals combined, laboratories (OR 7.65; 95%CI 2.3-24.9; p < 0.001), smear negative TB (OR 5.90; 95%CI 1.6-21.8; p = 0.008), surgery (OR 3.79; 95%CI 1.3-11.4; p = 0.018), and outpatient clinics (OR 3.80; 95%CI 1.1-13.0; p = 0.03) had higher odds of a positive QFT result than the admin department. Fifteen of the 49 HCW with follow-up tests converted from negative to positive at follow-up testing. CONCLUSIONS: This is the first report on prevalence and risk factors of LTBI for HCW in the Kyrgyz republic, and results indicate there may be an increased risk for LTBI among physicians and laboratory personnel. Further research should investigate gaps of infection control measures particularly for physicians and laboratory staff and lead to further improvement of policies.

Implementation of whole genome sequencing for tuberculosis diagnostics in a low-middle income, high MDR-TB burden country.

Whole genome sequencing (WGS) is revolutionary for diagnostics of TB and its mutations associated with drug-resistances, but its uptake in low- and middle-income countries is hindered by concerns of implementation feasibility. Here, we provide a proof of concept for its successful implementation in such a setting. WGS was implemented in the Kyrgyz Republic. We estimated needs of up to 55 TB-WGS per week and chose the MiSeq platform (Illumina, USA) because of its capacity of up to 60 TB-WGS per week. The project's timeline was completed in 93-weeks. Costs of large equipment and accompanying costs were 222,065 USD and 8462 USD, respectively. The first 174 WGS costed 277 USD per sequence, but this was skewed by training inefficiencies. Based on real prices and presuming optimal utilization of WGS capacities, WGS costs could drop to 167 and 141 USD per WGS using MiSeq Reagent Kits v2 (500-cycles) and v3 (600-cycles), respectively. Five trainings were required to prepare the staff for autonomous WGS which cost 48,250 USD. External assessment confirmed excellent performance of WGS by the Kyrgyz laboratory in an interlaboratory comparison of 30 M. tuberculosis genomes showing complete agreeance of results.

Implementing contact tracing for tuberculosis in Kyrgyz Republic and risk factors for positivity using QuantiFERON-TB Gold plus.

BACKGROUND: Effective active case finding (ACF) activities are essential for early identification of new cases of active tuberculosis (TB) and latent TB infection (LTBI). Accurate diagnostics as well as the ability to identify contacts at high risk of infection are essential for ACF, and have not been systematically reported from Central Asia. The objective was to implement a pilot ACF program to determine the prevalence and risk factors for LTBI and active TB among contacts of individuals with TB in Kyrgyz Republic using Quantiferon-TB Gold plus (QuantiFERON). METHODS: An enhanced ACF project in the Kyrgyz Republic was implemented in which close and household (home) contacts of TB patients from the Issyk-Kul Oblast TB Center were visited at home. QuantiFERON and the tuberculin skin test (TST) alongside clinical and bacteriological examination were used to identify LTBI and active TB cases among contacts. The association for QuantiFERON positivity and risk factors were analysed and compared to TST results. RESULTS: Implementation of ACF with QuantiFERON involved close collaboration with the national sanitary and epidemiological services (SES) and laboratories in the Kyrgyz Republic. From 67 index cases, 296 contacts were enrolled of whom 253 had QuantiFERON or TST results; of those 103 contacts had LTBI (positive TST or IGRA), and four (1.4%) active TB cases were detected. Index case smear microscopy (OR 1.76) and high household density (OR 1.97) were significant risk factors for QuantiFERON positivity for all contacts. When stratified by age, association with smear positivity disappeared for children below 15 years. TST was not associated with any risk factor. CONCLUSIONS: This is the first time that ACF activities have been reported for Central Asia, and provide insight for implementation of effective ACF in the region. These ACF activities using QuantiFERON led to increase in the detection of LTBI and active cases, prior to patients seeking treatment. Household density should be taken into consideration as an important risk factor for the stratification of future ACF activities.