Molecular epidemiology approach to tackle treatment failure in drug resistant tuberculosis (dr-tb)

Abstract

The aim: To analyze molecular epidemiology features of M. tuberculosis in Kyiv oblast; and to identify the safest mode of TB treatment, which will allow clinicians to minimize the risk of drug-resistant strains nosocomial transmission. Materials and methods: 55 isolates of M. tuberculosis were collected in January-April, 2018 from 31 patients with new cases and 24 patients with re-treatment cases of sputum culture-positive pulmonary TB, in Kyiv oblast, Ukraine. DNA samples extracted from all the isolates were used for 15-loci MIRU-VNTR molecular typing with further M. tuberculosis strains comparison by means of MIRU-VNTRplus web tool (http://www.miru-vntrplus.org). Results: Phylogenetic tree that reflects strains interrelationship reveals four main clusters, the largest of which spans 34 isolates. The presence of two big subclusters with 10 and 7 identical genotypes inside the largest cluster strongly suggests their tight epidemiologic relationship. Smaller clusters consist of five (Harlem), three (URAL), and two unidentified isolates. 10 singletons were detected, among which LAM, URAL and Cameroon lineages were identified; in these cases, epidemiological connection was presumably ruled out. Conclusions: High clustering level of isolates of M. tuberculosis suggests possible contact between patients from whom these isolates were obtained. Predominance of Beijing family in the clusters is associated with high DR-TB level, at least in eastern European countries. Similarity of the clusters isolated from different patients in a household or a hospital suggests high probability of recent disease transmission. Clustering genotypes from households and hospital wards can be a surrogate criterion of infection control effectiveness.