Risk factors of tuberculosis in Mizoram: First report of the possible role of water source.

BACKGROUND: Various risk factors of tuberculosis have been studied across the globe, but these may be altered over time and can be specific to geographical regions and there is not much information available from Northeastern region of India. This study aims to investigate the various risk factors of tuberculosis and analyze the presence of any less-established risk factors. METHODS: A total of 400 TB cases and 840 healthy controls were interviewed from December 2017 - June 2020. Logistic regression model was used to analyze associated risk factors. Patients were categorized into pulmonary and extrapulmonary TB. RESULTS: Clinical presentation such as fever, cough, weight loss, chest pain and night sweats were more prominent among pulmonary TB patients. The most common mode of diagnosis among pulmonary and extrapulmonary TB were GeneXpert and X-ray, respectively. Tuberculosis was found to be strongly prevalent among patients from lower socio-economic status, less educated, unemployed and improper housing condition. Other risk factors associated were alcohol consumption, neighbours with TB, travel history, no BCG vaccine, mass gathering, and non-ideal weight. An interesting less-established risk factor that demands attention is the source of water supply (p-0.017, OR-2.313, CI: 1.160-4.613), which was significant in this study. CONCLUSION: Our data suggests that apart from all the well-established risk factors for TB, water supply might play a crucial role towards the transmission of TB, since proper hospital waste water treatment is yet to be adopted in Mizoram, Northeast India. From a public health standpoint, this highlights the need for further research in this area.

Distribution and frequency of common mutations in rpoB gene of Mycobacterium tuberculosis detected by Xpert MTB/RIF and identification of residential areas of rifampicin resistant-TB cases: A first retrospective study from Mizoram, Northeast India.

Background: Rifampicin resistance (RR) is a surrogate marker of multidrug-resistant tuberculosis. The aim of this study is to determine the frequency of the commonly mutated probes for rpoB gene and locate the residential areas of the Rifampicin Resistant-TB (RR-TB) patients in a high endemic zone of Northeast India. Methods: Archived data of 13,454 Xpert MTB/RIF reports were evaluated retrospectively between 2014 and 2021. Socio-demographic and available clinical information were reviewed and analyzed for RR-TB cases only. Logistic Regression was used to analyze the parameters with respect to probe types. P-value ≤ 0.05 was considered to be statistically significant. Results: 2,894 patients had Mycobacterium tuberculosis infection out of which 460 were RR-TB, which was most prevalent among 25-34 years. The most common mutation occurred in probe A (25.9 %) followed by E (23.5 %), D (9.8 %), B (2.6 %) and the least in C (0.2 %). High prevalence (34.3 %) of probe mutation combinations were also found: probes AB (0.4 %), AD (32.8 %), AE (0.4 %), DE (0.2 %) and ADE (0.4 %). Seventeen patients (3.7 %) were found without any missing probes. RR-TB patients were mostly located in Aizawl North -III, South -II and East -II constituencies. Conclusion: This study provides genetic pattern of drug resistance accountable for RR over the past years in Mizoram which will help local clinicians in the initiation of correct treatment. Also, our findings provide a baseline data on the magnitude of RR-TB within the state and identification of the residential areas can help local health authorities in planning surveillance programs to control the spread of RR-TB.

MGIT sensitivity testing and genotyping of drug resistant Mycobacterium tuberculosis isolates from Mizoram, Northeast India.

PURPOSE: Tuberculosis, a crucial infectious disease is still a health concern globally. India is among the countries with high MDR-TB burden. Currently, sputum smear microscopy using Ziehl Neelsen stain and GeneXpert are the only diagnostic means in Mizoram. This study was done to characterize local tuberculosis strains circulating in Mizoram. METHODS: Sputum was cultured using MGIT 960 and DST was performed for Streptomycin, Isoniazid, Rifampicin, Ethambutol and Pyrazinamide. GeneXpert test was done simultaneously. DNA was extracted using Trueprep AUTO v2, molbio diagnostics. Antibiotic Resistance Genes and LSP were amplified and sequenced. RESULTS: Ser315Thr was the most common mutation in katG among MDR-TB isolates. GeneXpert probes A and D drop out upon sequencing showed L511P, H526Q and H526L mutation. The L511P and H526Q mutations were seen in new and treated cases. Discrepancy between MGIT 960 and GeneXpert were observed. LSP-PCR revealed that Indo-Oceanic, East-African Indian, Euro-American and Beijing lineages were found in Mizoram. CONCLUSION: This study provides mutation information on the resistant genotypes detected with GeneXpert as well as MGIT 960. It also provides information on the lineages of Mycobacterium tuberculosis circulating in the state. Utilization of sequencing technologies is essential in diagnostic laboratories to rule out discrepant results and as a cautionary measure to prevent wrong diagnosis and treatment.