Trends in rifampicin and isoniazid resistance in patients with presumptive TB.

BACKGROUND: Early diagnosis of drug-resistant TB (DR-TB) is crucial in preventing the spread of the disease in the community. Introduction of upfront decentralised drug susceptibility testing to district-level as part of universal drug susceptibility testing (UDST) policy increased the feasibility of rapid and early testing for drug resistance closer to the patient and has resulted in reduced circumstances for transmission. The introduction of the first-line line-probe assay (FL-LPA), GenoType® MTBDRplus v2, has had an extensive impact on the management of multidrug-resistant TB (MDR-TB) in India.MATERIALS and METHODS: Sputum samples of patients with presumptive TB and DR-TB from selected districts of Tamil Nadu received through National TB Elimination Programme (NTEP) were subjected to FL-LPA as per programme guidelines. In this study, we present trends in genotypic resistance to isoniazid (INH) and rifampicin (RIF) during the 4 years (2016-2019) among these patients. Band patterns were analysed as per the updated GLI (Global Laboratory Initiative) LPA interpretation and reporting guidelines.RESULTS: A total of 26,349 samples were received during the study period. Smear-positive samples (n = 20231) were directly subjected to FL-LPA; smear-negative samples were cultured in liquid media and M. tuberculosis-positive cultures were tested using FL-LPA. A total of 18,441 were MTB-positive on FL-LPA. INH monoresistance, RIF monoresistance and MDR-TB was observed in respectively 8.7%, 1.1% and 3.3% of the samples. There was a decreasing trend in all types of resistance observed particularly after 2017 (P < 0.001). MDR-TB showed a steady decrease from 5.6% to 1.8%. S531L (19.5%) and S315T (61.1%) were the most common mutations identified in the rpoB and katG genes, respectively. The percentage of inhA-c-15t promoter mutation, indicating low-level INH resistance, showed a consistent increase (P < 0.001).CONCLUSION: The impact of the UDST policy on the NTEP may have led to this decreasing trend in RIF and INH resistance observed in the study period. The increase in low-level INH resistance mutation inhA-c-15t may be associated with ethionamide/prothionamide resistance, and this should be taken into account when designing DR-TB regimen.

Age- and sex-related mandibular dimensional changes: A radiomorphometric analysis on panoramic radiographs.

INTRODUCTION: Mandible undergoes age- and sex-related structural changes similar to other bones of the body. Thus, morphometric analysis of the mandible helps in age and sex determination. AIM: To investigate the influence of age and sex on the mandible by measuring three parameters, i.e. gonial angle, ramus height and bigonial width. MATERIALS AND METHODS: A retrospective radiomorphometric analysis was conducted in the department of Oral Medicine and Radiology. A total of 300 panoramic radiographs (150 males and 150 females) equally distributed in six study groups according to the age were analysed. The measurements were performed using DIGORA 2.8 software for Windows. The acquired data was statistically analysed by one way ANOVA test and Student's t-test using SPSS (v. 19.0). RESULTS: Statistically significant differences according to age were found in gonial angle dimensions. Ramus height and bigonial width did not demonstrate statistically significant co-relation with age. According to sex, all the three study parameters showed statistically highly significant differences. CONCLUSION: The morphometric analysis of the mandible is a useful tool for age estimation and sex determination.