Molecular Characterization of katG and inhA Mutations by Genotype MTBDRplus Line Probe Assay To Guide Isoniazid and Ethionamide Use for Drug-Resistant Tuberculosis.

Introduction Drug-resistant tuberculosis (TB) continues to be a global health threat in all its forms. Significant resistance has been observed against isoniazid (INH), one of the most important therapeutic options for treating TB. Molecular testing methods such as line probe assay (LPA) provide rapid diagnosis and early management. Mutations in different genes can be detected, which indicate INH and ethionamide (ETH) drug resistance. We aimed to determine the frequency of these mutations in katG and inhA genes by LPA to guide INH and ETH use for drug-resistant TB. Materials and methods Two consecutive sputum samples were collected from each patient, followed by decontamination by N­acetyl­L­cysteine and sodium hydroxide method. LPA was performed on the decontaminated samples by GenoType MTBDRplus, and the strips were analyzed. Results Out of the 3,398 smear-positive samples tested by LPA, valid results were found in 3,085 (90.79%) samples. Of the 3,085 samples, INH resistance was seen in 295 samples (9.56%), of which mono INH resistance was in 204 samples, and 91 were multidrug resistant. katG S315T was the most common mutation responsible for high-level INH resistance. At the same time, inhA c15t was the most common mutation associated with low-level INH resistance and ETH cross-resistance. The average turnaround time for the processing and reporting of samples was five days. Conclusions The high burden of INH resistance is alarming and can be a major obstacle to TB elimination. Although molecular methods have reduced the reporting time leading to early management of the patients still, a large knowledge gap persists.

Ventilator-associated pneumonia in a tertiary care intensive care unit: Analysis of incidence, risk factors and mortality.

BACKGROUND: Ventilator-associated pneumonia (VAP) is the most common nosocomial infection diagnosed in the intensive care unit (ICU) and in spite of advances in diagnostic techniques and management it remains a common cause of hospital morbidity and mortality. OBJECTIVE: The primary objective of the following study is to determine the incidence, various risk factors and attributable mortality associated with VAP and secondary objective is to identify the various bacterial pathogens causing VAP in the ICU. MATERIALS AND METHODS: This prospective observational study was carried out over a period of 1 year. VAP was diagnosed using the clinical pulmonary infection score. Endotracheal aspirate (ETA) and bronchoalveolar lavage (BAL) samples of suspected cases of VAP were collected from ICU patients and processed as per standard protocols. STATISTICAL ANALYSIS: Fisher's exact test was applied when to compare two or more set of variables were compared. RESULTS: The incidence of VAP in our study was 57.14% and the incidence density of VAP was 31.7/1000 ventilator days. Trauma was the commonest underlying condition associated with VAP. The incidence of VAP increased as the duration of mechanical ventilation increased and there was a total agreement in bacteriology between semi-quantitative ETAs and BALs in our study. The overall mortality associated with VAP was observed to be 48.33%. CONCLUSIONS: The incidence of VAP was 57.14%. Study showed that the incidence of VAP is directly proportional to the duration of mechanical ventilation. The most common pathogens causing VAP were Acinetobacter spp. and Pseudomonas aeruginosa and were associated with a high fatality rate.