Comparison of nonstructural protein-1 antigen detection by rapid and enzyme-linked immunosorbent assay test and its correlation with polymerase chain reaction for early diagnosis of dengue

INTRODUCTION: Early diagnosis of dengue is important for appropriate clinical management and vector control. Different serological tests based on the principle of immunochromatography and enzyme-linked immunosorbent assay (ELISA) are commonly used for detection of antigen and antibodies of dengue virus. The performance of these tests depends on the sensitivity and specificity. Hence, the study was undertaken to compare nonstructural protein-1 (NS1) antigen detection by rapid and ELISA with real-time polymerase chain reaction (RT-PCR) for diagnosis of dengue. MATERIALS AND METHODS: Prospective laboratory study was carried out on sera samples (n = 200) from clinically suspected cases of dengue. The sera samples were subjected for NS1 antigen detection test by rapid test, NS1 ELISA, and RT-PCR. The results of rapid and ELISA tests were compared with real Time PCR. RESULTS: The sensitivity, specificity, positive, and negative predictive value of rapid dengue NS1 antigen test were 81.5%, 66.7%, 78.2%, and 71.1%, respectively whereas that of NS1 ELISA were 89.9%, 100%, 100%, and 94%, respectively. Concordance of Rapid NS1 and NS1 ELISA with PCR was 75.5% and 94%. DISCUSSION AND CONCLUSION: NS1 antigen ELISA can be implemented in diagnostic laboratories for diagnosis of dengue in the acute phase of illness. The test also has great potential value for use in epidemic situations, as it could facilitate the early screening of patients and limit disease expansion

Concurrent evaluation of microscopic observation of drug susceptibility assay for pulmonary and extrapulmonary tuberculosis

BACKGROUND: Methods for detection and drug susceptibility of tuberculosis (TB) with solid media are inexpensive but slow and laborious. Rapid methods to diagnose TB and multidrug-resistant TB (MDR-TB) are a global priority for TB control. OBJECTIVES: A study was performed to compare the sensitivity of detection of mycobacterial growth and time of culture positivity by microscopic observation of drug susceptibility (MODS) assay with that of Lowenstein–Jensen (LJ) culture in pulmonary and extrapulmonary TB and to evaluate the concordance of the susceptibilities to isoniazid (INH) and rifampicin (RIF) by MODS and proportion method on LJ. MATERIALS AND METHODS: A prospective, laboratory-based study was conducted on a total of 300 samples from suspected cases of pulmonary and extrapulmonary TB. Samples were inoculated on LJ medium as per the standard guidelines and MODS assay was performed. RESULTS: Sensitivity of MODS assay was 80% and 83.3% and specificity was 92.9% and 83.3% for pulmonary and extrapulmonary samples, respectively. Difference between mean time to detection of Mycobacterium TB (MTB) by LJ medium and MODS was statistically significant, with MODS being faster. drug susceptibility testing (DST) by MODS when compared to economic variant of proportion method was 87.87% for RIF, 90.9% for INH, and 96.96% for MDR-TB detection. CONCLUSIONS: MODS assay provides rapid, safe, and sensitive detection of TB faster than the existing gold standard. It is extremely promising in effectively diagnosing MDR-TB

Antifungal susceptibility of Candida by disc diffusion method of isolates from clinical cases of vulvovaginitis of a tertiary care hospital in Mumbai

Background: Vulvovaginal Candidiasis (VVC) is a grave public health problem affecting young and middle-aged females especially during their reproductive life. Though Candida albicans is the commonest species involved, recurrent episodes of VVC are caused by non-albicans Candida (NAC) spp. The NAC spp also show resistance to commonly used antifungal drugs leading to recurrent infections, complications and treatment failure. In addition, widespread use and over the counter availability of antifungals leads to resistance. Therefore, antifungal susceptibility testing of Candida isolates is mandatory for selection of an appropriate and accurate antifungal therapeutic agent Objectives: To perform in vitro antifungal susceptibility testing by disc diffusion method. Materials and Methods: A total of 150 vaginal Candida isolates were used to perform Antifungal susceptibility test by disc diffusion method. Mueller Hinton Agar with 2% Glucose and 0.5 μg/mL Methylene Blue Dye medium and six antifungal drugs Amphotericin B, Fluconazole, Itraconazole, Ketoconazole, Clotrimazole and Nystatin were used. Results were calculated using CLSI M 44-A2 (S3) for fluconazole and standard reference articles for other drugs. Results and Conclusion: Susceptibility of Candida albicans was 100% to Amphotericin B, Nystatin and 97.2% to Ketoconazole. NAC spp were less susceptible to Fluconazole and Clotrimazole as compared to Candida albicans. Resistance was found even to Amphotericin B and Nystatin among NAC spp. Accurate and reliable antifungal susceptibility testing is necessary to help the clinicians in better patient management and preventing the emerging antifungal resistance