Evaluation of diagnostic accuracy of loop-mediated isothermal amplification method (LAMP) compared with polymerase chain reaction (PCR) for Leptospira spp. in clinical samples: a systematic review and meta-analysis

Loop-mediated isothermal amplification (LAMP) test is widely used in molecular diagnostics as a point-of-care technique alternative to traditional PCR especially in resource-limited countries. LAMP has been recently used to diagnose leptospirosis. Therefore, we undertook a systematic review and meta-analysis to compare the accuracy of LAMP with PCR in the diagnosis of leptospirosis. Sixty-one studies were extracted from three international databases and analyzed throughout using the PRISMA guideline. The pooled sensitivity of LAMP and PCR technique was 0.80 (95% CI: 0.58–0.90) and 0.54 (95% CI: 0.35–0.67) respectively indicating that LAMP is more sensitive than PCR. The Q* value of LAMP and PCR-based technique is 274.61 and 397.95, respectively. Among the analyzed studies, significant heterogeneity was observed where I2 is 90.90% for LAMP-based and 86.18% for PCR-based. Our study suggests that LAMP has better diagnostic accuracy than PCR. However, future work should be carried out to reduce heterogeneity as well as to improve and develop effective intervention strategies

Effect of nicotine on the adherence and gene expression of selected oral microorganisms / Shan Gunasegar

The ability of microbes to adhere on tooth surfaces coated with salivary pellicle lead to the formation of biofilm. Some environment risk factor such as smoking, poor oral hygiene and diet can contribute to the formation of plaque on tooth surface. The aim of this study was to investigate the effect of nicotine on the antimicrobial, adherence capacity, expression of adherence-associated genes and extracellular polysaccharide (EPS) and micro-colonies formation of selected oral microorganisms; Streptococcus sanguinis, Streptococcus mutans, Candida albicans and Candida parapsilosis. Growth profiles were carried out to determine the survival rate of the selected oral microbes in different concentration of nicotine (1, 2, 4 and 8 mg/ml). The relative number of viable microbial cells was estimated using viable plate count enumeration method and biofilm growth was quantified using crystal violet assay. Cell surface hydrophobicity and the cell aggregation were also studied. The regulations of selected genes associated with adherence were evaluated quantitatively and qualitatively by using real time and reserve transcription-polymerase chain reaction. In addition, the structure of EPS and biofilm maximum depth upon exposure with nicotine were analysed using confocal laser scanning microscope (CLSM). The results indicated that nicotine enhanced the growth of oral candida and bacteria in both planktonic and biofilm cells. Cell surface hydrophobicity and the expression of hyphal wall protein 1 (HWP1) and agglutinin-like sequences 3 (ALS3) of C. albicans and C. parapsilosis were found to increase in relative to the nicotine concentrations used. We also found that nicotine could increase the expression of Streptococcus sp. adherence-associated genes such as surface protein antigen (spaP), glucosyltransferase (gtfB), and glucan binding protein B (gbpB). Interestingly, the iv thickness of biofilm was increased as the nicotine concentration increases. The data concluded that nicotine can promote the growth of S. sanguinis, S. mutans, C. albicans and C. parapsilosis and influences its adherence on the plastic wells which mimic tooth surfaces. The findings of the study may have implications in improving and providing better healthcare for heavy smokers to reduce dental biofilm. In addition, the overall outcomes of this research may be applied to smoking cessation measures in smokers and aid in providing guidelines for control and preventive measures of dental biofilm associated oral diseases