Biofouling in the oral cavity often causes serious problems. The ability of Streptococcus mutans to synthesize extracellular glucans from sucrose using glucosyltransferases (gtfs) is vital for the initiation and progression of dental caries. Recently, it was demonstrated that some biological compounds, such as secondary metabolites of probiotic bacteria, have an anti-biofouling effect. In this study, S. mutans was investigated for the anti-biofouling effect of Lactobacillus fermentum (L.f.)-derived biosurfactant. It was hypothesized that two enzymes produced by S. mutans, glucosyltransferases B and C, would be inhibited by the L.f.-biosurfactant. When these two enzymes were inhibited, fewer biofilms (or none) were formed. RNA was extracted from a 48-h biofilm of S. mutans formed in the presence or absence of L.f. biosurfactant, and the gene expression level of gtfB/C was quantified using the real-time polymerase chain reaction (RT-PCR). L.f. biosurfactant showed substantial anti-biofouling activity because it reduced the process of attachment and biofilm production and also showed a reduction in gtfB/C gene expression (P value < 0.05).

Rapid and accurate diagnosis and identification of Leishmania sp causing cutaneous leishmaniasis is crucial in control and therapeutic programs. The problem of diagnosis with traditional methods is that they have a low sensitivity or time consuming but molecular techniques would be an alternative method for rapid and accurate diagnosis. In this work, tryparedoxine peroxidase gene-based real-time PCR was used for accurate identification of Leishmania spp causing Old-World cutaneous leishmaniasis. In this study, biopsies of specimens were taken from the ulcerative sites in 100 patients and used for direct microscopy, culture in NNN or fixed in alcohol for identification of Leishmania spp using tryparedoxin peroxidase gene-based realtime PCR (qPCR). Using direct microscopy and culture method, Leishmania parasites were isolated from 68 out of 100 patient samples. However, 13 patients with negative finding on traditional tests, had positive results on RT-PCR test. After melting curve analysis of PCR product, Leishmania major in 75 and L. tropica in 4 cases were identified. The sensitivity and specificity of RT-PCR for diagnosis of cutaneous leishmaniasis was 98.7 and 59.8%, respectively. Results of this study showed that RT-PCR was the most sensitive diagnostic test for cutaneous leishmaniasis and represents a tool for rapid species identification.

Objective: Leishmaniasis is caused by differentLeishmaniaspp. Treatment failure (TF) of cutaneous leishmaniasis (CL) is a serious issue that may be due to various reasons, previous studies suggested Leishmania RNA virus (LRV) as a potential cause of TF. Two variant groups of LRV1 and LRV2 are reported. In this study, the presence of LRV1/LRV2 was compared in TF with treatment response (TR) isolates ofL. major. Clinical isolates of 15 TF and 15 TR were collected from CL patients referred to the Health Centers of Isfahan. Genomic DNA was extracted to identifyLeishmaniaspp. using ITS1-PCR–RFLP. Identification of LRV1/LRV2 was performed using SYBR Green Real-Time PCR. The statistical analysis to test relationship between the treatment response with Glucantime and the presence of LRV were performed using SPSS 16.0 with Fisher’s Exact test.Pvalue of less than 0.05 was considered significant.Results: ITS1-PCR–RFLP results showed that every isolate was identified asL. major. The results showed no LRV1 in any of the samples but 7 TR isolates and 2 TF isolates showed positive for LRV2. Statistical analysis showed no significant difference between the presence of LRV2 and response to Glucantime (p-value = 0.1086). Therefore, other mechanisms might be responsible for TF.