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Background:Vibrio cholerae causes diarrhoeal disease that afflicts thousands of people annually. V. cholerae is classified on the basis of somatic antigens into serovars or serogroups and there are at least 200 known serogroup. Two serogroups, O1 and O139 have been associated with epidemic diseases. Virulence genes of these bacteria are OmpW, ctxA and tcpA.Objectives:Due to the importance of V. cholerae infection and developing molecular diagnostics of this organism in medical and microbiology sciences, this study aimed to describe molecular characterization of V. cholerae isolated from clinical samples using a molecular method.Materials and Methods:In this study, 48 samples were provided during summer 2013 (late August and early September) by reference laboratory. Samples were assessed using biochemical tests initially. The primer of OmpW, ctxA and tcpA genes was used in Polymerase Chain Reaction (PCR) protocols. Enterobacterial Repetitive Intergenic Consensus (ERIC)-PCR and Repetitive Extragenic Palindromic (REP)-PCR methods were used to subtype V. cholerae.Results:In this study, from a total of 48 clinical stool samples 39 (81.2 %) were positive for V. cholerae in biochemical tests and bacteria culture tests. The PCR results showed that of 39 positive isolates 35 (89.7%), 34 (87.1%) and 37 (94.8%) were positive for ctxA, tcpA and OmpW gene, respectively. Also, in the REP-PCR method with ERIC primer strains were divided into 10 groups. In the REP-PCR method with REP primer, strains were divided into 13 groups.Conclusions:Polymerase chain reaction has specificity and accuracy for identification of the organism and is able to differentiate biotypes. Enterobacterial repetitive intergenic consensus sequence is one of the informative and discriminative methods for the analysis of V. cholerae diversity. The REP-PCR is a less informative and discriminative method compared to other methods for the analysis of V. cholerae diversity.

Background:Staphylococcus aureus strains that are Panton–Valentine leukocidin (PVL) positive cause severe skin and soft tissue infections as well as necrotizing pneumonia. The presence of PVL gene is a marker for methicillin-resistant S. aureus; therefore, survey on prevalence and phylogenetic distribution of PVL is of great importance for public health. The aim of this research was molecular epidemiology survey of S. aureus PVL positive, isolated from two tertiary hospitals of Sanandaj.Materials and Methods:A total of 264 staphylococci isolates were collected from clinical specimens, hospital personnel and hospital environment of two tertiary hospitals of Sanandaj, in 2012 (Toohid and Besat). Bacterial cultures and biochemical tests were performed for S. aureus detection. Then, polymerase chain reaction (PCR) and repetitive sequence-based PCR (rep-PCR) were used for the determination of prevalence and molecular epidemiology of S. aureus PVL, respectively. Data were analyzed using the Fisher's exact test (P < 0.05).Results:From 264 staphylococci isolates, 88 (33.33%) were detected as S. aureus. Furthermore, 20 out of 88 (22.72%) strains of S. aureus were PVL positive according to PCR results. Rep-PCR showed six main clusters of S. aureus samples. PVL had similar clonality between different samples. No significant relationship was observed between PVL positive S. aureus and rep-PCR patterns (P = 0.98).Conclusion:These results showed that a clone of S. aureus PVL positive has spread between the community and hospital settings. Therefore, appropriate measures are required to prevent the spread of staphylococci and other bacteria in hospitals.

Background: Nano composites are widely used in medical sciences recently. Identification of chemical mutagens is an important issue in drug safety. Objectives: The aim of this study was to investigate mutagenicity and antibacterial activity of various generations of poly (amid amine) (PAMAM) dendrimers and agonic acid poly (amid amine) (PAMAM) Nano composite G2 on enteric pathogenic bacteria. Materials and Methods: Disc diffusion method, MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) determination were performed for antibacterial activity survey. Mutagenic properties were determined by Ames assay. Results: Various dilutions of PAMAM generations (G2, G3, G4 and G5) and agonic acid PAMAM Nano composite G2 had antibacterial effect on Escherichia coli, Salmonella enterica, Salmonella typhimurium, Enterococcus faecalis and Staphylococcus aureus. In Ames assay, reverted colonies were increased by PAMAM generations increasing. Moreover, reverted colonies Ames assay were lower when Nano composite G2 was applied. Conclusions: PAMAM generations and agonic acid PAMAM Nano composite G2 contain compounds with therapeutic potential and antibacterial characteristics, which can be used in medicine. Because some chemicals have mutagenic and carcinogenic properties, identification of these chemical is of great importance.