[Isolation, morphological characterization and host range determination of Iranian bacteriophages against Salmonella reference collection]

Background and Aim: Salmonella spp. is important in medicine. Most related infections are self-limited. Antibiotics are used for high risk patients such as children, old individuals and immune-compromised patients. Overuse of antibiotics has led to increased emergence of multi-drug resistant bacteria which are life-threatening. Phage therapy is an alternative method to reduce antibiotic use

Materials and Methods: Waste water samples were collected from sewage system of Rasht City twice a month. Prepared suspensions of Salmonella reference collection A [SARA] number 1, 6 [S. typhimurium] and 46, 48, 51 [S. paratyphi B] and double LB broth were mixed with filtrated waste water. After centrifugation and filtration, serial dilutions were prepared and phages were isolated. Morphologic characteristics were determined using TEM [Transmission electron microscopy]. Finally, to assess the spectrum effect of the bacteriophages, we determined host range against 19 SARA strains

Results: Clear plaque formation on double layer LB agar indicated lysis of the test strains by isolated phages. The results of host range showed that some of the phages were able to lyse a number of other bacteria of SARA collection. Imaging with TEM indicated that the isolated phages against SARA collection belonged to Siphoviridae and Podoviridae families

Conclusion: This is the first report of phage isolation against Salmonella reference collection in Iran. SARA no. 51 [S. paratyphi B] was lysed by S. typhimurium phage. It means that the isolated phage may lyse S. typhi, which is an important human pathogen

Detection and prevalence of polyoma virus BK among Iranian kidney transplant patients by a novel nested-PCR

BK virus is an increasingly recognized pathogen in transplant recipient patients associated with nephropathy and emerged as a cause of allograft failure linked to immunosuppressive regimens in renal transplant recipients. This study develops a sensitive PCR method to detect the viremia and viruria as well as the incidence of BK virus infection in renal transplant recipients. A nested PCR method was developed and a total of 45 paired serum and urine samples from renal transplant recipient patients were collected and tested with the developed assay. The threshold of the developed detection assay was 10 copies/ul of BKV DNA in samples. Our results also indicated that about 40% of the urine and 26.7% of serum samples were positive for BKV in renal transplant patients in this study. This Nested-PCR method was found a specific, sensitive and simple procedure for detection of viruria and viremia of BK virus in renal transplant recipients