ABSTRACT
The aim of this study is to investigate antibacterial effects of immunodominant proteins isolated from the venom of Naja Naja Oxiana snake against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. The innate immune system is an important line of defense against bacterial diseases. Antibacterial peptides and proteins produced by snake venoms have recently attracted significant attention due to their relevance to bacterial diseases and the potential of being converted into new therapeutic agents. Identification of immunodominant proteins of the venom of Naja Naja Oxiana snake was performed by SDS-PAGE and western blot analysis. Identified proteins were isolated directly from preparative gel electrophoresis by Electro-elution. In the next step, antibacterial effects of immunodominant proteins were tested against several strains of clinical isolates, including S.aureus, B.subtilis [Gram-positive bacteria] P.aeruginosa and E.coli [Gram-negative bacteria] using broth microdilution and disc-diffusion assays. In order to compare the results of the disc-diffusion assay, antibacterial effects of several antibiotics [Gentamicin, Ampicillin, Penicillin, Amoxicillin and Ciprofloxacin] were also examined using the same conditions. Results showed that immunodominant proteins of [14, and 65kDa] with high immunogenicity were very effective in inhibiting the growth of two Gram-positive bacteria [S.aureus, B.sub] that were tested. However, they were only moderately effective in inhibiting the growth of the two tested Gram-negative bacteria [P.aeruginosa and E.coli]. However, immunodominant proteins of 22 kDa and 32kDa with high immunogenicity, showed slight effectiveness in inhibiting the growth of two; the Gram-positive and Gram-negative bacteria that were tested. To the best of our knowledge, these immunodominant proteins are novel antigens for potent antimicrobial effects against two gram-positive bacteria [S.aureus, B.subtilis ] and less antimicrobial effect against two gram-negative bacteria [E.coli, P.aeruginosa] that were prepared
ABSTRACT
OBJECTIVES: Leptospirosis is a zoonosis caused by leptospires, in which transmission occurs through contact with contaminated biological fluids from infected animals. Rodents can act as a source of infection for humans and animals. The disease has a global distribution, mainly in humid, tropical and sub-tropical regions. The aim of this study was to compare culture assays, the microscopic agglutination test (MAT), polymerase chain reaction (PCR), and nested PCR (n-PCR), for the diagnosis of leptospirosis in rodents in Mazandaran Province, northern Iran. METHODS: One hundred fifty-one rodents were trapped alive at 10 locations, and their urine and kidney samples were collected and used for the isolation of live Leptospira. The infecting serovars were identified and the antibody titres were measured by MAT, using a panel of 20 strains of live Leptospira species as antigens. The presence of leptospiral DNA was evaluated in urine and kidney samples using PCR and n-PCR. RESULTS: No live leptospires were isolated from the kidney and urine samples of the rodents. Different detection rates of leptospirosis were observed with MAT (21.2%), PCR (11.3%), and n-PCR (3.3%). The dominant strain was Leptospira serjoehardjo (34.4%, p=0.28), although other serotypes were also found. The prevalence of positive leptospirosis tests in rodents was 15.9, 2.6, and 2.6% among Rattus norvegicus, R. rattus, and Apodemus sylvaticus, respectively. CONCLUSIONS: Leptospirosis was prevalent in rodents in Mazandaran Province, northern Iran. MAT was able to detect leptospires more frequently than culture or PCR. The kidney was a more suitable site for identifying leptospiral DNA by n-PCR than urine. Culture was not found to be an appropriate technique for clinical diagnosis.