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Leptospirosis is a zoonotic disease with a high incidence rate in many parts of the world due to the presence of various hosts for the pathogenic Leptospira. Tropical, subtropical and humid regions are suitable for long-term survival of the bacterium. Because of the temperate and humid climate, northern areas of Iran are suitable for pathogenic Leptospira and outbreak of the disease. Therefore, identification of infected areas is important from a public health and economic point of view. Previous studies show that the incidence rate of leptospirosis is increasing every year. Therefore, accurate diagnosis, control and prevention of this disease seem necessary through vaccination and raising public awareness, especially among high-risk groups. Today, diagnostic methods including immunofluorescence assay, enzyme-linked immunosorbent assay, microscopic agglutination test (MAT) and polymerase chain reaction (PCR) are used to diagnose the leptospirosis. MAT is the gold standard test for the diagnosis of leptospirosis with extensive applications in Iran. Due to the importance of this disease and its high prevalence in recent years, the present study aimed to investigate the epidemiology and diagnosis of leptospirosis in Iran.

ABSTRACT Background and Objectives: Keratinase is an enzyme commonly used in the production of detergents, cosmetics, drugs, leather, and other industries. Considering the high cost of traditional methods for decomposition of feather, hair, hooves, nails, and wool that contain high levels of keratin, their biodegradation with keratinase-producing bacteria can be a valuable solution. The present study aimed for isolation and molecular identification of keratinase-producing bacteria in Qeshm Island and Peyposht village in Iran. Methods: Water and sludge samples from the Qeshm Island and Peyposht village were collected. The bacteria isolates were screened for keratinase production using the Lowry method. Effect of pH and temperature was assessed on the production of keratinase and on the growth of the isolates. Colony-polymerase chain reaction was used for molecular identification of the isolates. Results: Bacillus berevis and Enterobacter cloacae were isolated in this study. Keratinase production in B. berevis was highest at pH 7.5 and 35 °C. In addition, the highest level of enzyme production by E. cloacae was observed at pH 7 and 37 °C. Conclusion: It seems that the bacterial strains isolated from sludge in the study area have relatively favorable keratinase production capacity. Keywords: Bacteria, Colony PCR, Identification, Keratinolytic protein, Sewage.

ABSTRACT Background and Objectives: Development of ecofriendly processes for the synthesis of metal nanoparticles is of great importance in the field of nanotechnology. Microorganisms such as bacteria could be suitable candidates for bioproduction of nanoparticles due to their simplicity and high compatibility with the environment. The aim of this study was to use bacteria isolates from the effluent of wastewater treatment plants to produce silver nanoparticles. Methods: For identifying silver-resistant microorganisms, we used the agar diffusion method using PHG II medium containing 0.5 mM silver to determine minimum inhibitory concentration. Bacterial identification was done with biochemical testing and polymerase chain reaction (colony PCR). Finally, silver nanoparticles were produced in the desired bacteria, and the properties of these nanoparticles were studied. Results: We found five silver-resistant bacteria among which Stenotrophomonas maltophilia strain MS8 showed the highest resistance (MIC= 6 mM). The bacterium was able to synthesize silver nanoparticles in spherical shapes. The results obtained from visual observations using UV-VIS, TEM and XRD showed that the bacterium was able to reduce silver ions into silver nanoparticles with maximum size of 20 nm. Conclusion: Based on our findings, this bacterium could be useful for biosynthesis of silver nanoparticles. KEYWORDS: Bacteria, Biosynthesis, Minimum Inhibitory Concentration.