فصلنامه دنیای میکروب ها
سال هفتم شماره 1 (پیاپی 18، بهار 1393)

Winter jasmine, Jasminum nudiflorum, is a tree belonging to Syringa family, which is used in the urban designing. The gall disease in the tree branches caused by Pseudomonas savastanoi is one of the most important diseases in this trees The purpose of this study was to determine the phenotypic and genotypic diversity of P. savastanoi using the BOX PCR.
This experimental study was performed on 23 P. savastanoi isolated from winter Jasmine, Shiraz, Fars, Iran. A IAAL primer and PCR approach was used to direct tracking of the strains. The genotypic characteristics of the P. savastanoi isolates was performed by rep-PCR using BOX primers. The data were next analysed using NTsys-PC software.
Base in numerical analysis of phenotypic characteristics, the strains showed 88% similarity to each other. Using IAAL primer and GES buffer obtained from gall extract, DNA fragments with 454 bp length were amplified. Using rep-PCR option and BOX primer in NTsys-pc software, it was shown that the isolates can be divided into three cluster with 81% similarity. These clusters belonged to Shiraz’s Winter Jasmine isolates, Tehran’s Oleander isolate and Tehran’s Olive as well as standard isolate.
On the basis of our findings, using BOX-PCR it is possible to differentiate the P. savastanoi isolated from different geographical areas and different hosts. Furthermore, this is the first report of direct detection of P. savastanoi from gall using PCR in Iran.

Microbial pigments are nowadays employed in many different industries. Due to carcinogenic ability of sunrays, protection of skin from the harmful ultraviolet rays of the sun by using an effective sunscreen is necessary. This study aimed to evaluate the sun protection factor (SPF) of the pigments obtained from Penicillium and Aspergillus fungi in absorption of ultraviolet radiation, in vitro.
In this study, fungal strains were randomly isolated from air and soil. The fungal pigments were extracted using Water and DMSO solvents. Following a filtration step, these pigment solutions were powdered using lyophilization and drying in room temperature. After three time dilution steps, absorbance of each sample at 200-700nm wavelengths was measured by a spectrophotometer to evaluate SPF of these samples.
Among the species studied in this study, Aspergillus and Penicillium showed the highest absorption at 300 and 290 nm, respectively. These ability is equal to 272 and 140 sun protection factors, respectively, which was the best protective ability of these isolates from ultraviolet rays. Furthermore, the yellowish and black pigments showed the best UV absorption ability.
Based on the results of this study, the pigments isolated from the fungus Penicillium and Aspergillus showed high protection against UV rays. Therefore, it is possible to replace chemical compounds used in cream sunscreen with these natural pigments.

Bacteremia and endocarditis are the most commonly infection in Staphylococcus aureus. Due to curative effects of curcumin, including as an antibiotic, it can be used as a medicine albeit after reducing its side effects. This study aimed to investigate antimicrobial effects of curcumin on methicillin-resistant Staphylococcus aureus in vitro and in an animal model (Balb/C mice).
This pre-clinical study was performed in the department of scientific research and clinical technology of Khomeini Hospital, Tehran. Following synthesis of curcumin-PLGA nanoparticles, their size were measured using scanning electron microscopy and their toxicity were determined by a colorimetric method (MTT). In vitro studies to analyze the effects of this compound on MRSA were performed firstly based on MIC and MBC tests and broth dilution. Next, a same procedure was conducted on blood cultures obtained from infected mice.
A concentration of 6 micrograms of urcumin-PLGA nanoparticles per millimeter showed Antibacterial activity on MRSA strains. A same effect was observed in vivo in mice after treatment by 10 μg/ml urcumin. Furthermore, based on this results, there were no side effects on the normal cells and 75% of the cells treated with the highest concentration of this particle were survived.
these results show that curcumin-PLGA nanoparticles can be used safely for the treatment of bacteremia and endocarditis prophylaxis of infections caused by MRSA.

Clostridium perfringens is one of the most pathogenic species in the clostridium genus. Alpha (α) and epsilon (ε) are the main toxins of this bacteria. This study aimed to express the genes encoding alpha and epsilon toxins of C. perfringens type D in two media (in the base medium and the base medium containing liver powder) and to analyze their toxicity.
The standard strain was inoculated in the base enrichment medium, which half of them were enriched by powder liver. Then, RNAs were extracted and after converting to cDNA using double polymerase chain reaction, the gene expression was investigated on gels. The level of protein expression was measured by spectrophotometery and the cell toxicity of these proteins was determined by minimum lethal dose (MLD) assay.
The electrophoresis of PCR products showed two bands, 324 and 625, which represented successful expression of the genes encoding of alpha and epsilon toxins in both media. The mean cell cytotoxicity of the proteins expressed in the base medium and the base medium containing liver powder were measured 1/4000 and 1/4333, respectively. The mean protein production in the base medium and the base medium containing liver powder were measured 94.39 and 48.01 mg/ml.
This study showed that these genes are expressed in the presence of liver powder. Furthermore, based on the MLD assay in these media, although these genes expressed the genes in the presence of liver powder, this additives did not had any effects on their toxicity.

Fluoroquinolones are successfully being used for treatment of the infections caused by Shigella and multiple antimicrobiaol resistant strains, as well. Mutations in gyr A and carrying qnr are the main mechanisms of resistance to quinolone in microbial strains. This study was aimed to investigate the presence of qnr resistant genes and to evaluate the antibiotic resistant profile in Shigella strains isolated from patients.
Methods and Materials: This study was carried out on 73 Shigella strains isolated from the patients admitted to Mofid’s children medical center, First, the bacteria and strains isolated from the patients were identified based on biochemical and serological tests. The antibiotic resistance profile was determined based on Kirby– Bauer test. The presence of qnr gene was finally determined using PCR reaction. 
The antibiotic resistance profile showed that 97.2% of the isolates were resistant to at least one antibiotic among 18 antimicrobial agents. The most antibiotic resistance ability belonged to trimetoprim+ sulfametoxasol (94.5%) while the lowest antibiotic resistance were seen in the case of treatment with Ciprofloxacin and ceftizoxime (with 100% sensitivity ratio). Totally, 23 Shigella isolates showed resistance against nalidixic acid. Of these, four samples, belonging toS. flexeneri (2 strains), S. Soneie (1 strain) and S. Boiedie (1 strain) carried qnrS gene. None of qnrA and qnrB genes were detected in the isolated strains.
Based on the data, the nalidixic resistance frequency and presence of qnrS gene was significant in these Shigella isolates.

Nowadays Meticillin resistant Staphylococcus aureus (MRSA) is one of the public-health threats due to resistance to agents and anti microbial drugs. The aim of present study was to find the incidence of Meticillin resistant Staphylococcus aureus strains isolated from clinical samples in Ayatollah Mousavi Hospital of Zanjan and their antibiotic resistance pattern as well as recognizing of the mecA gene using PCR.
Materials  & In this descriptive cross-sectional study, 176 specimens were collected from different sections of Ayatollah Mousavi Hospital and assayed. The strains were identified and the resistances of the isolates to 12 kinds of antibiotics were determined using disk diffusion method. Finally, following DNA extraction, mecA gene was analyzed by PCR.
45 Staphylococcus aureus isolates were recovered (25.56%). 26 out of 45 Staphylococcus aureus isolates (57.77%) were confirmed as MRSA. Evaluation of antibiotic resistance showed the greatest resistance to penicillin (100%) and cloxacillin (80.76%), respectively, and the lowest resistance was observed to vancomicin (7.69%).
The findings showed that the prevalence of MRSA was remarkable in the hospital samples and the resistance to methicillin has increased that is a serious warning to the treatment of infections caused by this bacterium.

Chitinase is one of the most important industrial enzymes, which is recently employed especially in the biological control of pathogenic fungi. This study was aimed to isolate and to identify the chitin degrading bacteria obtained from the rhizosphere soil and also to evaluate their antifungal ability.
In this study, 38 soil samples from the rhizosphere of tea plants, Geranium and clover were collected randomly. After serial dilution and growth of the samples on colloidal chitin agar (CCA), the isolates with a clear zone were chosen for further studies. The presence of Chitinase enzyme was measured by a spectrophotometer. Next, we determined the antifungal activity of the isolates against Fusarium solani. Finally, the isolates were identified based on polymerase chain reaction and sequencing 16S rRNA genes.
In this study, only one new strain referred to as Serratia Salahi strains was isolated which showed the chitin degrading activity. The highest enzymatic activity (4.37 U/ml) of this strain was obtained at 30°C after 4 days. Furthermore, the antifungal activity of this bacterium could create 1.5 cm inhibition zone.
According to the findings, this new strain can be used as a natural pesticide and therefore, it is possible to replace the synthetic pesticides with this natural compounds.

A broad application of nanostructures in various fields of science has led to their commercialization in different industries. For instance, application of the antimicrobial activity of nanosilver is one of the consequences of such these strategies. Furthermore, iron oxide nanoparticles is currently employed in microbial cell fixation. In addition, nanoparticles can be used for effective targeted drug delivery to the site of infection. In this term, study on the effect of iron oxide nanoparticles on the physiology of microorganisms is highly demanded. At low concentrations, since iron oxide nanoparticles can act as iron source of microorganisms, they may be eliminated from microbial environment. However, higher concentrations of these particles can result in cell stress and reduction in microbial cell growth. These nanoparticles attach to the microbial cell wall via electrostatic and hydrophobic forces, reducing microbial pathogenicity. The attachment of iron oxide nanoparticles to bacterial cell wall interferes in functionality of cell membrane and thereby increase membranes permeability. These phenomenon increases molecular transportation through the cell membrane and increases productivity in industrial process.