دو ماهنامه میکروب شناسی پزشکی ایران
سال هشتم شماره 1 (بهار 1393)

The role of Mycoplasma super antigens in inflammatory diseases such as rheumatoid arthritis (RA) is taken into consideration. Therefore, the aim of this study was to diagnosis of Mycoplasma pneumoniae in synovial fluid (SF) of patients with RA. In this study, 131 synovial fluid samples of patients with RA were collected during 3 years (2011- 2013). Mycoplasma pneumoniae ATCC: 29342 strain was used as control. The genome of samples is extracted separately and PCR protocol by M. pneumoniae species and mycoplasma genus identifier primers was carried out. The PCR product was confirmed by sequencing. The results of this study showed that this molecular diagnosis method is able to detect M. pneumoniae in the synovial fluid of patients with RA. So that M. pneumoniae species was confirmed in 30 samples (22.9%) and Mycoplasma genus detected in the 70 sample (53.4%). based on the results of this study, the PCR molecular method was able to detect of the Mycoplasma genus and also M. pneumoniae species in the synovial fluid of patients with RA. The results indicated that M. pneumoniae can be a probable cause of rheumatoid arthritis disease. This finding may help the specific treatment of RA.

Clostridium perfringens are classified into five toxin types A to E, on the basis of production of Alpha, Beta, Epsilon and Iota toxins. Some strains are able to produce enterotoxin, can cause food poisoning in human. The bacteria are able to produce NetB and TpeL toxins which are virulence factors in necrotic enteritis in poultry. The aim of this study was to determine the toxin profile of C. perfringens strains isolated from packed chicken portions using Single and Multiplex PCR assays. In a crossectional study, 180 sample of chicken portions including wing (n=50), liver (n=50), neck (n=50) and gizzard (n=30) were collected randomly and examined for C. perfringens contamination. For this purpose all of samples were cultured on the 7% sheep defibrinated blood agar, TSN and TSC culture media. All of the isolates were investigated for the presence of alpha, beta, epsilon, iota toxin and virulence (tpeL and netB) genes. In the present study, 6 isolates out of 180 samples, were confirmed as C. perfringens by culture and molecular methods. All of the isolates (100%) were confirmed as cpa and cpb positive strains and belong to type C of C. perfringens. The netB gene was detected in 5 isolates (83.33%) and tpeL gene in three isolates (50%). Our findings show the majority of C. perfringens in broilers are belong to type C which produce necrotic enteritis in poultry and may be transmitted to human through poultry products.

Enterococci are lactic acid bacteria with ability to produce antimicrobial peptides that called enterocins. Target of present study is research on the presence and antibacterial activity of enterocin A among Enterococcus faecium for their potential as alternative antimicrobial compounds, probiotics to control and reduce the pathogenic bacteria in the gastrointestinal tract and bio-preservatives in food or feed and. In this study occurrence of class II enterocin structural gene (enterocin A) in a target of 42 Enterococcus faecium strains, isolated from gastrointestinal tract of animal have been surveyed. E. faecium identification and occurrence of enterocin A gene was performed by PCR method. Cell-free neutralized supernatant of gene positive strains was used to test bacteriocin production and antimicrobial spectrum of supernatant was assayed by wall diffusion method on the gram-positive and negative indicators bacteria Based on our results, 73.8% of isolated strains had enterocin A gene that they inhibited growth of indicator bacteria such as clinical strain of Pseudomonas aeruginosa, Salmonella enteric PTCC1709, Listeria monocytogenes, Bacillus cereus and Bacillus subtilis. Studied enterocins have growth inhibitory spectrum on Gram-positive and Gram-negative bacteria especially against pathogenic bacteria in the gastrointestinal tract. Therefore, these strains have the potential to explore and use as, alternative antimicrobial compound and bio-preservatives in food or feed or as probiotics.

Sea cucumber has different properties through having different biological compounds. In this study, the antibacterial activity of the extracts of the sea cucumber Holothuria leucospilota was investigated on Escherichia coli. Sea cucumber fishery samples after washing were crushed and powdered. The methanol, chloroform and hexane extracts of body wall, gonads and intestine were prepared. The antibacterial effect of the extracts was studied on the Escherichia coli at several concentrations. Also minimum inhibitory concentration and minimum bactericidal concentration of the extracts were studied against bacteria. The results showed that methanol extracts had no effect, chloroform extracts showed antibacterial activity at concentrations of 5 and 10 mg per ml. Hexane extract of wall at concentrations of 5 and 10 and the intestine hexane extract at a concentration of 2.5, 5 and 10 mg per ml have antibacterial activity against bacteria. None of the concentrations of the gonadal hexane extract showed any antibacterial activity. Only the hexane extract of intestine killed the bacteria at a concentration of 10 mg /ml. According to the findings of this research, extracts of sea cucumber Holothuria leucospilota can be used in preparation of natural antimicrobial drugs as a valuable source of compounds with potential of antibacterial.

Several studies have been done that showed honey has been therapeutic effects on infection disease like Pseudomonas infections. Our aim of this study is evaluation of the antibacterial activity of mono floral and multi floral honeys from different origin of Iran on growth of Pseudomonas aeruginosa and compare their activities with artificial honey and antibiotics. Antimicrobial effect of honey was determined by disc diffusion and broth dilution method on 5 different concentration of honey. The highest inhibition zone (16 ± 1/52 mm) was recorded from persimmon honey in disc diffusion method. In this study، the minimum inhibitory concentration (MIC) for manna honey and other natural honeys obtained 25% and 12. 5% respectively. While P. aeruginosa was inhibited at concentration of 50% (ml/ml) of artificial honey. This study showed that honey has a significant antibacterial effect on P. aeruginosa. There is a direct link between the concentration of honey and inhibition zone.

Identification of lactic acid bacteria of traditional cheeses is the first step of developing new starters in order to protect from national genetical resources and to product industrial cheese with desirable texture and organoleptic characteristics same as traditional cheeses. After traditional cheeses collection (24 samples of 8 different traditional cheeses from West Azerbaijan), identification of Lactobacillus species was performed using a specific culture (MRS broth). In present study, from a total of 118 isolates of lactobacilli were determined. Lactobacillus plantarum (24%), Lactobacillus casei (20%) and Lactobacillus agillis (18%) from facultative heterofermentative Lactobacilli and Lactobacillus delbrueckii (21%), Lactobacillus helveticus (14%) and Lactobacillus salvariu s (3%) from obligative homofermentative Lactobacilli were found to be more dominant species. So for achievement to organoleptic characteristics of traditional cheeses in industrial productions, mixed starters including dominant Lactobacillus species identified in cheeses can be employed.

Biosurfactants are amphipathic molecules with both hydrophilic and hydrophobic moieties that allow them to reduce surface tension. Biosurfactants have several advantages over the chemical surfactants, such as lower toxicity, higher biodegradability and better environmental compatibility. A promising group of glycolipid biosurfactants are sophorolipids that are produced by a group of yeasts. So the aim of this study was isolation of yeasts from bee bread of honey bees. The samples were prepared from bee bread of honey bee, Apis mellifera. The yeasts were isolated on YMG culture medium. Hemolysis and oil spreading techniques were performed for screening of biosurfactant-producing isolates. The extracted biosurfactants were characterized by thin layer chromatography (TLC) and infrared spectroscopy (FTIR). From a total of 35 isolated yeast strains, 10 isolates had positive oil spreading test. The HG12 isolate showed the highest level of oil spreading character.The TLC and FTIR examinations of the purified Glycolipid biosurfactant confirmed its structure as sophorolipid. This is the first report of production of a sophorolipid biosurfactant from yeast in Iran.

Nutritional and economic importance of milk and dairy products is undeniable. In a day, Millions of people use from these products in their daily deals but unfortunately the hygienic quality of milk and dairy products can be changed due to presence of microbial pathogens. Salmonella enteritidis and Salmonella typhimurium are two important milk-borne pathogens. Their pathogenicity is occurred by several putative virulence genes. This study was carried out for investigate the prevalence of Salmonella spp., Salmonella enteritidis and Salmonella typhimurium in milk and dairy products and study the presence of their virulence factors. Totally, 360 milk and dairy products were collected from Isfahan province and were immediately transferred to the Food Microbiology Research Center of Islamic Azad University of Shahrekord. All samples were cultured and their positive results were subjected to PCR method in order to determine the exact incidence rates of Salmonella spp., Salmonella enteritidis and Salmonella typhimurium and their virulence genes. Totally, 1.66% of samples were Salmonella positive. The incidence of Salmonella enteritidis and Salmonella typhimurium were 0.27% and 0.83%, respectively. Raw sheep milk had the highest prevalence of Salmonella spp. (7.5%). All of the Salmonella enteritidis and Salmonella typhimurium isolates harbored their certain virulence factors. To our best knowledge the present study is the first prevalence report of Salmonella spp., Salmonella enteritidis and Salmonella typhimurium in raw sheep and goat samples in Iran. Consumption of pasteurized milk and dairy products can reduce the risk of salmonellosis.