نشریه تازه ها در میکروب شناسی دامپزشکی
سال چهارم شماره 1 (بهار و تابستان 1400)

Staphylococcus aureus is an important cause of wound infection and found on the skin of normal human and animal population. Hypericum perforatum and Aloe vera have antioxidant, anti-inflammatery and antibacterial effects, so they can affect on wounds positively together. For this purpose, 40 rats were selected and randomly divided into 4 groups: negative and positive control groups and two groups that treated with Hypericum perforatum and Aloe vera ointments that containing 1 and 4 percent extracts. The wounds were pictured on 0, 3,7 and 14 days after wound creation and the wound healing rates was calculated clinically. Histopathologic stadies were performed on samples collecteal from the wounds in 3,7 and 14 days after wound creation. Finally, the data were analyzed by Anova, Kruskal wallis test. The percentage of wound healing in 3th day in two groups treated with ointment containing extract was higher than other groups. on the 14th day the clinically epithelial tissue of the two groups treated with plant extracts was better than the other two groups. Appendices of the skin like hair follicles are formed in two groups contains extracts, but in the extract of %4 was observed more better than the other three groups becase the sebaceous glands were just observed in this group and quality of epithelial tissue was more better. The results show that ointment containing %4 Aloe vera and Hypericum perforatum extracts have better healing effects and skin beauty results than %1 ointment on wounds that inoculated with Staphylococcus aureus.

Today, the use of biodegradable film is considered due to its environmental friendliness and ability to store biologically active compounds. A novel antimicrobial film was made from the soluble-phase of the Persian gum (SPG) incorporated methanolic extracts of Croccus sativus L. stigmas alone or in combination with nisin. Initially, the minimum inhibitory concentration (MIC) and the minimum bactricidal concentration (MBC) value of saffron and nisin extracts was determined by micro-dilution method and films by disk diffusion method against Listeria monocytogenes, Pseudomonas aerogenesis, Bacillus cereus, Escherichia coli and Salmonella typhimurium. Then saffron extract (MIC: 31.25 mg/ml and MBC: 62.5 mg/ml), and nisin (MIC: 0.256mg/ml) was added to the film formulation. The effect of films on the control of total viable count, Enterobacteriaceae, lactic acid bacteria, Pseudomonas spp., mold and yeast of chicken breast during 12 days of storage at 4±1 °C, was studied every three days. The results showed that nisin compared to saffron extract has a better inhibitory effect on controlling the population of pathogenic bacteria. Also, the addition of nisin to the Persian gum film containing saffron extract showed a synergistic effect (%25) on inhibiting the growth of microbes. Based on the acceptable limit for total viable count (<7 log CFU/g) in fresh poultry meat, growth inhibition of target bacteria and shelf life (up to 12 days), Persian gum + nisin + saffron (MBC) film seems appropriate.

Protozoan diseases caused by Buxtonella sulcata have been one of the constant challenges of the livestock industry in all periods and especially in developing countries such as third world countries such as Iran. Buaxtonella sulcata protozoan is one of the ciliated protozoa of the gastrointestinal tract of ruminants, especially large ruminants. It converts food and ultimately reduces production efficiency in livestock. In this study, 386 calf fecal samples were sampled from Qazvin province. Then we searched and observed the parasite with two methods of microscopic observation and staining and also with the method of molecular analysis. In the molecular method 27 samples were about 7% and in the direct observation method 19 samples about 5% contamination was observed. Statistical analysis was collected and classified by Excel2010 software and then performed by SPSS software using Chi-square test. According to the results, veterinarians need to pay more attention to this protozoan and prevent possible injuries.

One of the main challenges for food producers is to ensure the health and high quality of food during the production, storage and consumption stages. Due to the concern about the safety of chemical antimicrobial compounds, the use of medicinal plants and their health properties in the food industry can ensure the health of consumers. So, the objective of this study was to evaluate antimicrobial activity of essential oil, ethanolic and methanolic extracts of Mentha piperita L cultivated in Medicinal plants farm of agricultural research institute of zabol university, against spoilage and pathogenic microorganisms in food products including Pseudomonas aeruginosa, Bacillus cereus, Micrococcus luteus, listeria monocytogenes and Escherichia coli. The essential oil was obtained by water-distillation using a Clevenger-type system and ethanolic and methanolic extracts were obtained by wet method. Antimicrobial activity of the extracts was measured by agar well diffusion method and minimum inhibitory concentration (MIC) was subsequently determined. The results of diameter of inhibition zone and MIC values indicate that antibacterial activity of the extracts of Mentha piperita L was related to the type of extract and the type of microorganism. Unlike methanolic and ethanolic extracts of Mentha piperita L, which were ineffective in all concentrations against Listeria monocytogenes (0 mm), its essential oil had a strong inhibitory effect on all studied bacteria and with diameter of inhibition zone of 39.3 mm showed the highest significant antimicrobial activity on the same microorganism. In this study, Pseudomonas aeruginosa was the most resistant bacteria to the essential oil and methanolic extracts. The findings of this study indicated that Mentha piperita L essential oil has a strong antimicrobial activity on spoilage and pathogenic microorganisms associated with food.  Therefore, the mentioned compound can be suggested as a very valuable antimicrobial preservative in food.

One of the most important and dangerous bacterial diseases in colonies of mice is rat bite fever. This disease can be transmitted to humans. According to international standards, in the event of a confrontation, control measures, combat and possibly eradication and remove the colony should be taken. The disease caused by Streptobacillus moniliformis bacteria. Symptoms of the disease in humans include high fever, chills, polyarthritis, and skin inflammation. So far, international standards for determining the infection of laboratory animals with this infectious agent have not been performed in Iran. In this study, the prevalence of this bacterium, in the colony of Razi Institute NIH Laboratory mice was studied in 1398. Number of 66 mice from a breeding colony were randomly selected and were examined by PCR method for presence of this bacterium. No positive samples were observed. According to the instructions used, it can be concluded that with 99.9% confidence, there was no infection with Streptobacillus monilioformis in breeding facilities. The result of this study shows that the observance of hygiene items in this center is done well. However, periodic and continuous monitoring of this bacterium and other important infectious agents should be performed.

Green synthesis of nanoparticles has some advantages including the commitments  to avoid  harmful chemicals, clean process, eco-friendly, easy preparation, economical and control on size and shape of particles. In this study, water extract of Saturaja rechengri Jamzad was prepared and titanium nanoparticles  produced using green and ultrasound techniques. Then, in order to characterize the nanoparticles, UV analysis, energy dispersive x-ray spectroscopy and TEM and SEM analysis were performed. MIC and MBC of nanoparticles against E. coli O157:H7 and L. monocytogenes and cytotoxicity in 12.5, 25, 50, 100 and 200 mg/ml on HT-29 and HEK-293 cell lines were also determined. Nanoparticles had absorption at 352 nm which showed synthesis of titanium nanoparticles using Saturaja rechengri Jamzad extract. Spherical shape of nanoparticles was detected in colloidal solution with 37.4 to 49.6 nm. Titanium nanoparticles could stop the growth of E. coli O157:H7 and L. monocytogenes at 20 µg/ml. The nanoparticles did not revealany cytotoxic effect on the  normal cells, while it was  stop the growth of 50% of cancer cells at 183 µg/ml. The results of this study decreased the anxiety of using titanium nanoparticles and increased the potential  of using this nanoparticle in food packaging  to finally extend shelf life of food.

Fruits and juices obtained from them are of special importance as the main pillars of providing human nutritional needs and are among the most desirable drinks that contain salts, vitamins and antioxidants. They provide a significant part of the body's needs; However, lack of hygiene can provide the basis for contamination of fruit juices with pathogenic bacteria. Escherichia coli is an indicator of feces contamination and its presence indicates lack of hygiene in the preparation, production and storage of food. The purpose of the present study is to investigate the level of Escherichia coli contamination of traditional fruit juices in Iran. In order to receive the studies conducted, in the databases Medline, Science Direct, Scopus, Springer, PubMed, Wailly, Elsevier and Google scholar, as well as the domestic databases of the country including: Mogiran, Irandoc, Civilica, Academic Jihad Scientific Information Center (SID) was used as the search criteria and then searched using keywords with the title from 1380 to 1401 (2000-2022) and 19 articles related to the subject of this research were found. According to the investigations, the contamination of traditional fruit juice with Escherichia coli bacteria in all the studies was positive and it is more than the national standard of Iran, Europe and America. Considering the high microbial load and the lack of hygiene in traditional fruit juices, it is necessary that the production and supply of these products is accompanied by mandatory training of operators and to prevent the continuation of the activities of centers that do not comply with health standards Action will come.