نشریه میکروبیولوژی دامپزشکی
سال هجدهم شماره 1 (پیاپی 44، بهار و تابستان 1401)

Chicken meat is one of the most perishable foods. coating and modified atmosphere packaging are the new methods to increase its shelf-life. The present study was conducted to evaluate the effect of carrageenan edible coating () containing (Mentha longifolia) essential oil () under modified atmosphere packaging (% O ، % N ، % Co) on the quality of chicken meat during refrigerated storage. Samples were separated into three groups: uncoated (control), coated with carrageenan and coated with carrageenan contained essential oil (Mentha longifolia) were stored at refrigerator temperature for days and microbial (bacterial count of psychrotrophic and mesophilic), chemical properties (pH, total volatile nitrogen (TVN) and thiobarbituric acid (TBA)) and sensory characteristics (appearance, muscles elasticity, odor and color). Were evaluated at regular intervals storage time (days , , , , , , and). The results of the bacterial analysis showed that coating with carrageenan and carrageenan- essential oil coatings had significant effects on delaying the increasing trend of psychrophilic and mesophilic bacterial counts as compared to control. Chemically, carrageenan- essential oil treatment showed lower TBA, TVN and pH values than the other two groups during storage (P <). The carrageenan and carrageenan contained essential oil treatments that maintained sensorial factors at acceptable levels for and days respectively. According to the results, the carrageenan and carrageenan- essential oil coating could extend the shelf life of chicken fillets for and days.

Eryngium planum (local name: chouchaq) a native plant of northern Iran, contains phenolic acids and other compounds with antibacterial properties. In this study, the antibacterial effect of the methanolic extract of E. planum was investigated on clinical isolates of S. aureus and E. coli. The methanolic extract of E. planum was prepared by maceration and S. aureus and E. coli were isolated from human and animal clinical cases. The disc diffusion test was used to evaluate the antimicrobial activity of the extract, compared with standard antibiotics and the results were analyzed by Tukey's test. The effects of extract at a concentration of mg/ml on human S. aureus and mg/ml on animal S. aureus were significantly higher than gentamicin. The effect of the extract with a concentration of mg/ml on human and animal E. coli was similar to gentamicin and no significant difference was observed between them, but the effect of the extract with a concentration of mg/ml on animal E. coli was significantly higher than gentamicin and the effect of the extract on animal and human E. coli was significantly higher than ciprofloxacin (P < ). Based on the results, the methanolic extract of E. planum at a concentration of mg/ml had a favorable inhibitory effect on S. aureus and E. coli, which indicates the antimicrobial properties of this plant.

Equine Viral Arteritis (EVA) is a transmissible disease in the horse population, which caused by RNA viruses of family Arteriviridae. Abortion in mares, lethal pneumonia and enteritis in young foals may occur in infections. The aim of this study was to detection of Equine Arteritis Virus antibodies in horse population of Kerman city and Bojnurd city of Iran for the first time. sera were collected from apparently healthy horses randomly from the horse population of Kerman city and Bojnurd city in the period from Sep to Feb . The samples were examined by indirect ELISA test with commercial kit. The results indicate that the seroprevalence of EAV infection in the region is . EVA seropositivity was not associated with age, sex, breed and keeping system. According to the present study, EVA existed in the horse populated areas of Iran and Therefore, implementation of control programs to prevent EVA outbreaks seems necessary.

Nano-scale biological compounds that have unique physical and chemical properties have become effective in recent years. Today, due to the cost of production and compatibility with the environment, the use of extract in the synthesis of nanoparticles has received attention. The present study was conducted with the aim of investigating the antimicrobial properties of silver nanoparticles synthesized from the hydroalcoholic extract of Urtica dioica on Staphylococcus aureus and Pseudomonas aeruginosa.In this experimental study. First, the hydroalcoholic extract of Urtica dioica nettle extract was prepared, then, by adding silver nitrate salt with a concentration of mM to the extract, the reaction was carried out at room temperature and after the color change of the reaction solution containing nanoparticles, the physical and chemical properties of silver nanoparticles synthesized using From SEM, XRD and UV-vis was studied. Antimicrobial effect of silver nanoparticles with different concentrations was evaluated by MIC method.The maximum absorption of silver nanoparticles was recorded at a wavelength of nm. The average diameter of the synthesized nanoparticles was the results of the antimicrobial test showed that the synthesized silver nanoparticles have a positive effect on both bacteria. The MIC concentration of nanoparticles for Staphylococcus aureus was μg/ml and for Pseudomonas aeruginosa μg/ml.It seems that silver nanoparticles synthesized with the hydroalcoholic extract of Urtica dioica have antibacterial activity and can probably be used as an antimicrobial candidate.

Pets such as dogs and cats are potential sources of transmissible infections such as Yersinia enterocolitica to humans, especially children.The gastrointestinal tract of these animals keeps the infection in them and can be considered as a carrier for their owners. This study was conducted with the aim of investigating the frequency of Yersinia enterocolitica infection in apparently healthy dogs and cats and their owners in Isfahan city. For this purpose, fecal swabs were collected from 115 apparently healthy dogs and cats and their owners, and Yersinia contamination and the presence of virulence genes were investigated using culture and molecular methods. The results obtained in the present study showed Yersinia enterocolitica infection in 32% of dogs, 4% of cats, 24% of dog owners and 4% of cat owners. A significant relationship was observed between age, disease and the way of keeping with the prevalence of Yersinia enterocolitica in dogs, and the level of infection of dog and cat owners was directly related to the infection of dogs and cats. Antibiogram results showed that the highest sensitivity and resistance were related to tetracycline and ciprofloxacin antibiotics, respectively. Infected animals may be the main source of infection. These results can be useful in prevention and control programs.

Pneumonic Mennheimiosis caused by Mannheimia (Pasteurella) haemolytica is one of the most important etiological agent of pneumonia in cattle, sheep, and goats throughout the world. This study was conducted in Semnan province, North East Iran to determine the incidence and prevalence of M. haemolytica antigens using immunohistochemistry labelling of formalin-fixed, paraffin-embedded tissues of goats with natural pneumonia and slaughtered in slaughterhouse and then comparing its results with the results of bacterial isolation. For this purpose, a total of goat lungs slaughtered at abattoir were grossly examined and pneumonia was detected in cases ( %). With the exception of verminous pneumonia which were observed in cases, bacteriological and immunohistochemical examinations were performed on pneumonic lungs. The presence of M. haemolytica and its antigens were detected in ( ) and (% ) out of pneumonic lungs respectively. Bacterial antigens were found most frequently in the cytoplasm of bronchial and bronchiolar epithelial cells, in the degenerating leukocytes in the alveoli, and in the degenerating leukocytes in the necrotic area, less frequently in the epithelial cells of bronchial glands, and lymphoid cells. In conclusion, detection of M. haemolytica antigens in pneumonic lungs using immunohistochemistry appear to be more reliable compared to bacterial isolation.

Background of the study:

 In the cultured and ornamental fish industry, fungal organisms threaten young and adult cultured populations and lead to the decay of eggs and larvae. Fungal Infections Secondary infections in fish are caused by primary parasitic, viral and bacterial organisms.

In this research, the number of fungal infections and their type of infection in ornamental fish should be determined.

This study was conducted on ornamental fish with clinical symptoms. The samples were obtained from different places. After identifying the fungi, their abundance was checked by culture and PCR.

Out of the total of investigated cases, the skin and gills had lesions in cases, and the result of mushroom culture was positive. In the PCR analysis of these samples, the fungal species identified by gene sequence were Cladosporium, Candida, Penicillium, and Aureobasidium pullulans and Rhodotorula yeast. Pathological lesions in the gills were dark and hyperemic; under the microscope, epithelial cells were shed, and leukocytes were present. It was seen in the skin as macroscopic and microscopic wounds. Finally, these fungi are responsible for forming lesions seen under certain conditions, such as environmental instability and immunosuppressive factors.

Cryptococcosis is usually a subacute or chronic infection in nature and Cryptococcus neoformans is the cause of this infection.This yeast is found in bird droppings and can be transmitted through dust and inhalation. People with immunodeficiency disorders are at high risk for this infection. In this study, samples were collected from nasal mucosa of domestic cats. The suspension was prepared samples cultured in S, Sc and BHI media and incubated at and °C. After hours, we assessed sample by using Chinese Cotton Blue stain solution. Afterwards, samples were identified by using sugar fermentation tests, urea hydrolysis and germ tube formation. We examined suspected colonies of Cryptococcus neoformans by PCR. The results shown a variety of filamentous fungi such as Penicillium, Aspergillus, Alternaria, Scopulariopsis, Mucor, Rhizopus and yeasts such as Rhodotorula, Candida albicans, Candida Sp, Pachia were isolated and Cryptococcus neoformans were not isolated. Molecular tests of suspected samples of Cryptococcus were negative, The reason of this results could be personal hygiene in the case of domestic cats, keeping them indoor and not have contact with other animals and outdoor environments.