جستجوی مقالات مرتبط با کلیدواژه « Staphylococcus aureus » در نشریات گروه « دامپزشکی »

Staphylococcus aureus, a gram-positive bacterium known for its resistance to desiccation and production of enterotoxins, is a prominent foodborne pathogen causing gastroenteritis and vomiting through its enterotoxin genes. This study aimed to assess the prevalence of S. aureus strains carrying enterotoxins A and B in traditional dairy products, salads, and nuggets distributed in Shahrekord. Additionally, antibiotic resistance profiles of these isolates were investigated. A total of 300 food samples were randomly collected from the Shahrekord market in spring 2023 and processed under sterile conditions to prevent contamination. Results indicated contamination rates of 63% in salads, 5% in nuggets, and 28.43% in traditional dairy products. Specifically, one seasonal salad isolate (0.33%) tested positive for the A gene, and one sandwich isolate (0.33%) contained the B gene. Antibiotic susceptibility testing revealed a high resistance rates to ampicillin (86.18%) and gentamicin (88.8%), while resistance was the lowest for imipenem (38.6%) and tetracycline (39.2%). The findings underscore the critical need for stringent regulations to enhance hygiene standards and mitigate the prevalence of toxin-producing microorganisms in fast-food settings, given the serious implications of antibiotic resistance and inadequate oversight on food safety.

The present study was conducted with the aim of evaluating the antibiotic resistance pattern of Bacillus cereus in ice cream, cake, cheese, and infant formula. For this purpose, 600 samples were prepared from food sales centers in Tehran and transferred to the quality control laboratory of the Faculty of Veterinary Medicine of Tehran University of Medical Sciences and cultured on the special culture medium of Bacillus cereus, MYP, which contained polymyxin B supplement and egg yolk. Then, from the pink colonies, gram staining and catalase test were performed and the sensitivity of the isolated bacteria to ampicillin, penicillin, vancomycin, cefazolin, methicillin, cefixime, sulfamethoxazole, trimethoprim, chloramphenicol, cefepime and tetracycline was evaluated based on the disc diffusion method. According to the results, no contamination with B. cereus was observed in any of the cake, cheese and ice cream samples. However, out of 150 infant formula samples, 30 samples were infected with B. cereus (18 samples < 10 CFU/g, 7 samples had 10-102 CFU/g, and 5 samples>102 CFU/g). B. cereus isolated from infant formula has the highest sensitivity to vancomycin (67.76%), tetracycline (70%), and chloramphenicol (33.63%) antibiotics and had the highest level of resistance to penicillin (100%), cefixime antibiotics (100%) and ampicillin (67.96%). The general results indicated a significant prevalence of B. cereus in the tested milk, which due to the growing trend of using milk powder and more importance to the quality and health evaluation of milk powders for consumption, contamination investigation and preventive approaches should be given more attention.

Ready-to-eat foods are convenient for busy people, but the essentialmicrobial risks are those that affect consumers. One of these cases is the presence of Staphylococcus aureus in falafel samples. This study aimed to investigate the number of Staphylococcus aureus in industrial and traditional falafels in Shahryar City. One hundred falafel samples, including 50 traditional and 50 industrial falafel samples, were randomly sampled from the supply centers of this product and taken to the laboratory next to the ice flask. To detect Staphylococcus aureus in the samples from One hundred, it was cultured by the surface culture method. After the end of the incubation, if the bacteria with round and black colonies grow, the directions for the confirmation culture. Biochemistry was evaluated, and finally, positive samples were counted. The results showed that 38 of 50 traditional falafel samples (76%) and 14 of 50 industrial falafel samples (28%) were infected with Staphylococcus aureus. However, avoiding the products sold by street vendors and itinerants without a health card is recommended because they cause occurrences and events caused by the secondary caused by Staphylococcus aureus.

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.

With the growing awareness of the importance of natural extracts with antimicrobial and antioxidant properties, today the food industry is looking for the use these compounds instead of synthetic preservatives. To date, no research has been done to find an optimal mixture of Origanum majorana, Long pepper, and Areca extracts against the gene expression of A and B enterotoxins of S. aureus. Therefore, in this study, we are seeking to provide a mixture of these extracts with the highest anti-enterotoxigenic activity using real-time PCR and mixture statistical methods. If successful, we introduce these extracts as an antagonist against the growth of pathogenic bacteria and the gene expression of enterotoxin of S. aureus. In the first stage, the antimicrobial activity of Origanum majorana, Long pepper, and Areca extracts was studied, which Origanum majorana had the highest antimicrobial activity among them. On the other hand, among the tested bacteria, gram-positive bacteria were more sensitive than gram-negative bacteria. The tested extracts had a synergistic effect on each other against the gene expression of A and B enterotoxins of S. aureus. The mixture of extracts including 47% Origanum majorana extract, 27% Long pepper extract, and 26% Areca extract showed the highest activity against the gene expression.

Shrimp is one of the most popular sources of marine protein worldwide. Due to its high nutritional and economic value, this aquatic product is a major export product in many countries. The shrimp industry includes a significant percentage of all aquaculture products. Contamination of shrimp with pathogenic microorganisms can endanger the health of the consumers. In this regard, the aim of this study is to determine the microbial and chemical characteristics of shrimps supplied in Abadan city. A total of 100 shrimp samples were taken from Abadan city in a simple random manner and transferred to the specialized food hygiene laboratory of Islamic Azad University, Shahrekord branch, in an ice flask and under sterile conditions and microbial tests included Staphylococcus aureus, Escherichia coli, and Salmonella as well as total count and TVN test were performed on the shrimp samples. The results showed that the contamination rate with S. aureus, Salmonella, and E. coli was 14%, 7%, and 2%, respectively. The total count, TVN, and coliform contamination were within the acceptable range. Due to the high importance of E. coli and Salmonella pathogenic microorganisms, it is necessary to monitor closely and as many regulatory institutions as possible to reduce the pollution load.

Biosurfactants are amphipathic compounds that are produced by many microorganisms and show a wide range of biological activities due to their unique characteristics. This study aimed to determine the antioxidant and antimicrobial potential of the biosurfactants isolated from Lactobacillus plantarum, Lactobacillus pentosus, and Lactobacillus casei. The antioxidant activity of biosurfactant was evaluated in vitro conditions using the ability to inhibit 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl free radicals and antimicrobial activities using the diffusion method in agar wells against pathogenic bacteria. The results showed that the inhibitory activity of DPPH and hydroxyl of biosurfactants at a concentration of 5 mg/ml was 78.51-81.99% and 69.51-71.56%, respectively, and the highest antioxidant activity was related to Lactobacillus plantarum (P<0.05). The results of inhibiting microbial growth showed that all biosurfactants had high antimicrobial activity and the antimicrobial activity against Staphylococcus aureus (gram-positive) was higher than other bacteria (gram-negative). No significant difference was observed among different biosurfactants. It seems that biosurfactants obtained from lactobacilli can be used as natural antioxidants and antimicrobials in the food and pharmaceutical industries.