Determination of aflatoxin M1 levels in 1 white cheese samples by ELISA in Gilan province, Iran

Aflatoxin M1 (AFM1) in milk and milk products is considered to pose certain hygienic risks for human health. These metabolites are not destroyed during the pasteurization and heating process. This study was undertaken to determine the presence and levels of aflatoxin M1 (AFM1) in Iranian white cheese consumed in Gilan province (Northern Iran). A total of 90 cheese samples was randomly obtained from retail outlets. ELISA technique was used to determine the presence and the level of AFM1. In 78 of the 90 cheese samples examined (86.66%), the presence of AFM1 was detected in concentrations between 7.2 - 413ng/l. The mean level of AFM1 in positive samples was 151.97 ng/l. AFM1 levels in 21 samples (23.33%) were higher than the maximum tolerance limit (250 ng/l) accepted by the European countries. Aflatoxin high concentration in milk and milk products cause widespread negative impact on public health and demonstrate considerable economic losses for producers. Therefore, it is necessary to establish strategies for reducing aflatoxin levels in animal feed and milk products. © IDOSI Publications, 2012

Prevalence and molecular typing of methicillin-resistant Staphylococcus aureus carrying Panton–Valentine leukocidin gene

Panton–Valentine leukocidin (pvl) toxin is an important virulence factor of Staphylococcus aureus. The main genes are coa and spa for distinguishing and typing of S. aureus isolates. The aim of this study was to investigate antibiotic resistance, presence of mecA and pvl genes, as well as epidemiological typing of these isolates according to polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) method in clinical sample isolated from Rasht city, Iran. A total of 250 clinical samples have been isolated from different hospitals. First, isolates of S. aureus were identified through microbiological methods and their antibiotic sensitivity was determined by disk diffusion agar based on a standard method of Clinical and Laboratory Standards Institute. DNA was extracted by boiling and presence of pvl and mecA genes was investigated by PCR using specific primers. To type these isolates, amplification of fragments of coa and spa genes was done and restriction enzyme digestion pattern was determined by PCR-RFLP method. Among the 250 samples, 50 isolates belonged to S. aureus and results of antibiotic sensitivity showed that 68% (34 samples) of isolates were methicillin resistant. Frequency of mecA and pvl genes among S. aureus isolates were 60% (30 samples) and 20% (10 samples). The PCR of coa gene showed three patterns whereas that of spa gene showed two patterns for enzyme digestion. Result of PCR-RFLP using HaeIII enzymes for coa gene and Bsp1431 for spa gene showed three patterns for enzyme digestion. Recent studies indicated increase in the resistance of S. aureus to different antibiotics, which is a serious problem in the treatment of infections resulting from S. aureus in this region. The result of PCR of pvl showed high frequency of this gene in this region, and coa and spa typing by PCR-RFLP was a useful tool for typing of S. aureus isolates

Antimicrobial Activities of some Plant Extracts against Phytopathogenic Fungi and Clinical Isolates in Iran

Background:       Natural products from plants as environmentally safe options have received attention for controlling various phytopathogenic diseases. In this study, the antimicrobial activities of three plant aqueous and alcoholic extracts (Salvia officinalis, Peganum harmala and Oxalis corniculata) against phytopathogenic fungi (10 fungal isolates associated with diseased tomato fruits) and clinical isolates (10 bacterial isolates) and Candida albicans, as a pathogenic yeast model, were investigated in the Gilan province of northern Iran. Methods:     After phytochemical screening of plant extracts, antimicrobial activity of the extracts evaluated by standard methods for determination of MIC and MBC. Results of the phytochemical screening of aqueous and alcoholic leaf extracts of the selected three plants revealed the presence of saponins, steroids, tannins, glycosides, alkaloids and flavonoids. Results:     All three extracts of the plants tested showed varying degrees of antimicrobial activities against both phytopathogenic fungi and bacteria. Generally, the methanol extracts were more active than other extracts for S. officinalis and P. harmala, whereas for O. corniculata water extract showed more antimicrobial activity. Conclusion:   The study has been able to establish and document the important medicinal plants which can be used in the management of phytopathogens and infectious diseases in Iran

Occurrence of T-2 Toxin and Aflatoxin B1 in Cereals and Cereal Based Products: A Short Review

Mycotoxins as secondary metabolites produced by fungi are capable of causing disease and death in humans and animals. T-2 toxin is a member of trichothecene mycotoxin. Fusarium sporotrichioides, is the important T-2 toxin production. AFB1 is the strong potent natural carcinogen known, and is usually the major aflatoxin produced by Aspergillus species fungi. In this paper, we reviewed recent studies in different scientific databases including Science Direct, PubMed, Springer, Magiran and Google Scholar for T-2 toxin and Aflatoxin B1 contamination in cereals and cereal based products. According to the result of the study, Aflatoxin B1 and T-2 toxin have been found in cereals and cereal-based products in Iran and worldwide and ELISA and HPLC techniques in determining the range of toxins are mostly used

Occurrence of Zearalenone and Ochratoxin A in Cereals and Cereal Based Products

The contamination of cereals with toxic secondary metabolites of fungi, mycotoxins, is a permanent challenge in human health. These toxins are produced by a few fungi are mainly of the genera Fusarium, Aspergillus and Penicillium. Ochratoxin A is a nephrotoxic mycotoxin, which possesses carcinogenic, teratogenic, immunotoxic and possibly neurotoxic properties. Zearalenone is a non-steroidal estrogenic toxin, which has been involved in incidents of precocious pubertal changes. In this study, we reviewed recent researches in zearalenone and ochratoxin A contamination in cereals and cereal based product

The Effect of Culture Medium on Metabolic and Antibacterial Activities of Probiotic Bacteria

Background and Objectives: Probiotic bacteria is added directly to food components and it has beneficial effect on function and the health of organisms. The bifidogenic factors enter the colon where they contribute to an increase lactic acid bacteria population including Lactobacilli and Bifidobacteria and they inhibit enteric pathogenic bacterial growth. The aim of this study is to investigate the effect of culture medium on metabolic and antibacterial of probiotic bacteria.Methods: In this study, the probiotics bacterial and intestine pathogenic are to be used. Lactobacilli and Bifidobacterium were identified by plating samples on MRS medium, Gram Staining and standard biochemical methods. The effect of antagonistic probiotics was investigated in the presence of growth factor in the method well diffusion Ager on the Shigella flexneri (PTCC 1234), Escherichia coli (PTCC 1552), Salmonella typhi ( PTCC 1609) and the culture medium pH was measured.Results: The probiotics bacterial growth in MRS and lactose1%, sorbitol, raffinose, riboflavin were shown the effect antibacterial. The results of the study show the most antagonistic activity in commercial strain Lactobacillus acidophilus on Shigella flexneri and lower activity was in Lactobacillus casei (PTCC 1608), and Salmonella typhimurium (PTCC 1609), and also in Bbifidobacterium bifidum, it showed the most decrease pH value.Conclusion: According to the result of the study, adding growth factors to MRS medium base and lactose 1%, probiotic growth was increased and which also increased antagonistic activity

Antagonistic Activity of Probiotic Bacteria Isolated from Traditional Dairy Products against E. coli O157:H7

Background:    Probiotics are living microorganisms that have useful effects on health of digestive system when acquired in a defined dosage. E. coli O157:H7 is known as one of the most important agents of diarrhea in developing countries. Therefore, attention to the treatment of such gastrointestinal disease is essential. The aim of this study was to determine antagonistic activity of food born lactobacilli against E. coli O157:H7. Methods:     Lactobacilli were isolated from traditional dairy products (yogurt and buttermilk samples). Then, they were characterized using biochemical and molecular tests. Bifidobacterium bifidum PTCC 1644 was obtained from the microbial collection of Iranian Research Organization for Science and Technology in Lyophilized form. Similarly, E. coli O157:H7 PTCC12900 was obtained from faculty of veterinary medicine university of Tehran. The antagonistic activity of probiotics supernatants against E. coli O157:H7 was investigated using the disk diffusion agar, well diffusion agar and pour plate methods. Results:   The isolates were characterized as Lactobacillus plantarum and Lactobacillus fermentum. All isolates showed antagonistic activities against E. coli O157:H7 in all of the three methods, where the activity of L. plantarum and B. bidifum PTCC 1644 was greater than that of L. fermentum. Conclusion:   Metabolites produced by the probiotic bacteria are able to inhibit the growth of E. coli O157:H7. This can be an important solution for the prevention and treatment of E. coli O157:H7 infection and ultimately improve human health

The Prevalence of Gram-Negative Bacilli in the Environment and the Equipments: A Case Study in Hospitals of the East of Golestan Province, Iran

Background:  Nosocomial infections are considered as health issues that affect developed and poor countries. These infections can be transmitted to patients through hospital environment and equipments. The aim of this study was to evaluate the prevalence of Gram-negative bacilli in the environment and the equipments of hospitals in the East of Golestan province in 2015.  Methods:  In this study, 770 samples were collected using sterile swabs from the environment and equipments which were in use in different units of six teaching hospitals located in the East of Golestan province. The collected samples were then identified by standard biochemical tests.  Results:   Of the total samples, 249 samples (32.33%) were contaminated with Gram-negative bacilli with the most number of contaminations were Enterobacter aerogenes (37.75%) at the Department of Surgery (18.07%).  Among the medical equipments and surfaces, the highest level of contamination was observed in laryngoscope and its blades (10.44%), suctions (7.23%), and EKG sensors and monitoring connectors (7.23%). Telephone handset (5.22%) and patients’ bed (5.22%) had the highest rate of contamination with Gram-negative bacilli in the non-medical equipments.  Conclusion:  The results of the present study shows that Gram-negative bacilli contamination rates are considerable in hospitals in East of the Golestan province. Thus, hand washing, disinfecting, sterilizing medical equipment and generally compliance with the standards in this field are of great importance