عبدالله اردبیلی

Some yeasts, such as Z. bisporis and P. occidentalis, still need further study to determine their functional characteristics and how to use them in the food and pharmaceutical industries. The purpose of this study is the investigation of the functional and antioxidant properties of Z. bisporis and P.occidentalis isolated from Kombucha.

for this purpose, antioxidant capacity by 1,1-diphenyl-2-picrylhydrazyl radical method (DPPH) and functional properties (survival under simulated conditions of the gastrointestinal system, hydrophobicity, auto aggregation and antioxidant properties, antimicrobial activity against food-borne pathogenic bacteria such as Staphylococcus aureus, Yersinia enterocolitica, Bacillus cereus and Escherichia coli was investigated by spot method.

The results of this research showed that Z.bisporis and P.occidentalis have excellent antioxidant activity of about 67.67 and 69.18 percent, auto aggregation capacity of about 92.44 and 87.30 percent. After 24 hours and high hydrophobicity activity has provided about 87.51 and 86.127 percent. Also, the survival percentage of these isolates under the simulated conditions of the gastric juice was about 54.87 and 88.87%, under the simulated conditions of the duodenum, it was 97.09 and 94.40%. Z. bisporis studied in this test had antimicrobial activity against Yersinia enterocolitica, but did not show any activity against the tested microorganisms.

According to the obtained results, it is suggested to use more of these strains as a natural source of antioxidant and probiotic supplement in the production of food and pharmaceutical products after completing additional tests.

Prevalence of methicillin resistant Staphylococcus aureus (MRSA) strains is one of the most important health care problems and life-threatening in worldwide. The methicillin resistant S. aureus strains producing biofilm and slime have potential to colonize and transmit. The present study was conducted to detect intercellular adhesion (ica) genes involved in biofilm and slime formation in clinical isolates of methicillin resistant S. aureus harboring mecA gene.
In this cross-sectional study, a total of 85 bacterial isolates suspected to S. aureus were prepared from clinical samples. The antibiotic susceptibility testing of bacteria to the penicillin, gentamicin, oxacillin, ciprofloxacin, ofloxacin and vancomycin was carried out based on disk diffusion agar method. Biofilm and slime formation of bacteria were examined by tissue culture polystyrene plate (TCP) and Congo red agar (CRA). The presence and frequency of ­icaA, icaD and mecA genes were detected by multiplex PCR.
45 out of 85 (52.94%) S. aureus isolates were resistant to the methicillin. All of methicillin resistant S. aureus were able to produce biofilm and slime. Consumedly surface hydrophobicity was seen in 55.55% and 100% of strains producing strong biofilm and slime, respectively. The ­icaA, icaD and mecA genes were present in all biofilm and slime producing isolates.
Our results showed that the all methicillin resistant S. aureus isolates with some abilities, including polysaccharide intercellular adhesion, bacterial attachment, biofilm and slime production were positive for icaA and icaD genes.

In the recent years, Acinetobacter baumannii has emerged as a major nosocomial pathogen, particularly in burn and intensive care units. Based on the several studies showing the seasonal increase in incidence of A. baumannii infections in the summer months, we conduct a study to determine the incidence of wound infections in patients admitted to a burn hospital over a one-year period. 298 burned patients hospitalized in Motahari burn care center were investigated for A. baumannii wound infection during the one-year period.The correlation between infection rates and weather conditions in each month was analyzed statistically using SPSS software. The wound infection rate due to A. baumannii was 25.5%. Significant difference was found statistically between the first and second six-month of study period in the infection rate. In addition, the highest rate of Acinetobacter infection was between late June and late September. Due to higher prevalence of A. baumannii strains in warm months of the year, it is necessary to implement essential measures for decrease infections caused by such bacteria and improve health care quality in burned patients.

Due to increasing antibiotic resistance, it is important to identify the antimicrobial activity of herbs. This experimental study aimed to evaluate the antimicrobial activity of herbal extracts of common hop (Humulus lupulus) and oak (Quercus castaneifolia) against several microbial standard strains. The alcoholic and aqueous extracts of H. lupulus and Q. castaneifolia were extracted. The inhibitory effects of herbal extracts were evaluated against the microbial standard strains (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans) by both agar diffusion and macrobroth dilution methods. In the agar diffusion method, concentrations of extracts were 125, 250, 500 and 1000 mg/ml. In order to determine the MIC, serial dilutions were prepared with a range from 1 to 512 mg/ml. Alcoholic extract of both hop and oak showed higher inhibitory effect against microbial standard strains, compared to the aqueous extract. Staphylococcus aureus ATCC 29213 and Candida albicans ATCC 76615 showed higher susceptibility to both alcoholic and aqueous extracts compared to Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. Statistically significant difference was found on the MIC of alcoholic and aqueous extracts (p< 0.05). This study revealed the considerable inhibitory effects of herbal hop and oak extracts on the various microorganisms, including bacteria and fungi. Although more research is needed in this field, they can be used as new antimicrobials in medicine.

Listeria monocytogenes is a facultative intracellular pathogen that causes listeriosis which has extensive clinical manifestations. Infections with L. monocytogenes are a serious threat to immunocompromised persons. The aim of this study was to determine the frequency of L. monocytogenes strains recovered from clinical and non-clinical samples using phenotypic methods and confirmed by PCR. In this study, 617 specimens were analyzed. All specimens were cultured in the specific PALCAM agar. Colonies were initially identified by routine biochemical tests. Finally, PCR assays using primers specific for inlA gene were performed. In all, 46 (8.2%) L. monocytogenes isolates were recovered from 617 specimens. Fourteen (8.2%) strains, including 4 (7.5%), 2 (5.7%), 5 (14.2%) and 3 (8.5%) isolates were obtained from placental tissue, urine, vaginal and rectal swabs, respectively. In addition, 9 (7.4%) strains of L. monocytogenes which were isolated from 107 different dairy products originated from cheese 5 (7.1%), cream 2 (10%) and kashk 2 (11.7%), respectively. Among 11 (5.2%) strains isolated from 210 different meat products, 5 (5.5%), 4 (7.2%) and 2 (3%) strains belonged to sausage, meat and poultry extracts, respectively. Finally, 12 (9.2%) Listeria strains were recovered from 130 animal specimens that included 6 (10%), 4 (8%) and 2 (10%) strains from goat, sheep and cattle, respectively. Furthermore, all Listeria isolates (100%) were found to be carriers of inlA gene in PCR assay. The present study showed that the clinical and non-clinical specimens were contaminated with L. monocytogenes. So, it seems necessary to use a simple and standard technique such as PCR for rapid detection of this organism from various sources.

Acinetobacter baumannii is an important human pathogen that has been a focus of attention in recent years. These bacteria are a leading cause of therapeutic resistant nosocomial infections especially in burned or hospitalized patients in intensive care Units. The aim of this study was to isolate the Acinetobacter baumannii species from the wounds of burned patients and to determine antimicrobial resistance pattern of these bacteria for selection of appropriate antibiotics. Samples were collected from patients and transferred to the laboratory under standard conditions. Bacteria were isolated and purified by conventional culture methods. Identification of bacterial species was performed by standard biochemical tests. The isolates that were identified as Acinetobacter baumannii were subsequently tested for antibiotic resistance by the disk diffusion agar method for 17 different antibiotics. The tests were carried out on Muller Hinton agar (MHA) plates and incubated at 35˚C for 18 hrs. The minimum inhibition concentrations were determined for 5 common therapeutic antibiotics. Out of the 65 clinical Acinetobacter baumannii isolates collected، 61 (94%) were multi drug resistant (MDR). Ceftazidime and aztronam (98%) were the most effective antibiotics against Acinetobacter baumannii. To determine the MIC، the highest levels of antibiotic resistance were seen against ceftazidime، cefepime، and ciprofloxacin. Our results confirm the high prevalence of Acinetobacter baumannii resistant isolates and the ensuing therapeutic problems in Iran. Determination of the resistance patterns of these bacteria according to MIC is necessary، and it can be especially helpful in treatment of burned patients.