[Antibacterial effects of Rosmarinus officinalis on methicillin - resistant Staphylococcus aureus isolated from patients and foods]

Methicillin-resistant Staphylcoccus aureus [MRSA] is considered a major problem in the world. This strain colonizes nose and causes increased incidence of nosocomial infections, mortality and morbidity. Rosemary [Rosmarinus officinalis] is a herbal medicine widely used all over the world. The aim of this study was to evaluate the in vitro antimicrobial activity of rosemary essence on MRSA isolated from patients and food. 200 strains of MRSA, 100 from patients and 100 from food samples, were collected and analyzed in Tehran, during the last year. 28 MRSA strains and multi drug resistant [MDR] strains were isolated. The antimicrobial activity of the rosemary essence against different isolates of the microorganism was evaluated by disk diffusion and macro broth dilution methods. MRSA isolates belonged to 25% and 60% of food and clinical samples, respectively. The results showed effective and similar antimicrobial activity of Rosmarinus officinalis on broth clinical and food samples with an inhibition zone of 20mm in diameter. The minimum inhibitory concentration [MIC] and minimum bactericidal concentration [MBC] in our study were 1.40 mg/ml and 2.81 mg/ml, respectively. Overuse of antibiotics has led to extensive bacterial resistance to antibiotics, which demonstrates the need for use of new antimicrobial agents. Considering increasing prevalence of MRSA strains and the beneficial effect of rosemary essence on these strains, this essence can be recommended for the treatment of MRSA infections

[ evaluation of probiotic effect of L.acidophilus on the immune responses in BALB/C mice against transplanted tumor derived from breast tissue]

Antitumor effect of lactic acid bacteria have been shown in many studies, this effect maybe due to the immunomodulatory properties of these bacteria. In present work we have studied the effect of Lactobacillus [L] acidophilus on the immune responses of BALB/c mice against transplanted tumor derived from breast tissue. 6-8 week-old in-bred BALB/c mice, each weighing 25-30 g, were used. The mice were divided into two groups each consisted of 9 mice as test and control groups. The L.acidophilus ATCC4356 strain was used in this study. It was inoculated in MRS agar and cultivated overnight under anaerobic conditions then collected and resuspended in PBS. After preparation of proper amount of this suspension it was orally [2.7 x 10[8] CFU/ml] administered to the mice with a gastric feeding 2 weeks before tumor transplantation and 3 weeks after that, with 3 days break and 7 days administration. The control mice received an equal volume of PBS during the study. Results of the present work showed that L. acidophilus can increase the production of immunomodulatory cytokine IL-12 and decrease the TGF-alpha which can suppress immune response. Moreover, the growth rate of tumor in group which received L. acidophilus were decreased and the results of delayed type hypersensitivity [DTH] of this group in 48h were better than control group. The results of our study suggest that daily use of L. acidophilus can regulate immune response with Th1 dominance and may be helpful for cancer immunotherapy, but further studies are needed to investigate the other mechanisms of this effect

[ probiotic effects of Lactobacillus casei in BALB/c mice on the Tumor growth rate bearing breast cancer]

Antitumor effect of lactic acid bacteria [LAB] have been shown in many studies, this effect maybe as a result of immunomodulatory properties of these bacteria. In present work, we have studied the effect of Lactobacillus casei on the tumour growth rate in BALB/c mices bearing breast cancer. 6-8 week-old In-bred BALB/c mice, each weighing 25-30 g, were used. There are two experimental group consisted of 9 mices that they were used as controls in each assay. The L.casei ATCCT 39392 strain used in this study was inoculated in MRS broth and cultivated for a day at 37 °C under anaerobic conditions, collected by centrifugation and resuspend in PBS. After preparation of proper amount of these suspension it was orally administered to the mice with a gastric feeding, Control mice received an equal volume of PBS in duration of study. Results of this study showed that oral administration of L.casei can inhibit the tumour growth and increased the local inflammation in DTH assay as a result of increase in immune responses efficiency. In conclusion oral administration of Lactobacillus casei may regulate immune responses skewed Th1 balance and maybe helpful for cancer immunotherapy, but further studies is needed to investigate the other mechanisms of this effect

[Prevalence and antibiotic resistance pattern of Staphylococcus aureus strains isolated from food stuff]

Staphylococcus aureus is considered to be one of the leading causes of food-borne illnesses. Foodstuff contamination may occur directly from contaminated food-producing animals or may result from poor hygiene during food production processes, or the retail and storage of foods, since humans may carry the microorganism. The number of S. aureus strains that exhibits antimicrobial-resistance properties has increased, together with the potential risk of transmitting the same properties to the human micro flora via food or inducing infections hard to be treated. The aim of this study was to evaluate the occurrence of S. aureus in various food samples and determination of antibiotic resistance pattern in this isolates. A total of 1047 food samples were analysed from July 2006 to December 2007. To determine the presence of S.aureus, the samples were analysed according to the guidelines of Iran standard instructions [No. 1194]. S.aureus isolates were tested for susceptibility to a panel of 11 antimicrobics using the agar disc diffusion method on Muller-Hinton agar. Of 1047 samples analysed 100 [9.5%] were contaminated with S.aureus. Among these contaminated samples, 31% showed antimicrobial resistance properties to at least one of the antibiotic tested and 15 antibiotypes were determined. According to the observed prevalence of S.aureus strains in food samples and their antibiotic resistance pattern, more attention should be paid in foodstuff industry to prevent contamination and transmission of resistant strains