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ABSTRACT: Introduction & Objective:Dental caries is perhaps the most common bacterial infections in humans and Streptococcus Mutans is one of the most important factors in dental caries. Research has shown that some kind foods have an inhibitory effect on cariogenic factors of Mutans streptococci. The aim of this study was to investigate the effect of date extract on growth of Streptococcus Mutans. Methods & Materials: This experimental study was down at faculty of medicine, Yasuj university of medical sciences with collaborative of microbiology department of Shiraz university of medical sciences in 2005. In an In-vitro study, effect of date extract on growth of Mutans Streptococci was surveyed .After collecting of Streptococcus Mutans from dental caries those were cultured in different medium of date fruit, extract of date fruit and syrup of date with different concentrations. Results: Following 24 hours, Streptococcus mutans was grown in less concentration of date mediums and its grown was inhibited in more concentrations. Conclusion: With respect of inhibitory effect of date extract on growth of Streptococcus mutans,it might be introduced that date as a source of food has a preventive effect on dental caries.

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ABSTRACT Introduction & Objective: Pseudomonas aeruginosa is a gram negative bacterial. This bacterium is resistant to many antibiotics and chemical disinfectants. Pseudomonas aeruginosa is an opportunistic bacteria and caused infection in skin, external ear, upper respiratory tract, large intestine and is an important bacteria in nosocomial infections. It causes acute infection in burn disease. This bacterium can produce exotoxin A and effect on elongation factor II and can stop protein synthesis. The aim of this study was to evaluate the effect of exotoxin A on mice WBC and comparison of the results with human WBC that contaminated with Pseudomonas aeruginosa. Materials & Methods: This is an experimental study which was conducted in 1384 on burn disease patients referred to Shiraz Ghotbodin hospital. Sample that contaminated with PA was taken from these patients for WBC count and WBC differentiation. Sample was also taken from 100 burn patients without infection (50 male and 50 female). Toxigenic strain of PA103 was cultured on liquid media and used for purification of exotoxin A. This sample was injected to 50 mice (I.V) and after different incubation time, WBC was counted. Ten normal mice was used as control. Collected data analyzed by SPSS. Results: WBC count decreased in mice that received Pseudomonas aeruginosa exotoxin A in comparison with normal mice (P<0.05). WBC count was significantly decreased in burn patients in comparison with normal individuals (P<0.029) and most decrease was belonged to PMN. Conclusion: The results demonstrated that Pseudomonas aeruginosa that produce exotoxin induce WBC decrease in burn disease and also in mice that contaminated with exotoxin of this bacteria. It can be concluded that bacterial infection in burn patients is toxigenic strain of PA that produce exotoxin A.