Browsing by Author "Abd El-Rahman O.A."

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    Antimicrobial activities against biofilm formed by Proteus mirabilis isolates from wound and urinary tract infections
    (2012) Wasfi R.; Abd El-Rahman O.A.; Mansour L.E.; Hanora A.S.; Hashem A.M.; Ashour M.S.; Department of Microbiology; Faculty of Pharmacy; University for Modern Sciences and Arts; Giza; Egypt; Department of Microbiology and Immunology; Faculty of Pharmacy; Al-Azhar University; Cairo; Egypt; Department of Microbiology and Immunology; Faculty of Pharmacy; Suez Canal University; Ismailia; Egypt; Department of Microbiology and Immunology; Faculty of Pharmacy; Cairo University; Cairo; Egypt
    Background: Bacterial species are capable of living as biofilm and/or planktonic forms. There is increasing evidence for the role of bacterial biofilm in various wound and urinary tract infections (UTIs). The aim of the present study was to evaluate the ability of the bacteria, isolated from urinary tract infections (UTIs) and wound infections, to form biofilm and correlate the role of biofilm with their antimicrobial resistance. Materials and Methods: All the isolated bacteria were screened for their ability to form biofilm using the microtitre plate method. Results: Wound isolates of Staphylococcus aureus and Enterobacter sp. had more biofilm forming capacity than the UTI isolates. Proteus mirabilis isolates were among the strongest biofilm forming bacteria and were chosen for antimicrobial study. In sub-MIC concentrations of antimicrobial agents used, ciprofloxacin was found to be the most effective in decreasing biofilm formation. On the other hand, ceftriaxone and ciprofloxacin were effective in partial removal of preformed biofilm biomass. Conclusion: Ciprofloxacin was more effective in killing bacterial cells especially at high antimicrobial concentrations that could be reached in urine levels and can be used in impregenating catheters.
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    Probiotic Lactobacillus sp. inhibit growth, biofilm formation and gene expression of caries-inducing Streptococcus mutans
    (Blackwell Publishing Inc., 2018) Wasfi R.; Abd El-Rahman O.A.; Zafer M.M.; Ashour H.M.; Department of Microbiology and Immunology; Faculty of Pharmacy; October University for Modern Sciences and Arts (MSA); Giza; Egypt; Department of Microbiology and Immunology; Faculty of Pharmacy; Al-Azhar University (Girls); Cairo; Egypt; Department of Microbiology and Immunology; Faculty of Pharmacy; Ahram Canadian University (ACU); Giza; Egypt; Department of Biological Sciences; College of Arts and Sciences; University of South Florida St. Petersburg; St. Petersburg; FL; United States; Department of Microbiology and Immunology; Faculty of Pharmacy; Cairo University; Cairo; Egypt
    Streptococcus mutans contributes significantly to dental caries, which arises from homoeostasic imbalance between host and microbiota. We hypothesized that Lactobacillus sp. inhibits growth, biofilm formation and gene expression of Streptococcus mutans. Antibacterial (agar diffusion method) and antibiofilm (crystal violet assay) characteristics of probiotic Lactobacillus sp. against Streptococcus mutans (ATCC 25175) were evaluated. We investigated whether Lactobacillus casei (ATCC 393), Lactobacillus reuteri (ATCC 23272), Lactobacillus plantarum (ATCC 14917) or Lactobacillus salivarius (ATCC 11741) inhibit expression of Streptococcus mutans genes involved in biofilm formation, quorum sensing or stress survival using quantitative real-time polymerase chain reaction (qPCR). Growth changes (OD600) in the presence of pH-neutralized, catalase-treated or trypsin-treated Lactobacillus sp. supernatants were assessed to identify roles of organic acids, peroxides and bacteriocin. Susceptibility testing indicated antibacterial (pH-dependent) and antibiofilm activities of Lactobacillus sp. against Streptococcus mutans. Scanning electron microscopy revealed reduction in microcolony formation and exopolysaccharide structural changes. Of the oral normal flora, L.salivarius exhibited the highest antibiofilm and peroxide-dependent antimicrobial activities. All biofilm-forming cells treated with Lactobacillus sp. supernatants showed reduced expression of genes involved in exopolysaccharide production, acid tolerance and quorum sensing. Thus, Lactobacillus sp. can inhibit tooth decay by limiting growth and virulence properties of Streptococcus mutans. � 2018 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.