Mohamed Refai أ.د. محمد كمال رفاعي

{Gelatin contamination is of great concern from economic and public health point of view. In this study, bacterial contamination during different stages of gelatin manufacturing process was examined. One hundred and fifty four isolates were obtained from different stages of gelatin production process. Wet noodles samples acquired the highest percentage of bacterial isolates (14.93%). Majority of the bacterial isolates were classified as Gram-positive bacilli (79.8%). 51.3% of isolates showed moderate gelatinase activity. The most potent gelatinase producing isolate was identified as Bacillus cereus based on biochemical and 16S rRNA sequence analyses. Fluoroquinolones were the most effective antibiotics against bacterial isolates with the highest sensitivity rate (94.78%). Cinnamon oil exhibits the highest sensitivity rate (97.6%) and low MIC values (0.195 mu l/ml). GC/MC analyses revealed that monoterpenes were the predominant components of the essential oils. The main constituent of cinnamon oil was cinnamaldehyde (63.69%). Gelatinase was purified by ion exchange and size exclusion chromatography. Zymography and SDS-PAGE analysis estimated that the purified enzyme is similar to 100 KDa molecular size.}

{A new class of diphenylurea was identified as a novel antibacterial scaffold with an antibacterial spectrum that includes highly resistant staphylococcal isolates, namely methicillin-and vancomycin-resistant Staphylococcus aureus (MRSA & VRSA). Starting with a lead compound 3 that carries an aminoguanidine functionality from one side and a n-butyl moiety on the other ring, several analogues were prepared. Considering the pharmacokinetic parameters as a key factor in structural optimization, the structureactivity-relationships (SARs) at the lipophilic side chain were rigorously examined leading to the discovery of the cycloheptyloxyl analogue 21n as a potential drug-candidate. This compound has several notable advantages over vancomycin and linezolid including rapid killing kinetics against MRSA and the ability to target and reduce the burden of MRSA harboring inside immune cells (macrophages). Furthermore, the potent anti-MRSA activity of 21n was confirmed in vivo using a Caenorhabditis elegans animal model. The present study provides a foundation for further development of diphenylurea compounds as potential therapeutic agents to address the burgeoning challenge of bacterial resistance to antibiotics. (C) 2017 Elsevier Masson SAS. All rights reserved.}