Browsing by Author "Amin H.M."

Now showing 1 - 4 of 4

Biofilm formation in enterococci: Genotype-phenotype correlations and inhibition by vancomycin
(Nature Publishing Group, 2017) Hashem Y.A.; Amin H.M.; Essam T.M.; Yassin A.S.; Aziz R.K.; Department of Microbiology and Immunology; Faculty of Pharmacy; British University in Egypt (BUE); Shorouk City; Egypt; Department of Microbiology and Immunology; Faculty of Pharmacy; October University for Modern Sciences and Arts; 6 October City; Egypt; Department of Microbiology and Immunology; Faculty of Pharmacy; Cairo University; Cairo; Egypt
Enterococci are nosocomial pathogens that can form biofilms, which contribute to their virulence and antibiotic resistance. Although many genes involved in biofilm formation have been defined, their distribution among enterococci has not been comprehensively studied on a genome scale, and their diagnostic ability to predict biofilm phenotypes is not fully established. Here, we assessed the biofilm-forming ability of 90 enterococcal clinical isolates. Major patterns of virulence gene distribution in enterococcal genomes were identified, and the differentiating virulence genes were screened by polymerase chain reaction (PCR) in 31 of the clinical isolates. We found that detection of gelE in Enterococcus faecalis is not sufficient to predict gelatinase activity unless fsrAB, or fsrB alone, is PCR-positive (P = 0.0026 and 0.0012, respectively). We also found that agg is significantly enriched in isolates with medium and strong biofilm formation ability (P = 0.0026). Additionally, vancomycin, applied at sub minimal inhibitory concentrations, inhibited biofilm in four out of five strong biofilm-forming isolates. In conclusion, we suggest using agg and fsrB genes, together with the previously established gelE, for better prediction of biofilm strength and gelatinase activity, respectively. Future studies should explore the mechanism of biofilm inhibition by vancomycin and its possible use for antivirulence therapy. � 2017 The Author(s).
Modulation of laccase transcriptome during biodegradation of naphthalene by white rot fungus Pleurotus ostreatus
(Springer, 2019) Elhusseiny S.M.; Amin H.M.; Shebl R.I.; Department of Microbiology and Immunology; Faculty of Pharmacy; Ahram Canadian University (ACU); 4th Industrial Area; 6th of October City; Cairo; 12566; Egypt; Department of Microbiology and Immunology; Faculty of Pharmacy; Modern Sciences and Arts University (MSA); 6th of October City; Cairo; Egypt
Biodegradation of polycyclic aromatic hydrocarbons (PAHs) using Pleurotus ostreatus was investigated in the current study along with the expression levels of laccase genes involved in biodegradation under variable conditions. Biodegradation of PAHs (naphthalene, anthracene, and 1,10-phenanthroline) was detected spectrophotometrically. Recorded data revealed that biodegradation of the tested PAHs was time dependent. Elevated level of naphthalene biodegradation (86.47%) was observed compared to anthracene (27.87%) and 1,10-phenanthroline (24.51%) within 3�days post incubation. Naphthalene was completely degraded within 5�days. Further incubation enhanced the biodegradation of both anthracene and 1,10-phenanthroline until reaches 93.69% and 92.00% biodegradation of the initial concentration within an incubation period of 11 and 14�days, respectively. Naphthalene was selected as a PAH model. HPLC and thin layer chromatography of naphthalene biodegradation products at time intervals proposed that naphthalene was first degraded to ?- and ?-naphthol which was further metabolized to salicylic and benzoic acid. The metabolic pathway of naphthalene degradation by this fungus was elucidated based on the detected metabolites. The expression profile of six laccase isomers was evaluated using real-time PCR. The transcriptome of the fungal laccase isomers recorded higher levels of transcription under optimized fermentation conditions especially in presence of both naphthalene and Tween 80. The accumulation of such useful metabolites from the biodegradation of PAH pollutants recommended white rot fungus as a potential candidate for production of platform chemicals from PAH wastes. � 2018, Springer Nature Switzerland AG.
The preservative efficacy of Licorice and Rosemary combination in cream formula
(Scholars Research Library, 2014) Assar N.H.; Hamouda H.M.; Mohamed G.S.; Amin H.M.; Department of Microbiology; National organization for Drug Control and Research; M.S.A University; Egypt; Department of Microbiology; Faculty of Pharmacy; M.S.A University; Egypt
Based on our previous results, which proved that each of G. glabra and R. officinalis extracts potentiate the antibacterial effect of the other aganist MRSA when combined together at their sub-MIC. We thought to investigate the capacity of Glycyrrhiza glabra(Licorice) and Rosmarinus officinalis (Rosemary) extracts to act as preservatives for topical formulations, which in our knowledge is the first to be used together. Two Oil/Water(O/W )cream were formulated : using methyl paraben, a common used preservative (MP) and the combination between Licorice and Rosemary (LR) as preservatives, were tested for their Primary skin irritation on Laboratory experimental animals which proved that they were devoid of any primary skin irritation, erythema, or edema even after 48 h of application, and by challenging them with microbial indicators: Bacterial; (Escherichia Coli 25922, Pseudomonas aeruginosa 27853 and Staphylococcus aureus 29737), Yeast; (Candida albicans10231), and fungi; (Aspergillus niger 1015), revealed that the concentration of each test microorganisms decreased during the test period.
Synergistic antibacterial effect of Glycyrrhiza glabra and Rosmarinus officinalis against MRSA isolated from Egypt
(Bentham Science Publishers B.V., 2015) Assar N.H.; Hamouda H.M.; Mohamed G.S.; Amin H.M.; Department of Microbiology; National Organization for Drug Control and Research; Egypt; Faculty of Pharmacy; Cairo University; Egypt; Department of Microbiology; M. S. A University; Egypt; Department of Microbiology and Immunology; King Abdul-Aziz University; Saudi Arabia
192 Staphylococcus samples were isolated from patients in Egyptian hospitals and 112 were identified as Staphylococcus aureus using conventional methods based on morphological and biochemical characteristics. Sensitivity of isolates to a range of antibiotics was also tested by disc diffusion method, which revealed that 82% of isolates were MRSA isolates. Methicillin resistance was confirmed using PCR-based molecular approach, 8 isolates were harboured mecA gene and 4 isolates were Borderline S. aureus (BORSA). MICs of different antibiotic classes were determined; results were varied to different antibiotics, where Penicillin and Ampicillin MICs varied from resistant to borderline resistant isolates (512,62?g/ml). Cinnamomum cassia, Syzygium aromaticum, Glycyrrhiza glabra, Rosmarinus officinalis and Salvia officinalis plant extracts were tested to examine their antibacterial activity against MRSA isolates. MIC of tested plant extracts was evaluated by agar dilution method. Diethyl ether extracts of G. glabra, R. officinalis and S. officinalis showed the lowest MICs values (0.05, 0.39, 0.195mg/ml respectively). Investigation of possible synergistic effect upon combination between plant extracts with the lowest MICs values was evaluated by a checkerboard titration assay. Combination between diethyl ether extracts of G. glabra and R. officinalis at conc. 0.0125 and 0.0975 mg/ml respectively showed synergistic effect on MRSA isolates and standard strain. Both extracts shown antibacterial effects on MRSA cells by shrinkage of the protoplasts and disruption of the cytoplasmic membrane evidenced by protein analysis and Microscopic examination of cells pre and post treatment by TEM .These results suggest that these extracts might be used as a promising antibacterial agent.