Ahmed Abdelaziz | Tanta University (original) (raw)

Papers by Ahmed Abdelaziz

Journal of Advanced Medical and Pharmaceutical Research, 2020

Since penicillin was discovered by Sir Alexander Fleming in 1928, antibiotics have been used in m... more Since penicillin was discovered by Sir Alexander Fleming in 1928, antibiotics have been used in medicine to treat different infections and combat pathogenic microorganisms. Nevertheless, with their increasing and massive use, the progress of resistance has become more predominant and many bacteria have developed resistance to multiple classes of antibacterial agents through genetic exchange mechanisms. Consequently, the use of antibiotics is now under threat. Antibiotic resistance poses a worldwide hazard to both human and animal health and it has become an important public health concern in the 21 st century. This review aims to survey some mechanisms of antibiotic resistance. Furthermore, some novel approaches like the use of nanoparticle-based antimicrobial drug delivery, fecal microbiota transfer, antimicrobial peptides, antibiotic adjuvants, antisense antimicrobials, phage therapy, antivirulence strategies, host oriented therapy, synthesis of new antimicrobials and extraction of antimicrobials from a natural source like plants are identified and discussed in an attempt to combat and fight against bacterial resistance.

MicroRNAs regulate the expression of many genes and subsequently control various cellular process... more MicroRNAs regulate the expression of many genes and subsequently control various cellular processes, such as the immune response to viral infections mediated by type I interferon (IFN). In this study, the expression pattern of two interferon-related microRNAs, miR-146a and miR-155, was examined in healthy and HCV-genotype-4-infected peripheral blood mononuclear cells (PBMCs) using qRT-PCR. In contrast to other viral infections, the expression pattern was similar in both healthy and infected PBMCs. This could be attributed to attenuation of IFN pathway by HCV, which was assessed by investigating the expression of MxA, an interferon-stimulated gene, that showed lower expression in HCV-infected PBMCs. To determine the site of interference of HCV in the IFN pathway, expression of both microRNAs was examined following stimulation of PBMCs with IFN-α2a, an activator of the JAK/STAT pathway as well as with imiquimod, a toll-like receptor-7 (TLR-7) agonist that promotes interferon release. IFN stimulation induced the expression of miR-146a and miR-155 in HCV-infected and healthy PBMCs. Stimulation with imiquimod led to a down-regulation of both microRNAs in infected PBMCs, while it increased their expression in healthy PBMCs, indicating that HCV might interfere with miR-146a and miR-155 expression at sites upstream of interferon release, specifically in the TLR-7 pathway. The pattern of expression of both miR-146a and miR-155 was very similar with a strong positive correlation, but showed no correlation to the patients' clinical or histopathological parameters or response to treatment. In conclusion, HCV infection might repress the induction of miR-146a and miR-155 by interfering with TLR-7 signaling.

Epidemiological relationships were investigated between 40 methicillin-resistant Staphylococcus a... more Epidemiological relationships were investigated between 40 methicillin-resistant Staphylococcus aureus (MRSA) strains with decreased glycopeptide susceptibility isolated from November 1998 to March 1999 from 39 patients (17 infected and 22 colonized patients) in nine wards of the Broussais Hospital, Paris, France. Reduced glycopeptide susceptibility was readily detected on brain heart infusion (BHI) agar containing 6 g of teicoplanin per ml and on gradient plates, but not by the standard disk diffusion method. The MICs of vancomycin and teicoplanin, determined on BHI agar, were 4 and 8 to 32 g/ml, respectively (standard antibiotic dilution), and 4 to 8 and 8 to 32 g/ml, respectively (E-test). All strains were resistant to macrolides, aminoglycosides, tetracycline, rifampin, sulfonamides, and pefloxacin, showed reduced susceptibility to fusidic acid and fosfomycin, and were susceptible to trimethoprim and chloramphenicol. Pulsed-field gel electrophoresis and lysotyping revealed that a multidrug-resistant MRSA clone with decreased susceptibility to glycopeptides has been discretely endemic since at least 1996 in our institution, where it was responsible for an outbreak in November and December 1998.

African journal of microbiology research

Background and objectives: Plasmids have been known to play a major role

Pakistan Journal of Biological Sciences

African journal of microbiology research

Published data concerning correlation between virulence factors and resistance markers is relativ... more Published data concerning correlation between virulence factors and resistance markers is relatively scarce. The aim of this study was to determine the relationship between antibiotic resistance, gelatinase production and pheromone response in the Enterococcus faecalis pathogens isolated from Egypt. Out of the 19 E. faecalis clinical isolates, 5 were able to produce gelatinase enzyme. These virulent isolates were multidrug resistant and showed high level vancomycin resistance. They were tested for mating ability. They cotransfered pheromone response genes together with vancomycin resistance determinants and gelatinase production to sensitive recipient strains. The gel E gene was detected in all donor isolates and their corresponding transconjugants phenotypically and genotypically. The PCR amplicons of a heavy gelatinase producing isolate and its transconjugants were subjected to sequencing. Significant homology was detected with OG1RF strain following sequence search with a GenBank...

Journal of Pharmacy and Pharmacology, 1990

Brazilian Journal of Microbiology, 2012

African journal of microbiology research

Published data concerning correlation between virulence factors and resistance markers is relativ... more Published data concerning correlation between virulence factors and resistance markers is relatively scarce. The aim of this study was to determine the relationship between antibiotic resistance, gelatinase production and pheromone response in the Enterococcus faecalis pathogens isolated from Egypt. Out of the 19 E. faecalis clinical isolates, 5 were able to produce gelatinase enzyme. These virulent isolates were multidrug resistant and showed high level vancomycin resistance. They were tested for mating ability. They cotransfered pheromone response genes together with vancomycin resistance determinants and gelatinase production to sensitive recipient strains. The gel E gene was detected in all donor isolates and their corresponding transconjugants phenotypically and genotypically. The PCR amplicons of a heavy gelatinase producing isolate and its transconjugants were subjected to sequencing. Significant homology was detected with OG1RF strain following sequence search with a GenBank...

Zentralblatt für Bakteriologie, Mikrobiologie und Hygiene. Serie B, Umwelthygiene, Krankenhaushygiene, Arbeitshygiene, präventive Medizin, 1989

Fifty items of Al-Kohl collected from northern Jordanian provinces representing: 20 unopened read... more Fifty items of Al-Kohl collected from northern Jordanian provinces representing: 20 unopened ready to use samples purchased from retail outlets, 20 in-use samples obtained from ladies of different socioeconomic standards and 10 samples of the original stones (used for Al-Kohl preparation) were examined for their microbial contents. Ready to use and in-use samples were much more contaminated than the original stones. On sterility testing, more than 85% of the unused and in-use samples were contaminated with bacteria and or fungi comparing to 50% of the original stone samples. Quantitatively, 90% of the original stones contained less than 100 bacterial or fungal cells/g and the other remaining 10% were in the range of 10(2)-10(3) cfu/g either for bacterial or fungal counts. The level and distribution of the viable microbial counts in unused and in-use samples were comparable and much higher than original stones. More than 70% and 20% of those items contained more than 100 cfu/g of bac...

Immunological Investigations, 2015

A group of 11 medicinal plants, including Lavandula pubescens, Trigonella foenugricium, Salsola s... more A group of 11 medicinal plants, including Lavandula pubescens, Trigonella foenugricium, Salsola schweinforthi, Calligonum comosum, Silene succulenta, Silene villosa, Bogonvillea glabra, Cakile maritime, Gomphrene celesoids, Mirabilis jalaba, and Silene nocturna growing in Egypt, were extracted and examined for their immunomodulatory and antioxidant activities. RAW 264.7 cells were recruited to investigate the immunomodulatory effect through multiple parameters analysis. First, the proliferation index of macrophages cells was evaluated revealing that Trigonella foenugricium, Silene succulenta and Silene villosa have a significant cytotoxic effect on RAW cells. Interestingly, we observed enhancement of macrophages phagocytic function of by all extracts except Cakile maritime, Gomphrena celosioides and Silene nocturna. Afterwards, macrophages were challenged by incubation with LPS and the effect of various extracts on inflammatory responses was investigated; the generation of NO from activated macrophage was substantially suppressed by 7 extracts namely, Trigonella foenugricium, Calligonum comosum, Silene succulenta, Bougainvillea glabra, Mirabilis jalaba, Gomphrena celosioides and Silene nocturna. TNF-a was decreased by percentage range from 3.8 to 85.8% and Trigonella foenugricium extract showed the highest inhibition of TNF-a release. All extracts except Trigonella foenugricium, Salsola schweinforthi, Silene succulenta and Mirabilis jalaba significantly inhibited COX-2 production from stimulated macrophage. Moreover, evaluating the potential antioxidant activity of these extracts showed that Trigonella foenugricium, Salsola schweinforthi, Calligonum comosum, Bogonvillea glabra and Mirabilis jalaba exhibited some antioxidant activities. Taken together, our results suggest that some of these extracts may have a considerable antinflammatory and antioxidant effects and may be a potential therapeutic choice in the treatment of inflammatory diseases.

Pharmaceutical Biology, 1990

... Cytotoxicity, Mutagenicity and Antimicrobial Activity of Forty Jordanian Medicinal Plants Ahm... more ... Cytotoxicity, Mutagenicity and Antimicrobial Activity of Forty Jordanian Medicinal Plants Ahmad S. ALKDFAHI*, Ahmad ABDELAZIZ*, Ibrahim MAHMOUD*, Mustafa ABUIRJIE*, Abdelrahim HUNAITI** AND Ahmad EL-OQLA** ABSTRACT ...

Immunopharmacology and Immunotoxicology, 2011

A group of medicinal plant including Silene (Silene nocturna), Black seed (Nigella sativa) and Ch... more A group of medicinal plant including Silene (Silene nocturna), Black seed (Nigella sativa) and Chamomile (Matricaria chamomilla) growing in Egypt were examined for their immunomodulatory effect in Balb/c mice. Treatment (intraperitoneal injection) with five doses of methanolic extract for each plant was found to enhance the total white blood cells count (up to 1.2 × 10(4) cells/mm(3)). Bone marrow cellularity also increased significantly (P < 0.01) after the administration of the extract of each of three test plants. Furthermore, spleen weight of the treated groups was significantly increased (P < 0.01). Two groups of mice were immunosuppressed with cyclophosphamide, the one which pretreated with the plants extracts significantly (P < 0.01) restored their resistance against lethal infection with the predominately granulocyte-dependant Candida albicans. These results confirm the immunomodulatory activity of Silene, Black seed, and Chamomile extracts and may have therapeutical implications in prophylactic treatment of opportunistic infections and as supportive treatment in oncogenic cases.

Objective: The aim was to optimize norfloxacin niosomes for enhanced antibacterial activity and r... more Objective: The aim was to optimize norfloxacin niosomes for enhanced antibacterial activity and reduced bacterial resistance. Methods: Pseudomonas aeruginosa, a biofilm forming bacterium, was used as the test organism. Different norfloxacin niosomes were evaluated in vitro and in vivo, respectively, for antibacterial activity compared with aqueous drug solution. The influence of norfloxacin niosomes on biofilm formation was investigated. The interaction of niosomes with bacterial cells was also monitored using the scanning electron microscopy (SEM). Results: The efficacy of niosomes depended on their composition. Standard niosomes of Span 60 and cholesterol were similar to drug solution. Incorporation of Tween 80, oleic acid (OA), OA/propylene glycol or lecithin produced fluid niosomes which reduced the MIC and inhibited biofilm formation compared with drug solution. Incorporation of a positively charged agent into fluid niosomes enhanced the antibacterial activity and reduced biofilm formation significantly. SEM showed evidence of vesicle adsorption to the bacteria with possible adhesion or fusion with the cell membrane. The in vivo skin model confirmed the in vitro results with optimum niosomes being more efficient than drug solution. Conclusion: Niosomes are promising for enhanced antibacterial activity and reduced resistance to antibiotics. The later can be achieved by inhibition of biofilm formation.

Journal of Advanced Medical and Pharmaceutical Research, 2020

Since penicillin was discovered by Sir Alexander Fleming in 1928, antibiotics have been used in m... more Since penicillin was discovered by Sir Alexander Fleming in 1928, antibiotics have been used in medicine to treat different infections and combat pathogenic microorganisms. Nevertheless, with their increasing and massive use, the progress of resistance has become more predominant and many bacteria have developed resistance to multiple classes of antibacterial agents through genetic exchange mechanisms. Consequently, the use of antibiotics is now under threat. Antibiotic resistance poses a worldwide hazard to both human and animal health and it has become an important public health concern in the 21 st century. This review aims to survey some mechanisms of antibiotic resistance. Furthermore, some novel approaches like the use of nanoparticle-based antimicrobial drug delivery, fecal microbiota transfer, antimicrobial peptides, antibiotic adjuvants, antisense antimicrobials, phage therapy, antivirulence strategies, host oriented therapy, synthesis of new antimicrobials and extraction of antimicrobials from a natural source like plants are identified and discussed in an attempt to combat and fight against bacterial resistance.

MicroRNAs regulate the expression of many genes and subsequently control various cellular process... more MicroRNAs regulate the expression of many genes and subsequently control various cellular processes, such as the immune response to viral infections mediated by type I interferon (IFN). In this study, the expression pattern of two interferon-related microRNAs, miR-146a and miR-155, was examined in healthy and HCV-genotype-4-infected peripheral blood mononuclear cells (PBMCs) using qRT-PCR. In contrast to other viral infections, the expression pattern was similar in both healthy and infected PBMCs. This could be attributed to attenuation of IFN pathway by HCV, which was assessed by investigating the expression of MxA, an interferon-stimulated gene, that showed lower expression in HCV-infected PBMCs. To determine the site of interference of HCV in the IFN pathway, expression of both microRNAs was examined following stimulation of PBMCs with IFN-α2a, an activator of the JAK/STAT pathway as well as with imiquimod, a toll-like receptor-7 (TLR-7) agonist that promotes interferon release. IFN stimulation induced the expression of miR-146a and miR-155 in HCV-infected and healthy PBMCs. Stimulation with imiquimod led to a down-regulation of both microRNAs in infected PBMCs, while it increased their expression in healthy PBMCs, indicating that HCV might interfere with miR-146a and miR-155 expression at sites upstream of interferon release, specifically in the TLR-7 pathway. The pattern of expression of both miR-146a and miR-155 was very similar with a strong positive correlation, but showed no correlation to the patients' clinical or histopathological parameters or response to treatment. In conclusion, HCV infection might repress the induction of miR-146a and miR-155 by interfering with TLR-7 signaling.

Epidemiological relationships were investigated between 40 methicillin-resistant Staphylococcus a... more Epidemiological relationships were investigated between 40 methicillin-resistant Staphylococcus aureus (MRSA) strains with decreased glycopeptide susceptibility isolated from November 1998 to March 1999 from 39 patients (17 infected and 22 colonized patients) in nine wards of the Broussais Hospital, Paris, France. Reduced glycopeptide susceptibility was readily detected on brain heart infusion (BHI) agar containing 6 g of teicoplanin per ml and on gradient plates, but not by the standard disk diffusion method. The MICs of vancomycin and teicoplanin, determined on BHI agar, were 4 and 8 to 32 g/ml, respectively (standard antibiotic dilution), and 4 to 8 and 8 to 32 g/ml, respectively (E-test). All strains were resistant to macrolides, aminoglycosides, tetracycline, rifampin, sulfonamides, and pefloxacin, showed reduced susceptibility to fusidic acid and fosfomycin, and were susceptible to trimethoprim and chloramphenicol. Pulsed-field gel electrophoresis and lysotyping revealed that a multidrug-resistant MRSA clone with decreased susceptibility to glycopeptides has been discretely endemic since at least 1996 in our institution, where it was responsible for an outbreak in November and December 1998.

African journal of microbiology research

Background and objectives: Plasmids have been known to play a major role

Pakistan Journal of Biological Sciences

African journal of microbiology research

Published data concerning correlation between virulence factors and resistance markers is relativ... more Published data concerning correlation between virulence factors and resistance markers is relatively scarce. The aim of this study was to determine the relationship between antibiotic resistance, gelatinase production and pheromone response in the Enterococcus faecalis pathogens isolated from Egypt. Out of the 19 E. faecalis clinical isolates, 5 were able to produce gelatinase enzyme. These virulent isolates were multidrug resistant and showed high level vancomycin resistance. They were tested for mating ability. They cotransfered pheromone response genes together with vancomycin resistance determinants and gelatinase production to sensitive recipient strains. The gel E gene was detected in all donor isolates and their corresponding transconjugants phenotypically and genotypically. The PCR amplicons of a heavy gelatinase producing isolate and its transconjugants were subjected to sequencing. Significant homology was detected with OG1RF strain following sequence search with a GenBank...

Journal of Pharmacy and Pharmacology, 1990

Brazilian Journal of Microbiology, 2012

African journal of microbiology research

Published data concerning correlation between virulence factors and resistance markers is relativ... more Published data concerning correlation between virulence factors and resistance markers is relatively scarce. The aim of this study was to determine the relationship between antibiotic resistance, gelatinase production and pheromone response in the Enterococcus faecalis pathogens isolated from Egypt. Out of the 19 E. faecalis clinical isolates, 5 were able to produce gelatinase enzyme. These virulent isolates were multidrug resistant and showed high level vancomycin resistance. They were tested for mating ability. They cotransfered pheromone response genes together with vancomycin resistance determinants and gelatinase production to sensitive recipient strains. The gel E gene was detected in all donor isolates and their corresponding transconjugants phenotypically and genotypically. The PCR amplicons of a heavy gelatinase producing isolate and its transconjugants were subjected to sequencing. Significant homology was detected with OG1RF strain following sequence search with a GenBank...

Zentralblatt für Bakteriologie, Mikrobiologie und Hygiene. Serie B, Umwelthygiene, Krankenhaushygiene, Arbeitshygiene, präventive Medizin, 1989

Fifty items of Al-Kohl collected from northern Jordanian provinces representing: 20 unopened read... more Fifty items of Al-Kohl collected from northern Jordanian provinces representing: 20 unopened ready to use samples purchased from retail outlets, 20 in-use samples obtained from ladies of different socioeconomic standards and 10 samples of the original stones (used for Al-Kohl preparation) were examined for their microbial contents. Ready to use and in-use samples were much more contaminated than the original stones. On sterility testing, more than 85% of the unused and in-use samples were contaminated with bacteria and or fungi comparing to 50% of the original stone samples. Quantitatively, 90% of the original stones contained less than 100 bacterial or fungal cells/g and the other remaining 10% were in the range of 10(2)-10(3) cfu/g either for bacterial or fungal counts. The level and distribution of the viable microbial counts in unused and in-use samples were comparable and much higher than original stones. More than 70% and 20% of those items contained more than 100 cfu/g of bac...

Immunological Investigations, 2015

A group of 11 medicinal plants, including Lavandula pubescens, Trigonella foenugricium, Salsola s... more A group of 11 medicinal plants, including Lavandula pubescens, Trigonella foenugricium, Salsola schweinforthi, Calligonum comosum, Silene succulenta, Silene villosa, Bogonvillea glabra, Cakile maritime, Gomphrene celesoids, Mirabilis jalaba, and Silene nocturna growing in Egypt, were extracted and examined for their immunomodulatory and antioxidant activities. RAW 264.7 cells were recruited to investigate the immunomodulatory effect through multiple parameters analysis. First, the proliferation index of macrophages cells was evaluated revealing that Trigonella foenugricium, Silene succulenta and Silene villosa have a significant cytotoxic effect on RAW cells. Interestingly, we observed enhancement of macrophages phagocytic function of by all extracts except Cakile maritime, Gomphrena celosioides and Silene nocturna. Afterwards, macrophages were challenged by incubation with LPS and the effect of various extracts on inflammatory responses was investigated; the generation of NO from activated macrophage was substantially suppressed by 7 extracts namely, Trigonella foenugricium, Calligonum comosum, Silene succulenta, Bougainvillea glabra, Mirabilis jalaba, Gomphrena celosioides and Silene nocturna. TNF-a was decreased by percentage range from 3.8 to 85.8% and Trigonella foenugricium extract showed the highest inhibition of TNF-a release. All extracts except Trigonella foenugricium, Salsola schweinforthi, Silene succulenta and Mirabilis jalaba significantly inhibited COX-2 production from stimulated macrophage. Moreover, evaluating the potential antioxidant activity of these extracts showed that Trigonella foenugricium, Salsola schweinforthi, Calligonum comosum, Bogonvillea glabra and Mirabilis jalaba exhibited some antioxidant activities. Taken together, our results suggest that some of these extracts may have a considerable antinflammatory and antioxidant effects and may be a potential therapeutic choice in the treatment of inflammatory diseases.

Pharmaceutical Biology, 1990

... Cytotoxicity, Mutagenicity and Antimicrobial Activity of Forty Jordanian Medicinal Plants Ahm... more ... Cytotoxicity, Mutagenicity and Antimicrobial Activity of Forty Jordanian Medicinal Plants Ahmad S. ALKDFAHI*, Ahmad ABDELAZIZ*, Ibrahim MAHMOUD*, Mustafa ABUIRJIE*, Abdelrahim HUNAITI** AND Ahmad EL-OQLA** ABSTRACT ...

Immunopharmacology and Immunotoxicology, 2011

A group of medicinal plant including Silene (Silene nocturna), Black seed (Nigella sativa) and Ch... more A group of medicinal plant including Silene (Silene nocturna), Black seed (Nigella sativa) and Chamomile (Matricaria chamomilla) growing in Egypt were examined for their immunomodulatory effect in Balb/c mice. Treatment (intraperitoneal injection) with five doses of methanolic extract for each plant was found to enhance the total white blood cells count (up to 1.2 × 10(4) cells/mm(3)). Bone marrow cellularity also increased significantly (P < 0.01) after the administration of the extract of each of three test plants. Furthermore, spleen weight of the treated groups was significantly increased (P < 0.01). Two groups of mice were immunosuppressed with cyclophosphamide, the one which pretreated with the plants extracts significantly (P < 0.01) restored their resistance against lethal infection with the predominately granulocyte-dependant Candida albicans. These results confirm the immunomodulatory activity of Silene, Black seed, and Chamomile extracts and may have therapeutical implications in prophylactic treatment of opportunistic infections and as supportive treatment in oncogenic cases.

Objective: The aim was to optimize norfloxacin niosomes for enhanced antibacterial activity and r... more Objective: The aim was to optimize norfloxacin niosomes for enhanced antibacterial activity and reduced bacterial resistance. Methods: Pseudomonas aeruginosa, a biofilm forming bacterium, was used as the test organism. Different norfloxacin niosomes were evaluated in vitro and in vivo, respectively, for antibacterial activity compared with aqueous drug solution. The influence of norfloxacin niosomes on biofilm formation was investigated. The interaction of niosomes with bacterial cells was also monitored using the scanning electron microscopy (SEM). Results: The efficacy of niosomes depended on their composition. Standard niosomes of Span 60 and cholesterol were similar to drug solution. Incorporation of Tween 80, oleic acid (OA), OA/propylene glycol or lecithin produced fluid niosomes which reduced the MIC and inhibited biofilm formation compared with drug solution. Incorporation of a positively charged agent into fluid niosomes enhanced the antibacterial activity and reduced biofilm formation significantly. SEM showed evidence of vesicle adsorption to the bacteria with possible adhesion or fusion with the cell membrane. The in vivo skin model confirmed the in vitro results with optimum niosomes being more efficient than drug solution. Conclusion: Niosomes are promising for enhanced antibacterial activity and reduced resistance to antibiotics. The later can be achieved by inhibition of biofilm formation.