Rehab Mahmoud Abd El-Baky

Design, synthesis, molecular docking, anti-Proteus mirabilis and urease inhibition of new fluoroquinolone carboxylic acid derivatives

New hydroxamic acid, hydrazide and amide derivatives of ciprofloxacin in addition to their analogues of levofloxacin were prepared and identified by different spectroscopic techniques. Some of the prepared compounds revealed good activity against the urease splitting bacteria, Proteus mirabilis. The urease inhibitory activity was investigated using indophenol method. Most of the tested compounds showed better activity than the reference acetohydroxamic acid (AHA). The ciprofloxacin hydrazide derivative 3a and levofloxacin hydroxamic acid 7 experienced the highest activity (IC50=1.22μM and 2.20μM, respectively). Molecular docking study revealed high spontaneous binding ability of the tested compounds to the active site of urease.

Prevalence of Extended-Spectrum Beta-Lactamase, AmpC Beta- Lactamase, and Metallo-Beta-Lactamase among Clinical Isolates of Pseudomonas aeruginosa

Objectives : to study prevalence of ESBLs, AmpC beta‑lactamase and metallo‑beta‑lactamase among clinical isolates of P. aeruginosa . Materials and Methods : P. aeruginosa were isolated and identified by the traditional microbiological procedure, ESBLs were detected by combined disk diffusion method according CLSI recommendations, AmpC beta-lactamase was detected by iodometric methods, MBL was detected by disc potentiation test and Agar dilution method for antibiotic susceptibility testing. Results : Out of 330 samples of different types of infections, 58 were positive for P. aeruginosa . All isolates showed high resistance to most of the tested antimicrobials but showed low resistance to amikacin. Forty-two (72.4%) isolates were detected as β-lactamase producers, 16 (27.5%) isolates were positive for ESBLs while 31(53.4%) were MBL producing strains. All ESBL and MBL producers were highly resistant to the tested antimicrobials. Plasmid profile showed that 9 isolates were plasmid mediated. Conclusion : The study emphasizes a high prevalence of multidrug-resistant P. aeruginosa producing beta‑lactamase enzymes of diverse mechanisms especially in burn units. Proper antibiotic policy and measures should be taken to minimize the emergence of this multiple β‑lactamase producing pathogens and also the danger of their dissemination to other bacteria by plasmids which may carry resistance genes for other antimicrobials.

Bacterial Growth Inhibitory Effect of Ceratonia siliqua L. Plant Extracts Alone and in Combination with Some Antimicrobial Agents

Objectives: To evaluate the antibacterial activity of the total extracts, methanolic and water extract of leaves with stems and the pods of Ceratonia siliqua L. each alone and in combination with some antimicrobials on some pathogens. As the wide use of antibiotics in the treatment of bacterial infections has led to the emergence and spread of resistant strains. Many studies showed that the efficacy of antimicrobials can be improved by combining them with crude plant extracts. Materials and Methods: the antibacterial activity of the total extracts, methanolic and water extract of leaves with stems and the pods of Ceratonia siliqua L. each alone and in combination with some antimicrobials was evaluated using well- diffusion method. Cytotoxicity of the total methanolic extract against Huh-7 liver and A-495 lung cancer cell lines was assessed using SRB method. Results: Well diffusion method demonstrates an in-vitro antibacterial activity of the tested extracts against tested microorganisms. Combination of the tested extracts with antimicrobials increased the activity of the tested antimicrobials. A dose dependant effect on both Huh-7 liver and A-495 lung cancer cells was observed. Conclusion: Our results revealed the importance of plant extracts when associated with antibiotics to control resistant bacteria that become a threat to human health. In addition, the tested plant extracts can be exposed for further investigation to be used as hepatoprotective agent.

Isolation and evaluation of cocktail phages for the control of multidrug-resistant Escherichia coli serotype O104: H4 and E. coli O157: H7 isolates causing diarrhea

Abstract Escherichia coli serotype O157: H7 and E. coli O104: H4 are well known foodborne pathogens causing sever enteric illness. Using bacteriophages as biocontrol agents of some foodborne pathogens and multidrug‐resistant (MDR) bacteria has a great attention nowadays. This study aims to test the effect of cocktail phages on the growth of some foodborne pathogens and MDR E. coli. Routine conventional PCR was used to confirm the identification of E. coli isolates. Double‐layered culture technique was used to isolate phages from sewage water. Morphology of bacteriophage was described using transmission electron microscopy, and spot test was performed to determine host range of the phage cocktail. Phage cocktail of Siphoviridae and Podoviridae family infecting E. coli O157: H7, E. coli O104: H4 and untypeable E. coli (neither O157 nor O104) has been isolated from sewage water. Phage cocktail showed both lytic and lysogenic activity. Lytic activity was observed against E. coli O157: H7, E. coli O104: H4 isolates, Staphylococcus. aureus ATCC6538 and Pseudomonas aeruginosa ATCC 10145, while the lysogenic activity was observed against the untypeable strain. The tested phage cocktail showed a promising inhibitory action on E. coli O157: H7 and O104: H4, S. aureus ATCC6538 and P. aeruginosa ATCC 10145, suggesting the possibility of its use as a biocontrol tool or as natural food preservatives for many food products. Figure. No Caption available.

Comparative Antimicrobial Activity and Durability of Different Glass Ionomer Restorative Materials with and without Chlorohexidine

Objectives : To evaluate the in vitro antibacterial effect of three different restorative materials (Glass Ionomer Cements (GIC)) containing chlorohexidine on Streptococcus mutans , and lactobacillus acidophilus. Materials and Methods : Three commercially available glass ionomer cements, i.e., Fuji 1X (GIC1), Ketac molar (GIC2) and Riva (GIC3) were evaluated each alone and in combination with chlorohexidine diacetate or chlorohexidine digluconate. GICs were manipulated in accordance with manufacturer’s guidelines and embedded in wells made-up in plates of trypticase soy agar seeded with Streptococcus mutans and Lactobacillus MRS agar seeded with Lactobacillus acidophilus . The antibacterial activity was evaluated by using a caliper to measure the diameter of growth inhibition zones. The study was performed in triplicate and Duncan post-Hoc Multiple comparisons at p≤ 0.05 is used for means comparison. Results : the three Glass ionomers with chlorohexidine diacetate powder (1%) showed the highest activity and prolonged effect on the tested strains compared to glass ionomers free from chlorohexidine and the other glass ionomers with chlorohexidine digluconate liquid. Also, it was found that Fuji IX glass ionomer showed higher and prolonged effect in comparison to Ketac-Molar and Riva glass ionomers. Glass ionomers in combination with chlorohexidine diacetate showed higher efficacy against streptococcus mutans than for lactobacillus acidophilus. Conclusion : All three GIC’s under evaluation, promoted growth inhibition of the cariogenic bacteria assayed. Fuji IX glass ionomer with chlorohexidine diacetate showed the highest efficacy and durability against the tested strains.

In vitro Efficacy of Ureteral Catheters Impregnated with Ciprofloxacin, N-acetylcysteine and their Combinations on Microbial Adherence

Background Ureteral catheters are valuable indispensable devices may readily acquire biofilms on the inner or outer surfaces. This study evaluated the efficacies of ureteral catheters impregnated with ciprofloxacin, N-acetylcysteine each alone and in combination on microbial adherence. Methods Antimicrobial durability of ureteral catheters coated, through instant dip method, with ciprofloxacin were determined using modified Kirby-Bauer method. Ciprofloxacin-coated catheters showed zones of inhibition ranged from 15 to 45 mm in diameter (baseline) against nine clinical strains recently isolated from patients undergoing ureteral stent removal. Segments coated with ciprofloxacin, N-acetylcysteine each alone and in combination, through instant dip method, were incubated with the tested microorganisms, washed, sonicated, cultured and the number of viable cells were determined. Results Ciprofloxacin-coated catheters soaked in urine and incubated at 37 °C, maintained antimicrobial activities and produce zones of inhibition that measured 2–10 mm for at least 8 weeks. Effect of ciprofloxacin and N-acetylcysteine coated catheters on microbial adherence were found to be dose dependent. Catheters impregnated with ciprofloxacin/N-acetylcysteine showed the highest inhibitory effect on microbial adherence when compared with controls (85.5%–100%). Conclusion Catheters impregnated with ciprofloxacin, using instant dip method, were shown to have broad spectrum, prolonged antimicrobial durability and high efficacy. On the other hand, Catheters impregnated with ciprofloxacin/NAC showed the highest inhibitory effect on microbial adherence to stent surfaces.