Browsing by Author "Zaki, Bishoy M"

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    Bacteriophage as a potential therapy to control antibiotic-resistant Pseudomonas aeruginosa infection through topical application onto a full-thickness wound in a rat model
    (Academy of Scientific Research and Technology, 2022-09) Rezk, Nouran; Abdelsattar, Abdallah S; Elzoghby, Doaa; Agwa, Mona M; Abdelmoteleb, Mohamed; Aly, Rania G; Fayez, Mohamed S; Essam, Kareem; Zaki, Bishoy M; El‑Shibiny, Ayman
    Background: Antibiotic-resistant Pseudomonas aeruginosa (P. aeruginosa) is one of the most critical pathogens in wound infections, causing high mortality and morbidity in severe cases. However, bacteriophage therapy is a poten‑ tial alternative to antibiotics against P. aeruginosa. Therefore, this study aimed to isolate a novel phage targeting P. aeruginosa and examine its efcacy in vitro and in vivo. Results: The morphometric and genomic analyses revealed that ZCPA1 belongs to the Siphoviridae family and could infect 58% of the tested antibiotic-resistant P. aeruginosa clinical isolates. The phage ZCPA1 exhibited thermal stability at 37 °C, and then, it decreased gradually at 50 °C and 60 °C. At the same time, it dropped signifcantly at 70 °C, and the phage was undetectable at 80 °C. Moreover, the phage ZCPA1 exhibited no signifcant titer reduction at a wide range of pH values (4–10) with maximum activity at pH 7. In addition, it was stable for 45 min under UV light with one log reduction after 1 h. Also, it displayed signifcant lytic activity and bioflm elimination against P. aeruginosa by inhibiting bacterial growth in vitro in a dose-dependent pattern with a complete reduction of the bacterial growth at a multiplicity of infection (MOI) of 100. In addition, P. aeruginosa-infected wounds treated with phages displayed 100% wound closure with a high quality of regenerated skin compared to the untreated and gentamicin-treated groups due to the complete elimination of bacterial infection. Conclusion: The phage ZCPA1 exhibited high lytic activity against MDR P. aeruginosa planktonic and bioflms. In addition, phage ZCPA1 showed complete wound healing in the rat model. Hence, this research demonstrates the potential of phage therapy as a promising alternative in treating MDR P. aeruginosa.
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    Occurrence and Molecular Study of Hypermucoviscous/Hypervirulence Trait in Gut Commensal K. pneumoniae from Healthy Subjects
    (MDPI AG, 2023-04) Osama, Dina M; Zaki, Bishoy M; Khalaf, Wafaa S; Mohamed, Marwa Yousry A; Tawfick, Mahmoud M; Amin, Heba M
    Hypervirulent Klebsiella pneumoniae (hvKp) is emerging worldwide. Hypermucoviscousity is the characteristic trait that distinguishes it from classic K. pneumoniae (cKp), which enables Kp to cause severe invasive infections. This research aimed to investigate the hypermucoviscous Kp (hmvKp) phenotype among gut commensal Kp isolated from healthy individuals and attempted to characterize the genes encoding virulence factors that may regulate the hypermucoviscosity trait. Using the string test, 50 identified Kp isolates from healthy individuals’ stool samples were examined for hypermucoviscosity and investigated by transmission electron microscopy (TEM). Antimicrobial susceptibility profiles of Kp isolates were determined using the Kirby Bauer disc method. Kp isolates were tested for genes encoding different virulence factors by PCR. Biofilm formation was assayed by the microtiter plate method. All Kp isolates were multidrug-resistant (MDR). Phenotypically, 42% of isolates were hmvKp. PCR-based genotypic testing revealed the hmvKp isolates belonged to capsular serotype K2. All study Kp isolates harbored more than one virulence gene. The genes magA and rmpA were not detected, while the terW gene was present in all isolates. The siderophores encoding genes entB and irp2 were most prevalent in hmvKp isolates (90.5%) and non-hmvKp (96.6%), respectively. hmvKp isolates harbored the genes wabG and uge with rates of 90.5% and 85.7%, respectively. The outcomes of this research highlight the potential health risk of commensal Kp to cause severe invasive diseases, owing to being hmvKp and MDR, and harboring multiple virulence genes. The absence of essential genes related to hypermucoviscosity such as magA and rmpA in hmvKp phenotypes suggests the multifactorial complexity of the hypermucoviscosity or hypervirulence traits. Thus, further studies are warranted to verify the hypermucoviscosity-related virulence factors among pathogenic and commensal Kp in different colonization niches.