ABSTRACT
Staphylococcus aureus (S. aureus) is a commensal bacterium and an opportunistic pathogen causing a wide variety of infections ranging from localized skin and soft tissue infections to life-threatening severe bacteremia, osteomyelitis, endocarditis, atopic dermatitis, prosthetic joint infection, staphylococcal food poisoning, medical device-related infections, and pneumonia. It is attributed to an acquired resistant gene, mecA, encoding penicillin-binding protein 2a (PBP2a). PBP2a is an essential protein responsible for the resistivity of methicillin-resistant S. aureus (MRSA) to various beta-lactam antibiotics. The antimicrobial treatment alternatives for MRSA are increasingly limited. Therefore, developing alternative therapeutic options for its treatment is the need of the day. Phthalimides and their N-substituted derivatives are of biological importance as they possess extensive biological and pharmaceutical properties and can serve as an excellent therapeutic option for MRSA. This study uses three chiral phthalimides (FIA, FIB, and FIC) to check their in silico and in vitro inhibitory effects. Molecular docking of these chiral phthalimides against PBP2a of MRSA was performed initially. After promising results, these novel compounds were screened through the agar-well diffusion method and micro-broth dilution assay to investigate their in vitro inhibitory activities with FIB being the strongest anti-staphylococcal agent yielding a 21 mm zone of inhibition and a minimum inhibitory concentration (MIC) of 0.022 ug, respectively. The zones of inhibition obtained through the in vitro activity showed that these chiral phthalimides possess substantial anti-MRSA activities and have the potential to be considered as alternative chemotherapeutics to treat the infections caused by MRSA after the confirmation of their cytotoxic and pharmacokinetic studies.
ABSTRACT
Background: Many anogenital cancers are caused by high-risk HPV. The most common subtype is HPV16, which is prevalent in the world, including Pakistan. Various amino acid residues in HPV16 E5 are associated with high cell cycle progression and proliferation. Lack of studies on HPV16E5 in Pakistan prompted the current study. This is the first report on the occurrence of pathogenic E5 variant of HPV16 in tissue sections obtained from invasive cervical cancerous patients in Pakistan. Methods: A subset of 11 samples from HPV-positive biopsies were subjected to E5 gene amplification using PCR and analyzed using bioinformatics programs. The bioinformatics analysis detected mutations causing structural variations, which potentially contribute to the oncogenic properties of proteins. Results: The two-point mutations, C3979A and G4042A, observed in isolate 11 caused the substitution of isoleucine for leucine and valine at positions 44 and 65 in E5 protein. The rest of the isolates had Leu44Val65 amino acids. Intratypic variations and phylogenetic analysis revealed that the majority of the isolates were closely clustered with European-Asian lineage. Moreover, C3979A and G4042A contributed to higher degree of interactions with host receptors, i.e. EGFR. Conclusion: This is the first study reporting HPV16 variants in a Pakistani population based on variations in the E5 region. Our findings indicate that isolate 11 has a strong interaction with the intracellular domain of EGFR, which may enhance the generation of downstream signals. Since this was a pilot study to explore E5 gene mutation, future studies with large samples are absolutely needed.
