Microbiological study of certain genes associated with biofilm forming capacity of Methicillin resistant Staphylococcus aureus in Egypt: An eye on Nifedipine repurposing

Abstract

Background: Staphylococcus aureus remains one of the most prevalent pathogens associated with several infections. We aim to evaluate the biofilm forming capacity along with the presence of biofilm-associated genes in MRSA from surgical wound infections. In addition, potential antimicrobial activity of nifedipine was investigated.  Methods: A total of 50 MRSA isolates were collected form surgical wound samples from clinical laboratories. The antimicrobial susceptibility and biofilm forming capacity were screened. PCR was used to detect icaA, icaD, hla, sirB, ebpS, fnbA, clfA, sdr and can genes. The antimicrobial and antibiofilm effect of nifedipine, alone and combined with levofloxacin, was determined. Preliminary molecular docking was employed to predict the binding affinity between nifedipine and different target proteins. Spa typing was performed to analyze MRSA strains. Results: All MRSA strains were multidrug-resistant and biofilm producers. The most abundant gene was hla (96%), followed by icaA and sirB with equal prevalence (88%). Biofilm formation was significantly associated with icaA, icaD, sdrE and sirB genes. In addition to the antibiofilm activity of nifedipine, there was a synergistic effect between it and levofloxacin, this finding was further given strength to by molecular docking where nifedipine had a binding affinity to HTH-type transcriptional regulator qacR. For the first time in Egypt, spa type t314 was reported. Conclusion: Nifedipine, alone and combined with levoflocaxin, showed promising results as antimicrobial and antibiofilm agent. Such effect might be due to efflux inhibition activity and worth additional investigation to understand the underlying mechanism.