Plasmid‐Mediated AmpC Detection in Escherichia coli and Klebsiella pneumoniae : In Vitro Prevalence and In Silico Inhibitor Design
Muhammad Sarfraz, Aatif Amin, Muhammad Naveed, Mehboob Ahmed, Shahida Hasnain, Saima Naz, Mohsin Khurshid, Mohsin Tassawar Cheema, Samman Ikram, Ajaz AhmadObjectives
This study investigated the prevalence of AmpC beta‐lactamase‐producing Escherichia coli and Klebsiella pneumoniae in clinical specimens collected in Lahore, Pakistan, and aimed to identify potential inhibitors targeting AmpC beta‐lactamases.
Methods
A total of 17,500 clinical specimens were collected from June 2018 to June 2021 and analyzed for E. coli and K. pneumoniae . These isolates underwent phenotypic identification using microscopy and the API 20E kit. AmpC beta‐lactamase production was initially screened using cefoxitin disk diffusion and inhibitor‐based methods, while the presence of plasmid‐borne AmpC genes (CIT, EBC, and DHA) was confirmed by PCR. Additionally, the study used computational drug discovery techniques to screen for oxadiazole, quinazolinone, and sulfonylurea derivatives as potential inhibitors of the AmpC protein.
Results
Our data showed high antibiotic resistance rates among E. coli and K. pneumoniae isolates: 74.5% were resistant to cefotaxime and ceftazidime, and 45% to cefoxitin. PCR testing revealed that the CIT gene was the most prevalent in both E. coli (65.4%) and K. pneumoniae (63%), while other genes (EBC and DHA) and combinations were also present ( p < 0.005). Using computational drug discovery, several compound libraries were screened against the AmpC protein. Tolbutamide showed the most promising results, with strong binding affinity and favorable drug‐like properties.
Conclusion
Plasmid‐mediated AmpC beta‐lactamase‐producing E. coli and K. pneumoniae were highly prevalent, with the CIT genotype predominating among clinical isolates. Computational screening identified Tolbutamide as a promising lead compound, warranting further experimental validation before therapeutic application.