Effects of selected methanolic and ethereal medicinal plant extracts on efflux pumps of klebsiella pneumoniae and escherichia coli strains isolated from patients at mulago national referral hospital

Abstract

Background: Antimicrobial resistance (AMR) is a significant global health issue, with multidrug-resistant (MDR) Enterobacterales increasingly prevalent in Ugandan healthcare. Efflux pumps contribute to AMR, enabling resistance to antibiotics like Tetracycline. Data exists on tetraccyline’s performance against MDR Enterobacterales in Uganda. Medicinal plant extracts show promise as alternative/adjunctive therapies due to their potent biological activity. This study investigated selected plant extracts' role in reversing efflux pump-mediated resistance in MDR Escherichia coli and Klebsiella pneumonia in Uganda, using tetracycline as the test antibiotic.

Objective: To assess the effect of selected methanolic and ethereal medicinal plant extracts on efflux pump activity among MDR Escherichia coli and Klebsiella pneumoniae isolates at Mulago National Referral Hospital, Kampala, Uganda.

Materials and Methods: The study analyzed clinical isolates of E. coli and K. pneumonia from patients in an urban hospital. A total of 70 clinical isolates resistant to atleast three antibiotic classes including Tetracycline were selected from a pool of 385 strains at the Department of Medical Microbiology, Makerere University. Efflux pump activity of the strains was assessed by determining the effect of Omeprazole, a known proton pump inhibitor, on the MICS of tetracycline using the agar dilution method. Medicinal plant extracts underwent standard extraction procedures and antimicrobial testing via the agar well diffusion method. MIC values were assessed in the presence and absence of sub-inhibitory antibiotic concentrations to evaluate the extracts’ potentiation effects on Tetracycline.

Results: Omeprazole significantly reduced tetracycline MICs to a value less than 2mcg./mL(p< 0.001) in 70 MDR E. coli and K. pneumonia isolates, confirming robust efflux pump inhibition. For plant extracts’inherent activity, Mango ether extract had highest MIC of 31.25 mcg/mL, followed by garlic and eucalyptus extracts that had moderate activity.Tetracycline potentiation with plant extracts was untested due to insufficient volumes. It is recommended to exploreOmeprazole’s mechanism, securie resources for mango, garlic, and ginger potentiation with tetracycline, and extending MIC tests to more antibiotics for enhanced MDR management