In Vitro and In Vivo Effect of Amikacin and Imipenem Combinations against Multidrug-Resistant E. coli

Sara Mahmoud Farhan; Rehab Mahmoud Abd El-Baky; Salah Abdalla; Ahmed Osama El-Gendy; Hala Rady Ahmed; Doaa Safwat Mohamed; Amr El Zawily; Ahmed Farag Azmy

doi:10.3390/tropicalmed7100281

In Vitro and In Vivo Effect of Amikacin and Imipenem Combinations against Multidrug-Resistant E. coli

Trop Med Infect Dis. 2022 Oct 2;7(10):281. doi: 10.3390/tropicalmed7100281.

Authors

Sara Mahmoud Farhan^{1

2}, Rehab Mahmoud Abd El-Baky^{2

3}, Salah Abdalla⁴, Ahmed Osama El-Gendy¹, Hala Rady Ahmed³, Doaa Safwat Mohamed⁵, Amr El Zawily^{6

7}, Ahmed Farag Azmy¹

Affiliations

¹ Department of Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef 62514, Egypt 2 Department of Microbiology and Immunology, Faculty of Pharmacy, Deraya University, Minia 11566, Egypt 3 Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia 61519, Egypt 4 Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt 5 Department of Microbiology and Immunology, Faculty of Pharmacy, Sohag University, Sohag 82524, Egypt 6 Department of Plant and Microbiology, Faculty of Science, Damanhour University, Damanhour 22511, Egypt 7 Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, IA 52242, USA.
² Department of Microbiology and Immunology, Faculty of Pharmacy, Deraya University, Minia 11566, Egypt.
³ Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia 61519, Egypt.
⁴ Department of Microbiology and Immunology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt.
⁵ Department of Microbiology and Immunology, Faculty of Pharmacy, Sohag University, Sohag 82524, Egypt.
⁶ Department of Plant and Microbiology, Faculty of Science, Damanhour University, Damanhour 22511, Egypt.
⁷ Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, Iowa City, IA 52242, USA.

Abstract

The emergence of multidrug-resistant (MDR) E. coli has developed worldwide; therefore, the use of antibiotic combinations may be an effective strategy to target resistant bacteria and fight life-threatening infections. The current study was performed to evaluate the in vitro and in vivo efficacy of amikacin and imipenem alone and in combination against multidrug-resistant E. coli. Methods: The combination treatment was assessed in vitro using a checkerboard technique and time-killing curve and in vivo using a peritonitis mouse model. In resistant isolates, conventional PCR and quantitative real-time PCR techniques were used to detect the resistant genes of Metallo-β-lactamase gene Imipenemase (bla-_IMP) and aminoglycoside 6'-N-acetyltransferase (aac (6')-Ib). Scanning electron microscopy was used to detect the morphological changes in the resistant isolates after treatment with each drug alone and in combination. In vitro and in vivo studies showed a synergistic effect using the tested antibiotic combinations, showing fractional inhibitory concentration indices (FICIs) of ≤0.5. Regarding the in vivo study, combination therapy indicated a bactericidal effect after 24 h. E. coli isolates harboring the resistant genes Metallo-β-lactamase gene Imipenemase (bla-_IMP) and aminoglycoside 6'-N-acetyltransferase (aac (6')-Ib) represented 80% and 66.7%, respectively, which were mainly isolated from wound infections. The lowest effect on Metallo-β-lactamase gene Imipenemase (bla-_IMP) and aminoglycoside 6'-N-acetyltransferase (aac (6')-Ib) gene expression was shown in the presence of 0.25 × MIC of imipenem and 0.5 × MIC of amikacin. The scanning electron microscopy showed cell shrinkage and disruption in the outer membrane of E. coli in the presence of the antibiotic combination. Amikacin and imipenem combination can be expected to be effective in the treatment and control of serious infections caused by multidrug-resistant (MDR) E. coli and the reduction in bacterial resistance emergence.

Keywords: E. coli; Metallo-β-lactamase gene Imipenemase (bla-IMP); SEM; amikacin; aminoglycoside 6′-N-acetyltransferase (aac (6′)-Ib) genes; drug combination; imipenem; synergism.

Grants and funding

This research received no external funding.