In vitro effects of quinine on the antibacterial activity of erythromycin against bacteria of clinical relevance
Department of Microbiology, School of Science and Technology, PMB 4005, Babcock University, Ilisan-Remo, Ogun State, Nigeria.
Research Article
GSC Biological and Pharmaceutical Sciences, 2021, 14(02), 077-086.
Article DOI: 10.30574/gscbps.2021.14.2.0033
Publication history:
Received on 12 January 2021; revised on 08 February 2021; accepted on 10 February 2021
Abstract:
The study investigated the in vitro effects of quinine on the antibacterial activity of erythromycin for possible interactions. The antibacterial activities of each drug and their combinations were investigated by agar diffusion, agar and macrobroth dilution methods. While 100 µl of 1000 µg/ml of erythromycin produced inhibition zones ranging between 13 and 31 ± 1.0 mm in all the isolates except K. pneumoniae and P. aeruginosa ATCC 19582, combining the highest concentration of erythromycin with 35 µg/ml of quinine produced inhibition zones ranging between 14 and 34 ± 1.0 mm with the exception of S. flexneri KZN. Though quinine had no antibacterial effects on the isolates, erythromycin was effective at minimum inhibitory concentrations (MICs) ranging between 25 and 100 µg/ml while their combinations resulted in reduction of MICs of most of the isolates to 12.5 µg/ml except those against A. calcaoceuticus anitratus CSIR, Ps. aeruginosa ATCC 15442, P. shigelloides ATCC 51903, A. hydrophila ATCC 35654, Ps. aeruginosa ATCC 19582 and E. faecalis KZN that remained unchanged in agar dilution. While the MICs of erythromycin ranged between 25 and 50 µg/ml, the MICs of this antibiotic was reduced to concentrations ranging between 12.5 and 50 µg/ml indicating 50% to 75% in the presence of quinine. The combination of erythromycin and quinine, in vitro, resulted in synergistic (50%), additive/indifference (44.44%) and antagonistic (11.11%) interactions while quinine at concentrations lower than plasma quinine concentrations was inhibitory to the antibacterial activity of erythromycin. The synergistic effect may serve as remedy for bacterial infections in which the test bacteria have been implicated.
Keywords:
Antibacterial combination; Erythromycin; Resistance; Synergism; Quinine
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Copyright © 2021 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0
