In vitro Antimicrobial Activity of Robenidine, Ethylenediaminetetraacetic Acid and Polymyxin B Nonapeptide Against Important Human and Veterinary Pathogens

The emergence and global spread of antimicrobial resistance among bacterial pathogens demand alternative strategies to treat life-threatening infections. Combination drugs and repurposing of old compounds with known safety profiles that are not currently used in human medicine can address the proble...

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Main Authors: Manouchehr Khazandi, Hongfei Pi, Wei Yee Chan, Abiodun David Ogunniyi, Jowenna Xiao Feng Sim, Henrietta Venter, Sanjay Garg, Stephen W. Page, Peter B. Hill, Adam McCluskey, Darren J. Trott
Format: Article
Language:English
Published: Frontiers Media S.A. 2019-04-01
Series:Frontiers in Microbiology
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Online Access:https://www.frontiersin.org/article/10.3389/fmicb.2019.00837/full
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author Manouchehr Khazandi
Hongfei Pi
Wei Yee Chan
Abiodun David Ogunniyi
Jowenna Xiao Feng Sim
Henrietta Venter
Sanjay Garg
Stephen W. Page
Peter B. Hill
Adam McCluskey
Darren J. Trott
author_facet Manouchehr Khazandi
Hongfei Pi
Wei Yee Chan
Abiodun David Ogunniyi
Jowenna Xiao Feng Sim
Henrietta Venter
Sanjay Garg
Stephen W. Page
Peter B. Hill
Adam McCluskey
Darren J. Trott
author_sort Manouchehr Khazandi
collection DOAJ
description The emergence and global spread of antimicrobial resistance among bacterial pathogens demand alternative strategies to treat life-threatening infections. Combination drugs and repurposing of old compounds with known safety profiles that are not currently used in human medicine can address the problem of multidrug-resistant infections and promote antimicrobial stewardship in veterinary medicine. In this study, the antimicrobial activity of robenidine alone or in combination with ethylenediaminetetraacetic acid (EDTA) or polymyxin B nonapeptide (PMBN) against Gram-negative bacterial pathogens, including those associated with canine otitis externa and human skin and soft tissue infection, was evaluated in vitro using microdilution susceptibility testing and the checkerboard method. Fractional inhibitory concentration indices (FICIs) and dose reduction indices (DRI) of the combinations against tested isolates were determined. Robenidine alone was bactericidal against Acinetobacter baumannii [minimum inhibitory concentrations (MIC) mode = 8 μg/ml] and Acinetobacter calcoaceticus (MIC mode = 2 μg/ml). Against Acinetobacter spp., an additivity/indifference of the combination of robenidine/EDTA (0.53 > FICIs > 1.06) and a synergistic effect of the combination of robenidine/PMBN (0.5 < FICI) were obtained. DRIs of robenidine were significantly increased in the presence of both EDTA and PMBN from 2- to 2048-fold. Robenidine exhibited antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, in the presence of sub-inhibitory concentrations of either EDTA or PMBN. Robenidine also demonstrated potent antibacterial activity against multidrug-resistant Gram-positive pathogens and all Gram-negative pathogens isolated from cases of canine otitis externa in the presence of EDTA. Robenidine did not demonstrate antibiofilm activity against Gram-positive and Gram-negative bacteria. EDTA facilitated biofilm biomass degradation for both Gram-positives and Gram-negatives. The addition of robenidine to EDTA was not associated with any change in the effect on biofilm biomass degradation. The combination of robenidine with EDTA or PMBN has potential for further exploration and pharmaceutical development, such as incorporation into topical and otic formulations for animal and human use.
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spelling doaj.art-4e5765f60e1d4ec9ab499deef9c9a0992022-12-21T17:43:32ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2019-04-011010.3389/fmicb.2019.00837432309In vitro Antimicrobial Activity of Robenidine, Ethylenediaminetetraacetic Acid and Polymyxin B Nonapeptide Against Important Human and Veterinary PathogensManouchehr Khazandi0Hongfei Pi1Wei Yee Chan2Abiodun David Ogunniyi3Jowenna Xiao Feng Sim4Henrietta Venter5Sanjay Garg6Stephen W. Page7Peter B. Hill8Adam McCluskey9Darren J. Trott10Australian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, AustraliaAustralian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, AustraliaAustralian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, AustraliaAustralian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, AustraliaSchool of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA, AustraliaSchool of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA, AustraliaSchool of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA, AustraliaNeoculi Pty Ltd., Burwood, VIC, AustraliaAustralian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, AustraliaChemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, AustraliaAustralian Centre for Antimicrobial Resistance Ecology, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, AustraliaThe emergence and global spread of antimicrobial resistance among bacterial pathogens demand alternative strategies to treat life-threatening infections. Combination drugs and repurposing of old compounds with known safety profiles that are not currently used in human medicine can address the problem of multidrug-resistant infections and promote antimicrobial stewardship in veterinary medicine. In this study, the antimicrobial activity of robenidine alone or in combination with ethylenediaminetetraacetic acid (EDTA) or polymyxin B nonapeptide (PMBN) against Gram-negative bacterial pathogens, including those associated with canine otitis externa and human skin and soft tissue infection, was evaluated in vitro using microdilution susceptibility testing and the checkerboard method. Fractional inhibitory concentration indices (FICIs) and dose reduction indices (DRI) of the combinations against tested isolates were determined. Robenidine alone was bactericidal against Acinetobacter baumannii [minimum inhibitory concentrations (MIC) mode = 8 μg/ml] and Acinetobacter calcoaceticus (MIC mode = 2 μg/ml). Against Acinetobacter spp., an additivity/indifference of the combination of robenidine/EDTA (0.53 > FICIs > 1.06) and a synergistic effect of the combination of robenidine/PMBN (0.5 < FICI) were obtained. DRIs of robenidine were significantly increased in the presence of both EDTA and PMBN from 2- to 2048-fold. Robenidine exhibited antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, in the presence of sub-inhibitory concentrations of either EDTA or PMBN. Robenidine also demonstrated potent antibacterial activity against multidrug-resistant Gram-positive pathogens and all Gram-negative pathogens isolated from cases of canine otitis externa in the presence of EDTA. Robenidine did not demonstrate antibiofilm activity against Gram-positive and Gram-negative bacteria. EDTA facilitated biofilm biomass degradation for both Gram-positives and Gram-negatives. The addition of robenidine to EDTA was not associated with any change in the effect on biofilm biomass degradation. The combination of robenidine with EDTA or PMBN has potential for further exploration and pharmaceutical development, such as incorporation into topical and otic formulations for animal and human use.https://www.frontiersin.org/article/10.3389/fmicb.2019.00837/fullrobenidinecombinationantimicrobialcanine otitis externaEDTA
spellingShingle Manouchehr Khazandi
Hongfei Pi
Wei Yee Chan
Abiodun David Ogunniyi
Jowenna Xiao Feng Sim
Henrietta Venter
Sanjay Garg
Stephen W. Page
Peter B. Hill
Adam McCluskey
Darren J. Trott
In vitro Antimicrobial Activity of Robenidine, Ethylenediaminetetraacetic Acid and Polymyxin B Nonapeptide Against Important Human and Veterinary Pathogens
Frontiers in Microbiology
robenidine
combination
antimicrobial
canine otitis externa
EDTA
title In vitro Antimicrobial Activity of Robenidine, Ethylenediaminetetraacetic Acid and Polymyxin B Nonapeptide Against Important Human and Veterinary Pathogens
title_full In vitro Antimicrobial Activity of Robenidine, Ethylenediaminetetraacetic Acid and Polymyxin B Nonapeptide Against Important Human and Veterinary Pathogens
title_fullStr In vitro Antimicrobial Activity of Robenidine, Ethylenediaminetetraacetic Acid and Polymyxin B Nonapeptide Against Important Human and Veterinary Pathogens
title_full_unstemmed In vitro Antimicrobial Activity of Robenidine, Ethylenediaminetetraacetic Acid and Polymyxin B Nonapeptide Against Important Human and Veterinary Pathogens
title_short In vitro Antimicrobial Activity of Robenidine, Ethylenediaminetetraacetic Acid and Polymyxin B Nonapeptide Against Important Human and Veterinary Pathogens
title_sort in vitro antimicrobial activity of robenidine ethylenediaminetetraacetic acid and polymyxin b nonapeptide against important human and veterinary pathogens
topic robenidine
combination
antimicrobial
canine otitis externa
EDTA
url https://www.frontiersin.org/article/10.3389/fmicb.2019.00837/full
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