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Development of a protocol for predicting bacterial resistance to microbicides

Knapp, Laura, Amézquita, Alejandro, McClure, Peter, Stewart, Sara and Maillard, Jean-Yves ORCID: 2015. Development of a protocol for predicting bacterial resistance to microbicides. Applied and Environmental Microbiology 81 (8) , pp. 2652-2659. 10.1128/AEM.03843-14

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Regulations dealing with microbicides in Europe and the United States are evolving and now require data on the risk of resistance development in organisms targeted by microbicidal products. There is no standard protocol to assess the risk of resistance development to microbicidal formulations. This study aimed to validate the use of changes in microbicide and antibiotic susceptibility as initial markers for predicting microbicide resistance and cross-resistance to antibiotics. Three industrial isolates (Pseudomonas aeruginosa, Burkholderia cepacia, Klebsiella pneumoniae) and two Salmonella enterica serovar Typhimurium strains (SL1344 and 14028S) were exposed to a shampoo, a mouthwash, eye make-up remover and the microbicides contained within these formulations (chlorhexidine digluconate; CHG and benzalkonium chloride; BZC), under realistic, in-use conditions. Baseline and post- exposure data were compared. No significant increases in minimum inhibitory concentration (MIC) or minimum bactericidal concentration (MBC) were observed in any strain after exposure to the three formulations. Increases in the MIC and MBC of CHG and BZC of up to 100-fold were observed in SL1344 and 14028S but were unstable. Changes in antibiotic susceptibility were not clinically significant. The use of MICs and MBCs combined with antibiotic susceptibility profiling and stability testing generated reproducible data that allowed for an initial prediction of microbicide resistance development. These approaches measure characteristics that are directly relevant to the concern over resistance and cross-resistance development following use of microbicides. These techniques are low cost and high-throughput, allowing manufacturers to provide data to support early assessment of risk of resistance development to regulatory bodies promptly and efficiently.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Pharmacy
Subjects: R Medicine > RM Therapeutics. Pharmacology
Publisher: American Society for Microbiology
ISSN: 0099-2240
Date of First Compliant Deposit: 30 March 2016
Last Modified: 17 Nov 2023 16:52

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