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Changes in the biocide susceptibility of Staphylococcus epidermidis and Escherichia coli cells associated with rapid attachment to plastic surfaces
Author(s) -
; Das,
Bhakoo,
; Jones,
Frédéric Gilbert
Publication year - 1998
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.1998.00422.x
Subject(s) - biocide , biofilm , microbiology and biotechnology , peracetic acid , cetrimide , minimum inhibitory concentration , staphylococcus epidermidis , optical density , chemistry , biguanide , staphylococcus aureus , bacteria , bacterial growth , agar , biology , antimicrobial , biochemistry , organic chemistry , medicine , genetics , dentistry , chlorhexidine , metformin , endocrinology , ophthalmology , diabetes mellitus , hydrogen peroxide
Differences in opacity between wells of a microtitre plate containing different volumes of inoculated growth medium reflected planktonic growth without any contribution from cells attached at the well surface. Simple algebra and a knowledge of the dependence of optical density upon sample path length (volume) for suspensions of differing cell density enables the generation of growth curves for attached populations (biofilms). In this manner, minimum inhibitory concentrations (MICs) were determined at various stages of growth (0–20 h), both for cells growing attached to the bases of the plate wells and, simultaneously, for cells growing in suspension above them. Biocides included cetrimide, polyhexamethylene biguanide, peracetic acid, phenoxyethanol and chloroxylenol. Results, expressed as planktonic:biofilm MIC ratios, showed susceptibility to change, not only as a function of attachment and biofilm formation, but also with respect to the nature of the chemical agent. In some instances, changes in susceptibility greater than twofold occurred immediately on attachment and could occur in the presence of biocide concentrations which exceeded the MIC.