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Resistance of Pseudomonas aeruginosa to isothiazolone
Author(s) -
Brözel V.S.,
Cloete T.E.
Publication year - 1994
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1994.tb01655.x
Subject(s) - pseudomonas aeruginosa , microbiology and biotechnology , extracellular , chemistry , pseudomonadaceae , minimum inhibitory concentration , bacterial outer membrane , bacteria , lipopolysaccharide , biofilm , pseudomonadales , pseudomonas , biochemistry , biology , escherichia coli , antimicrobial , gene , immunology , genetics
This investigation was to determine whether Pseudomonas aeruginosa could acquire resistance to the bactericide isothiazolone, and what the nature of such a resistance mechanism would be. The Pseudomonas was cultured in nutrient‐limited broth in the presence of sub‐inhibitory concentrations of isothiazolone (a mixture of 1.15% 5‐chloro‐ N ‐methylisothiazolone (CMIT) and 0.35% N ‐methylisothiazolone (MIT)). Three cultures tested in parallel adapted gradually during exposure for 15 d from an initial minimum inhibitory concentration (MIC) of 300 μl 1 ‐1 to 607 μl ‐1 . The three parallel cultures adapted at similar rates, so the adaptation was not ascribed to mutation but to a specific mechanism. Resistant cells did not produce any extracellular isothiazolone‐quenching compounds nor undergo detectable alterations in their lipopolysaccharide layer. In wild cells, a 35 kDa outer membrane protein (protein T) was detectable, whereas resistant cells lacked this protein. Production of protein T was suppressed within 24 h of exposure to isothiazolone. It was still suppressed after 72 h of growth in isothiazolone‐free medium. It is proposed that Ps. aeruginosa acquires resistance to isothiazolone by a process of adaptation where the outer membrane protein T is suppressed.