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Biomedical subjects

D J Stickler

Publications and source records attributed to D J Stickler.

64 records · Page 4Linked to original sources

Chlorhexidine resistance and the lipids of Providencia stuartii.

The lipid composition of Providencia stuartii has been shown to resemble closely that of Proteus mirabilis. The ability of some Pv, stuartii strains to survive exposure to high concentrations of the antiseptic chlorhexidine could not be explained in terms of differences in lipid content between sensitive and resistant strains. In addition, resistance could not be attributed to either reduced adsorption of the antiseptic or to its gross enzymic degradation.

Adsorption↗

Sensitivity of urine-grown cells of Providencia stuartii to antiseptics.

Urine-grown cultures of 23 clinical isolates of Gram-negative bacteria having a range of minimum inhibitory concentration values for chorhexidine were challenged with various concentrations of this antiseptic. The results suggest that cells of Providencia stuartii, in particular, exhibit a considerable degree of resistance to chlorhexidine under these conditions, concentrations of up to 10 000--20 000 microgram/ml of urine being necessary to produce complete loss of viability of such cultures. Of the other two antiseptics tested, phenoxyethanol proved to be the more effective, the recommended use concentration of 2% v/v producing reductions in viable counts of greater than six logarithms in all the strains examined. It is suggested that phenoxyethanol may be a suitable alternative to the cationic agents for use in antiseptic policies for bladder management of urinary tract infections with Providencia stuartii.

Anti-Infective Agents, Local↗

Sensitivity of Providence to antiseptics and disinfectants.

Seventy isolates of Providence were obtained from urinary tract infections in patients from five hospitals. They were all identified as Providence B (Providencia stuartii). A typing system was devised for these organisms based on their production of and sensitivity to bacteriophage and bacteriocins. Using this system, 27 distinct strains were recognized, and it was clear that many patients had been infected with the same strain. The minimum inhibitory concentrations of six antiseptics and disinfectants for these strains were determined. Many of the strains were up to 300-fold more resistant to the cationic antiseptics chlorhexidine, cetrimide, and Resiguard than the control strain Escherichia coli NCTC 10418. The sensitivities of the Providence strains to Hycolin, glutaraldehyde, and phenyl mercuric nitrate, however, were similar to those of the control organism. There were significant correlations between the sensitivities of the strains to the three cationic antiseptics. The loss of chlorhexidine resistance from a Providence strain after exposure of the cells to N-methyl-N' nitro N nitrosoguanidine resulted in a concomitant loss of resistance to cetrimide and Resiguard, but there was no significant increase in the sensitivity of the mutants to the other three antibacterials.

Anti-Infective Agents, Local↗

Chlorhexidine resistance in Proteus mirabilis.

A total of 104 clinical isolates of Pr. mirabilis from three hospitals were screened for their sensitivity to chlorhexidine. The minimum inhibitory concentrations of the antiseptic for these strains ranged from 10 to 800 mug/ml. Two strains sensitive to 20 mug of chlorhexidine/ml were adapted to resistance by growth in subinhibitory concentrations of the antiseptic, their MIC values increasing to 200 and 800 mug/ml. These derived strains exhibited slightly reduced sensitivity to cetrimide and benzalkonium chloride. The chlorhexidine-resistant clinical isolates also exhibited this partially decreased sensitivity to the quaternary ammonium compounds. Both the chlorhexidine-sensitive and -resistant strains were uniformly sensitive to chloroxylenol (Dettol), glutaraldehyde, and 2-phenoxyethanol.

Benzalkonium Compounds↗