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Biomedical subjects

A D Russell

Publications and source records attributed to A D Russell.

At least 145 records · Page 8Linked to original sources
PubMed1986

Susceptibility of porin- and lipopolysaccharide-deficient strains of Escherichia coli to some antiseptics and disinfectants.

The sensitivities of some outer membrane protein (Omp) and/or lipopolysaccharide (LPS)-defective mutants of Escherichia coli to chlorhexidine and some quaternary ammonium compounds (QACs) were examined. Wild-type strains, with no defect in Omp or LPS were the most resistant to QACs, whereas LPS-deficient strains were the most sensitive. As expected, QAC resistance could not be related to the presence or absence of any specific porin(s). Chlorhexidine was highly active against all strains, inhibitory concentrations lying within the narrow range of 1 and 2 mg l-1.

Anti-Bacterial Agents↗
PubMed1986

Resistance of Providencia stuartii to chlorhexidine: a consideration of the role of the inner membrane.

Spheroplasts of three strains of Providencia stuartii (one sensitive, one moderately sensitive and one resistant to chlorhexidine) were induced by cefoxitin, glycine or a lysozyme-tris-EDTA combination, and their susceptibility to chlorhexidine-induced lysis investigated. Maximum lysis of spheroplasts occurred at a low (2.5-5 micrograms/ml) concentration of chlorhexidine and was greatest with the most sensitive strain, Pv2. The possible role of the inner membrane in chlorhexidine resistance is considered in the light of the findings obtained.

Bacteriolysis↗
PubMed1986

Reversal of the surface effects of chlorhexidine diacetate on cells of Providencia stuartii.

Chlorhexidine diacetate (CHA) increased the hydrophobicity of the cell surface of cells of three strains of Providencia stuartii. Removal of at least some of the CHA from the cells by washing them with an appropriate antidote partially reversed the hydrophobicity-increasing action of the biguanide. The effects of other treatments on cell surface hydrophobicity were examined with these strains and, for comparison, with two strains each of Escherichia coli and Pseudomonas aeruginosa: ethylenediamine tetraacetic acid affected all strains, although not to the same extent, whereas thermal injury (55 degrees C) produced marked changes only with the two E. coli strains.

Cell Membrane↗
PubMed1985

Antiseptic-induced changes in the cell surface of a chlorhexidine-sensitive and a chlorhexidine-resistant strain of Providencia stuartii.

The effects of chlorhexidine diacetate and benzalkonium chloride on the cell surface of a chlorhexidine-sensitive (Pv 2) and a chlorhexidine-resistant (Pv 67) strain of Providencia stuartii are described. Low concentrations of chlorhexidine diacetate (10 mg/l and upwards) increased the hydrophobicity of Pv 2, whilst having little effect on Pv 67. Both strains were resistant to benzalkonium chloride but a concentration as low as 2 mg/l induced a significant increase in hydrophobicity in Pv 2, with 25-50 mg/l needed to induce a similar type of increase in Pv 67. The possible nature of the resistance is discussed.

Anti-Infective Agents, Local↗
PubMed1982

The influence of glucose, ammonium and magnesium availability on the production of protease and bacitracin by Bacillus licheniformis.

Bacillus licheniformis was cultivated in a range of defined media varying in both the nature of the growth-limiting component and the concentration of excess nutrients. The compositions of the media were such as to ensure that the final absorbance (A430) of the culture was the same in each case. Samples taken during the stationary phase were assayed for their content of extracellular serine protease and bacitracin. The nature of the growth-limiting nutrient had a profound effect on the amounts of these products formed while those components which were present in excess also exerted an influence in proportion to their concentration. Thus, for example, a four-fold increase in serine protease production occurred when ammonium replaced glucose as the growth-limiting nutrient. Serine protease and bacitracin production responded differently to these varying cultural conditions suggesting they are subject to separate control mechanisms. The results are discussed in relation to the need for rigorously controlled cultural conditions during physiological studies of this nature.

Ammonia↗