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THE ASSESSMENT OF RELATIVE BACTERICIDAL ACTIVITY AMONG CERTAIN PHENOLS BY A PHYSICAL METHOD
Author(s) -
MAURICE P.
Publication year - 1957
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.1365-2672.1957.tb04525.x
Subject(s) - phenol , chemistry , phenols , distilled water , turbidity , phosphate , potassium , suspension (topology) , inorganic chemistry , nuclear chemistry , chromatography , organic chemistry , oceanography , mathematics , homotopy , pure mathematics , geology
SUMMARY: The addition of phenol, various alkyl phenols, or CTAB to a suspension of E. coli in distilled water caused the optical density to increase, the change being more marked as the concentration of a given compound was raised. Families of curves of similar shape were obtained with all the compounds when optical density was plotted against time for different concentrations, and figures expressing the activity relative to that of 1·2% phenol were obtained by dividing the concentration which produced the same curve as that concentration of phenol, into 1·2. These figures were very similar to those obtained for the bactericidal effects of the compounds relative to 1·2% phenol, using an ‘end‐point’ method. The presence of the chlorides of mono‐ and divalent metals at 10 −4 M, or of the sulphates of trivalent metals at 10 −5 M, did not affect the turbidity reaction, but higher concentrations of monovalent metal salts, e.g. 2 × 10 −2 M phosphate buffer (potassium) at pH 6·7, markedly retarded the change due to phenol. That concentration of the buffer also greatly reduced the bactericidal activity of 1·2% phenol. Much of the turbidity increase, however, occurred after all the cells of the suspensions had been killed, with phenol concentrations over 1·0%.