The Adsorption of Cetyltrimethylammonium Bromide by Bacteria, its Action in Releasing Cellular Constituents and its Bactericidal Effects

S U M M A R YWhen Gram-negative cell walls were damaged by lysozyme and ethylenediaminetetra-acetic acid (EDTA) in tris buffer, tris played an active role through its action as an organic cation. Other organic cations such as aliphatic amines and quaternary ammonium compounds were more effective than tris in modifying the cell wall and making it permeable to other solutes. The most effective organic cations had one C,, to CI6 alkyl chain. At ~H I o , EDTA roo pg./ml and N,N-dimethyldodecylamine (DDA) 2.5 ,ug./ml. modified the cell wall of Escherichia coli so as to permit a more than 99.99 % kill by 20,ug.fml. of a zwitterionic surface active agent, a-hydroxy-3-(dimethylhexadecylammonio) propane-I -sulphonate (HAPS), in 10 min. at 37'. At these concentrations, the individual compounds were bactericidally ineffective. Four other Gram-negative species were shown to be similarly susceptible to killing by this system. Together, EDTA and DDA appeared to remove surface components of the Gram-negative cell wall. Alone, DDA and other organic cations removed somatic antigens from the cell wall.

Section: Discussionmentioning

confidence: 99%

Effects of Organic Cations on the Gram-negative Cell Wall and Their Bactericidal Activity with Ethylenediaminetetra-acetate and Surface Active Agents

Voss

1967

“…Cetyltrimethylammonium bromide (CTAB) is known to disorganize the cytoplasmic membrane of bacteria (Salton, 1951) and was tested for its effects on the osmotic lysis of Vibrio costicolus. CTAB was added to the stock suspension 2 min.…”

Section: J H B Christian and M Ingrammentioning

confidence: 99%

Lysis of Vibrio costicolus by Osmotic Shock

Christian

Ingram

1959

SUMMARY : Suspensions of the halophilic organism Vibrio costicolus lysed when subjected to sufficient osmotic shock; this was revealed as a marked fall in optical density. Organisms in the logarithmic phase of growth, grown in media containing M-NaCl, when suspended in NaCl or LiCl solutions with concentrations M or lower lysed when the concentration was below 0.33 M : when the organisms were suspended similarly in KCl or NH,CI solutions, lysis began at a concentration above 0 . 8~.Older organisms were more resistant to lysis. Lysis was little affected by replacement of chloride by other univalent anions, by pH values from 4 to 10 or by previous incubation with M-mercuric chloride. Addition of cetyltrimethylammonium bromide (200 pg./ml.) increased resistance to lysis in both NaCl and KCl solutions, Organisms grown in media of NaCl concentrations ranging from 0.5 to 3 . 0~ began to lyse a t a NaCl concentration one-third of that present during growth. Organisms suspended in NaCl solutions of one-half the concentration in which they had been grown equilibrated promptly to the new environment ; this was shown by a decrease of 5 0 % in the salt concentration at which lysis then began. When organisms were transferred to salt concentrations higher than that of the growth medium, the osmotic sensitivity was not affected. It is concluded that the osmotic status of these organisms is controlled chiefly by small ions or molecules which leak rapidly from the cells on transfer to dilute environments.Many types of bacteria lyse when transferred from concentrated growth media to more dilute solutions or to water, and this behaviour is particularly common among halophilic strains. Robinson & Katznelson (1953) noted that the extremely halophilic Pseudomonus salinaria, grown in a medium containing 16 yo (w/v) NaC1, underwent rapid plasmoptysis on transfer to 1 , 2 or 4 yo NaCl and showed some deterioration of structure in 8 % NaC1. However, no attempts appear to have been made to study quantitatively the degree of lysis resulting from osmotic shock. Christian & Ingram (1959) found that the freezing-point depression of heated bacteria was similar to that of their growth medium over a wide range of salt concentra.tions. It was of interest, therefore, to investigate the relationship between the osmotic sensitivity of such organisms and the salt concentration of the environment. This paper describes a technique for measurement of osmotic lysis, and reports the effects of a number of factors on the osmotic sensitivity of a moderate halophile, Vibrio costicolus. METHODS Organism.The test organism was a strain of Vibrio costicolus kindly supMedia. The organism was grown in liquid media containing 0.5% (w/v)

“…Antiseptics and detergents, under certain conditions promote the leakage of cell constituents from bacteria (Hotchkiss, 1946; Gale & Taylor, 1947; Salton, 1950Salton, , 1951 and enable sugars to enter cells more readily (Deere, 1939). Evidence has also been obtained that the enzymes concerned with the utilization of certain sugars are intracellular (Deere, 1939), whereas those concerned in the oxidation of organic acids may be a t or near the cell surface (Quastel, 1926).…”

Section: W B Hugo and H E Streetmentioning

confidence: 99%

The Effect of Phenol, 2-Phenoxyethanol and Cetyltrimethylammonium Bromide on the Oxidation of various Substrates by Escherichia coli

Hugo

Street

1952

SUMMARY : Effects of phenol, 2-phenoxyethanol and cetyltrimethylammonium bromide on the oxygen uptake of suspensions of Escherichia coli supplied with various single oxidizable substrates were examined. Phenol and 2-phenoxyethanol at low concentrations caused a stimulation of oxygen uptake in the presence of mannitol, glucose or lactose which was not associated with an increase in viable count, no stimulation with glycerol, and a retarded oxygen uptake with lactate, succinate or pyruvate. At higher concentrations phenol and 2-phenoxyethanol caused a retardation of oxygen uptake with all substrates, the degree varying with the substrate. Cetyltrimethylammonium bromide was toxic a t very low concentrations and no stimulation of oxygen uptake by low concentrations or differential response in presence of different substrates was found.Phenol, 2-phenoxyethanol (phenoxetol) and cetyltrimethylammonium bromide (cetrimide) chosen as representative of anionic, non-ionizing and cationic antiseptics respectively, were examined for their effect on respiratory mechanisms of Esch. coli as shown by the effect on oxygen uptake in presence of various substrates. EXPERIMENTALOrganism. The organism used was Esch. coli NCTC 5934. It was subcultured in nutrient broth, and freeze-dried (Proom & Hemmons, 1949). Culture medium. Nutrient broth was prepared by the tryptic digestion of lean meat; after autoclaving it had a pH of 7.2-7-4. It was solidified when required by the addition of 2 yo agar.Chemicals. The 2-phenoxyethanol (phenoxetol) was supplied by Nipa Laboratories Ltd., Cardiff. The cetyltrimethylammonium bromide (cetrimide) was a commercial sample which, assayed by the method of The British Pharmaceutical Codex (1949), contained 84.4 % (w/w) of CI9H3,( CH,),NBr.The sugars and mannitol used were of bacteriological quality as supplied by Messrs T. Kerfoot Ltd.; sodium pyruvate was prepared by the method of Robertson (1942); all other chemicals were of A.R. quality.Phosphate buffirs. 0.1 M or 0.05 M-KH,PO, and Na2HP04. 12H20 were mixed immediately before use, to give a pH value of 7.0 (electrometric). Ringer's solution was prepared according to Wilson (1922) and sterilized by autoclaving; final pH c. 7.5.Bacterial suspensions. The contents of a tube of freeze-dried material were reconstituted with nutrient broth, grown at 37" for 18 hr., then subcultured * Present address :