Sodium Hypochlorite Stress in Enterococcus faecalis : Influence of Antecedent Growth Conditions and Induced Proteins

Abstract

Compared with exponential growing bacteria, carbohydrate-starved cells of Enterococcus faecalis exhibit a high level of resistance to sodium hypochlorite with maximal resistance observed in cultures entering stationary phase. Chloramphenicol treatment, at various stages of growing phase, does not abolish the hypochlorite resistance of starved cells. However, Enterococcus faecalis conditioned by low sodium hypochlorite concentrations does not develop tolerance towards a lethal dose of the disinfectant. Two-dimensional gel analysis shows that protein synthesis is drastically turned off by hypochlorite treatment, whereas synthesis of a few proteins is enhanced by a low concentration of this chemical agent.

Altered Protein Expression of Streptococcus oralis Cultured at Low pH Revealed by Two-Dimensional Gel Electrophoresis

“…The overwhelming difference between the growth conditions was the initial pH of the media, however, although it maybe that the difference in growth rate had an effect on the expression of some of the proteins described here and that biofilm or continuous culture grown cells will also express different proteins. Numerous studies have used the high resolving power of 2-D electrophoresis to monitor changes in protein expression during the adaptation of microorganisms to environmental stress (4,22,28,30,41,44). We have used this technique to investigate the regulation of gene product expression of S. oralis grown under conditions of differing pH and used peptide mass fingerprinting to identify those proteins with altered expression.…”

Enterococci in the Environment

“…Furthermore, carbohydrate starvation can enhance resistance to multiple stressors, including heat, oxidative stress, acid, ethanol, and sodium hypochlorite (122,124,146,199). One protein in particular (gls24), belonging to the class A starvation proteins in E. faecalis (synthesized in both growing and resting cells but differentially expressed during starvation) (123), was overexpressed under both starvation conditions mentioned above (122,123).…”

Effects of Dentin on the Antimicrobial Properties of Endodontic Medicaments

“…With systemically used antibiotics this is the correct procedure, and the practice is based on decades of extensive testing in vitro and in vivo, with a proven correlation between the in vitro measurements and the in vivo effectiveness. It is generally known that (ecologic) stress changes the susceptibility pattern of many microbes; increased stress usually contributes to increased resistance to one or several chemical agents (73)(74)(75). Glucose starvation increased the resistance of E. faecalis to sodium hypochlorite, whereas pretreatment with sublethal concentrations of sodium hypochlorite did not cause any changes in the susceptibility of E. faecalis to this substance (74).…”

“…It is generally known that (ecologic) stress changes the susceptibility pattern of many microbes; increased stress usually contributes to increased resistance to one or several chemical agents (73)(74)(75). Glucose starvation increased the resistance of E. faecalis to sodium hypochlorite, whereas pretreatment with sublethal concentrations of sodium hypochlorite did not cause any changes in the susceptibility of E. faecalis to this substance (74). Portenier et al (76) conducted a series of experiments in which E. faecalis cells at different growth phases were challenged by calcium hydroxide, CHX, or sodium hypochlorite.…”