The effect of chlorhexidine on the electrophoretic mobility, cytoplasmic constituents, dehydrogenase activity and cell walls of <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>

Hugo, W. B.; Longworth, A R

doi:10.1111/j.2042-7158.1966.tb07935.x

Cited by 179 publications

(84 citation statements)

References 15 publications

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“…This was evident when concentrations that are considered to achieve membrane permeabilization (ADBAC, Ͼ9 g/ml [Ͼ0.0278 mM]; DDAC, Ͼ4.5 g/ml [Ͼ0.0138 mM]) and catastrophic membrane collapse (ADBAC, 15 g/ml [0.0463 mM]; DDAC, 12 g/ml [0.0368 mM]) were achieved. It was also evident that cells exposed to bactericidal concentrations of ADBAC and DDAC immediately released leakage markers, albeit in different quantities; internal pool material was released to completion within short exposure times, exhibiting actions similar to those of chlorhexidine (24). Concentrations that induced potassium leakage only were not evident, even at concentrations that appeared to inhibit bacterial growth for ADBAC and DDAC.…”

Section: Fig 7 Leakage Of Potassium (}) and 260-nm-absorbing (■) Mamentioning

confidence: 86%

“…DDAC possessed an H (high) uptake isotherm, and only very low levels of residual biocide would be free to interact with 260-nm-absorbing material; hence, no concentration effects were observed. Hugo and Longworth (24) previously found that secondary leakage from cells was reduced due to the inhibition of autolytic enzymes by chlorhexidine. It was also believed that the cell surface or the cytoplasmic membrane congealed, preventing leakage.…”

Section: Fig 7 Leakage Of Potassium (}) and 260-nm-absorbing (■) Mamentioning

confidence: 99%

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Action of Disinfectant Quaternary Ammonium Compounds against Staphylococcus aureus

Ioannou¹,

Hanlon

Denyer

2007

Antimicrob Agents Chemother

330

227

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Mode-of-action studies concluded that alkyldimethylbenzylammonium chloride (ADBAC) (a blend of C 12 , C 14 and C 16 alkyl homologues) and didecyldimethylammonium chloride (DDAC) are both membrane-active agents, possessing subtly different modes of action reflecting early cell interactions against Staphylococcus aureus. ADBAC and DDAC exhibited similar MIC behaviors from 0.4 ppm to 1.8 ppm over an inoculum range of 1 ؋ 10 5 to 1 ؋ 10 9 CFU/ml at 35°C. For ADBAC and DDAC, an increased rapidity of killing against S. aureus (final concentration, 2 ؋ 10 9 CFU/ml) was observed at 35°C compared to 25°C. Concentration exponents () for killing were <2.5 for both agents, and temperature influenced the value. Examination of leakage and kill data suggested that a single leakage marker was not indicative of cell death. ADBAC and DDAC possessed Langmuir (L4) and high-affinity (H3/4) uptake isotherms, respectively. ADBAC molecules formed a single monolayer of coverage of cells at the end of primary uptake, and DDAC formed a double monolayer. Rapid cell leakage occurred at bactericidal concentrations, with total depletion of the intracellular potassium and 260-nm-absorbing pools released in this strict order. Autolysis was observed for ADBAC and DDAC at concentrations of 9 g/ml (0.0278 mM and 0.0276 mM, respectively) and above, together with the depletion of approximately 30% of the internal potassium pool. Autolysis contributed to ADBAC and DDAC lethality, although high biocide concentrations may have inhibited autolytic enzyme activity.

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Section: Fig 7 Leakage Of Potassium (}) and 260-nm-absorbing (■) Mamentioning

confidence: 86%

Section: Fig 7 Leakage Of Potassium (}) and 260-nm-absorbing (■) Mamentioning

confidence: 99%

Action of Disinfectant Quaternary Ammonium Compounds against Staphylococcus aureus

Ioannou¹,

Hanlon

Denyer

2007

Antimicrob Agents Chemother

330

227

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“…The primary mechanism of action of this biocide is membrane disruption, causing concentration-dependent growth inhibition and cell death (18). Secondary interactions causing inhibition of proteolytic and glycosidic enzymes may also be significant (15).…”

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confidence: 99%

Effects of a Chlorhexidine Gluconate-Containing Mouthwash on the Vitality and Antimicrobial Susceptibility of In Vitro Oral Bacterial Ecosystems

McBain

Bartolo

Catrenich

et al. 2003

Appl Environ Microbiol

119

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Oral bacterial microcosms, established using saliva inocula from three individuals, were maintained under a feast-famine regime within constant-depth film fermenters. Steady-state communities were exposed four times daily, postfeeding, to a chlorhexidine (CHX) gluconate-containing mouthwash (CHXM) diluted to 0.06% (wt/vol) antimicrobial content. The microcosms were characterized by heterotrophic plate counts and PCRdenaturing gradient gel electrophoresis (DGGE). CHXM caused significant decreases in both total anaerobe and total aerobe/facultative anaerobe counts (P < 0.05), together with lesser decreases in gram-negative anaerobes. The degree of streptococcal and actinomycete inhibition varied considerably among individuals. DGGE showed that CHXM exposure caused considerable decreases in microbial diversity, including marked reductions in Prevotella sp. and Selenomonas infelix. Pure-culture studies of 10 oral bacteria (eight genera) showed that Actinomyces naeslundii, Veillonella dispar, Prevotella nigrescens, and the streptococci were highly susceptible to CHX, while Lactobacillus rhamnosus, Fusobacterium nucleatum, and Neisseria subflava were the least susceptible. Determination of the MICs of triclosan, CHX, erythromycin, penicillin V, vancomycin, and metronidazole for microcosm isolates, before and after 5 days of CHXM exposure, showed that CHXM exposure altered the distribution of isolates toward those that were less susceptible to CHX (P < 0.05). Changes in susceptibility distributions for the other test agents were not statistically significant. In conclusion, population changes in plaque microcosms following repeated exposure to CHXM represented an inhibition of the most susceptible flora with a clonal expansion of less susceptible species.Chlorhexidine (CHX), a cationic bis-biguanide biocide with low mammalian toxicity and broad-spectrum antibacterial (6) activity, was first described in 1954 (5). The primary mechanism of action of this biocide is membrane disruption, causing concentration-dependent growth inhibition and cell death (18). Secondary interactions causing inhibition of proteolytic and glycosidic enzymes may also be significant (15). With respect to dental hygiene applications, the cationic nature of CHX enables it to bind to tooth surfaces and oral mucosa, reducing pellicle formation and increasing substantivity through controlled release of the agent (2). The efficacy of CHX in reducing oral bacterial viability (14,36,42), strongly inhibiting plaque regrowth, and preventing gingivitis (25) has been demonstrated in many studies (7). Relatively few investigations have considered longer-term effects of CHX use. An early study, however, demonstrated that oral treatment of human volunteers with CHX resulted in a 30 to 50% reduction in total bacterial counts with an associated reduction in counts of Streptococcus mutans (38).Recent reports have demonstrated that the chlorinated diphenylether antibacterial triclosan (TCS) can select for mutants in the FabI gene of Escherichia coli at sublethal co...

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“…CHX is a positively charged hydrophobic and lipophilic molecule that attaches to negatively charged phosphate groups on the cell wall (57), leading to changes in the osmotic balance of the cell (58,59). The antimicrobial activity of CHX depends on the pH (optimum pH of approximately 5.5-7) (60) and on the concentration of the solution (14).…”

Section: Chlorhexidine Chxmentioning

confidence: 99%

Consideration of the Therapeutic Potential of Irrigants in Endodontic Therapy

Nogo-Živanović

Bjelović

Ivanović

et al. 2018

Serbian Journal of Experimental and Clinical Research

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The effect of chlorhexidine on the electrophoretic mobility, cytoplasmic constituents, dehydrogenase activity and cell walls of Escherichia coli and Staphylococcus aureus

Cited by 179 publications

References 15 publications

Action of Disinfectant Quaternary Ammonium Compounds against Staphylococcus aureus

Action of Disinfectant Quaternary Ammonium Compounds against Staphylococcus aureus

Effects of a Chlorhexidine Gluconate-Containing Mouthwash on the Vitality and Antimicrobial Susceptibility of In Vitro Oral Bacterial Ecosystems

Consideration of the Therapeutic Potential of Irrigants in Endodontic Therapy

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