Concentrations Of Chlorhexidine Digluconate Research Articles

Identification of norA, qacAB and smr genes and determination of antibiotic and biocide resistance patterns in methicillin-resistant Staphylococcus aureus isolated from Isfahan-Iran

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial infections, which have become a serious problem due to antibiotic resistance. In addition to antibiotic resistance, biocide resistance is also increasing due to the high use of these substances. The aim of this study was to investigate the pattern of antibiotic resistance and the prevalence of biocide resistance genes norA, qacA/B and smr, and to determine the minimum inhibitory concentration of chlorhexidine digluconate (CHG) and benzalkonium chloride (BKC) in MRSA isolates taken from teaching hospitals in Isfahan city, Iran. Materials and Methods: This study was conducted on 63 MRSA isolates collected from teaching hospitals in Isfahan city, Iran. MRSA isolates were identified by performing phenotypic testing and then confirmed by using PCR. The resistance pattern was determined by using disc diffusion method. Broth microdilution method was performed to determine the minimum inhibitory concentration (MIC) of CHG and BKC according to the Clinical and Laboratory Standards Institute (CLSI). The presence of biocide resistance genes was determined by using PCR and the Time kill assay was performed to investigate the lethality of biocides. Results: MRSA isolates had MIC values of 0.5–4 μg/ml for BKC and 0.125–4 μg/ml for CHG. norA was the most common biocide resistance gene among 63 isolates (88.9%), followed by qacAB and smr with 28.6% and 22.2%, respectively. Among the isolates, the highest percentage of resistance belonged to penicillin, erythromycin and doxycycline, respectively. Conclusion: Due to the high prevalence of MRSA isolates in hospitals and the role of this pathogen in nosocomial infections, continuous monitoring of antimicrobial resistance for appropriate antibiotic administration and continuous evaluation of biocide resistance due to the high prevalence of resistance genes and appropriate use of biocides for disinfection, allows us to minimize further prevalence of resistant strains in hospital environments.

Dentine Surface Morphology after Chlorhexidine Application-SEM Study.

Chlorhexidine (CHX) is a widely known and a very popular antibacterial agent that decreases the level of cariogenic bacteria. CHX applied on the cavity surface of dentine may influence adhesive bond strength. The aim of the study was to evaluate the dentine surface after different chlorhexidine digluconate (CHG) application protocols. Different CHG application protocols were introduced. A concentration of 0.2% or 2.0% CHG was applied on the etched or unetched dentine surface for 15 or 30 s, then water rinsed or drained. Scanning electron microscopy (SEM) observations and energy disperse spectrometer (EDS) analysis of the dentine surfaces were performed. The application of 0.2% CHG for 15 s, followed by draining, on either etched or unetched dentine surface effectively removed the smear layer, leaving the surface enriched with CHG deposits. Conclusions: The concentration of CHG and its application time influenced the amount of CHG deposits and the degree of smear layer removal from the dentine surface.

The effect of incorporating different concentrations of chlorhexidine digluconate on the degree of conversion of an experimental adhesive resin.

BackgroundThe aim of this study was to evaluate the effect of chlorhexidine digluconate incorporation on the degree of conversion of an experimental adhesive resin.Material and MethodsThe experimental resin was prepared from 70 wt% bisphenol A glycerolate dimethacrylate, 30 wt% hydroxyethyl methacrylate, silanized SiO2 nanofillers, 0.5% of camphorquinone and ethyl 4-dimethylaminebenzoate (binary photo-initiator system). Five chlorhexidine digluconate concentrations (0, 0.5, 1, 2 and 4 wt%) were then incorporated into the experimental resin. Thirty Potassium Bromide pellets were prepared then divided into six groups (n=5/group), repre¬senting the tested adhesive resins (Single Bond 2, 0, 0.5, 1, 2 and 4 wt% chlohexidine-incorporated experimental adhesive resins), that were applied to the pellets without light-curing (uncured specimens). Another 30 pellets were prepared and treated with the previous materials then light-cured using LED light-curing device (cured specimens). Degree of conversion of the uncured and the cured specimens were evaluated using FTIR analysis.ResultsAdper Single Bond 2 showed the highest degree of conversion mean values followed by 0.5 wt% chlorhexidine concentration then 2 wt% followed by 4 wt% then 1 wt% concentrations, while 0 wt% concentration showed the lowest mean values.ConclusionsChlorhexidine digluconate had slight significant influence on the efficiency of polymerization of the experimental adhesive resin. Key words:Chlorhexidine digluconate, different concentrations, degree of conversion, experimental adhesive resin.

Addition of chlorhexidine gluconate to a glass ionomer cement: a study on mechanical, physical and antibacterial properties.

The objective of this work was to determine the effect of different concentrations of chlorhexidine digluconate (CHX) on setting time, surface hardness, maximum tensile bond strength and antibacterial activity of a glass ionomer cement (GIC). The material used as control was Ketac Molar Easymix GIC. CHX was incorporated into the GIC during its manipulation at concentrations of 0.5, 1.0 and 2.0%. Antimicrobial activity against S. mutans and L. acidophilus was evaluated by means of agar diffusion test. Tensile bond strength data were analyzed statistically using Analysis of variance and Tukey's test. Setting time, Vickers hardness and agar diffusion test were analyzed using Kruskal-Wallis and Mann-Whitney tests at a significance level of 5%. It was observed that adding CHX at concentrations of 1% and 2% increased significantly the setting time of the material (p=0.012 and p=0.003, respectively). There was no significant difference between control and 0.5% CHX groups regarding the setting time. Addition of 2% CHX decreased significantly the surface hardness in relation to the control group (p=0.009), followed by the 1% CHX group (p=0.009). The tensile bond strength of the material also decreased significantly after adding CHX at a concentration of 2% (p=0.001). Addition of CHX promoted formation of an inhibition halo in both bacterial strains for all concentrations. The results showed that the best option for clinical use of GIC with CHX is at 0.5% concentration, since antibacterial activity increased and the physical-mechanical properties remained unchanged.

Enhanced chlorhexidine skin penetration with eucalyptus oil

BackgroundChlorhexidine digluconate (CHG) is a widely used skin antiseptic, however it poorly penetrates the skin, limiting its efficacy against microorganisms residing beneath the surface layers of skin. The aim of the current study was to improve the delivery of chlorhexidine digluconate (CHG) when used as a skin antiseptic.MethodChlorhexidine was applied to the surface of donor skin and its penetration and retention under different conditions was evaluated. Skin penetration studies were performed on full-thickness donor human skin using a Franz diffusion cell system. Skin was exposed to 2% (w/v) CHG in various concentrations of eucalyptus oil (EO) and 70% (v/v) isopropyl alcohol (IPA). The concentration of CHG (μg/mg of skin) was determined to a skin depth of 1500 μm by high performance liquid chromatography (HPLC).ResultsThe 2% (w/v) CHG penetration into the lower layers of skin was significantly enhanced in the presence of EO. Ten percent (v/v) EO in combination with 2% (w/v) CHG in 70% (v/v) IPA significantly increased the amount of CHG which penetrated into the skin within 2 min.ConclusionThe delivery of CHG into the epidermis and dermis can be enhanced by combination with EO, which in turn may improve biocide contact with additional microorganisms present in the skin, thereby enhancing antisepsis.

Effects of drugs on water permeability of erythrocyte membranes

The method of NMR-relaxation with the manganese doping has been applied to study changes of water permeability of red blood cell membranes affected by various concentrations of chlorhexidine digluconate and dimephosphone. It is shown that both investigated substances suppress the water permeability of the red blood cell membrane in a dose-dependent manner. Half-maximum inhibitory effect of studied substances was reached at the concentrations of 9 μM of chlorhexidine and 400 μM of dimephosphone.

Influence of chlorhexidine digluconate concentration and application time on resin–dentin bond strength durability

Although it is known that chlorhexidine application may preserve resin-dentin bonds from degradation, the lowest optimal concentration and application time have yet to be established. This study evaluated the effects of different concentrations of chlorhexidine digluconate and different application times on the preservation of resin-dentin bonds formed using two etch-and-rinse adhesives. In experiment 1, after acid etching, the occlusal demineralized dentin was rewetted either with water or with 0.002, 0.02, 0.2, 2, or 4% chlorhexidine for 60 s. In experiment 2, the surfaces were rewetted with water, or with 0.002% or 2% chlorhexidine for 15 or 60 s. After this, both adhesives and composite resin were applied and light-cured. Bonded sticks (0.8 mm(2)) were tested under tension (0.5 mm min(-1)) immediately or after 6 months of storage in water. Two bonded sticks from each tooth were immersed in silver nitrate and analyzed quantitatively using scanning electron microscopy. Reductions in microtensile bond strengths and higher silver nitrate uptake were observed for both adhesives when the rewetting procedure was performed with water. Stable bonds were maintained for up to 6 months under all chlorhexidine conditions tested, irrespective of the chlorhexidine concentration and application time. The use of 0.002% chlorhexidine for 15 s seems to be sufficient to preserve resin-dentin interfaces over a 6-month period.

Effects of chlorhexidine digluconate and hydrogen peroxide on Porphyromonas gingivalis hemin binding and coaggregation with oral streptococci.

Porphyromonas gingivalis, a gram-negative anaerobe, is one of the major causative agents of periodontal disease. In this study, the effects of chlorhexidine digluconate and hydrogen peroxide on the hemin binding of P. gingivalis and coaggregation of this bacterium with oral streptococci were examined. The pretreatment of P. gingivalis W50 and 381 with chlorhexidine digluconate and hydrogen peroxide increased the hemin binding of these bacteria. The hemin binding of P. gingivalis was increased by the subminimal inhibitory concentration (MIC) of chlorhexidine digluconate. However, concentrations of hydrogen peroxide below the MIC had no effect on the hemin binding of P. gingivalis W50 and 381. Coaggregation of P. gingivalis 381 with Streptococcus oralis ATCC 9811 and Streptococcus gordonii DL1 was diminished by chlorhexidine digluconate. The coaggregation-inhibitory effect was concentration-dependent. Hydrogen peroxide also showed inhibitory effects on the coaggregation of P. gingivalis 381 with S. oralis 9811 and S. gordonii DL1 at concentrations below that used clinically. Concentrations of chlorhexidine digluconate below the MIC inhibited coaggregation. However, concentrations of hydrogen peroxide below the MIC were not effective in reducing the coaggregation of P. gingivalis with oral streptococci. These observations show that chlorhexidine digluconate and hydrogen peroxide could confer variable effects on P. gingivalis hemin binding and coaggregation of this bacterium with oral streptococci.

Biological Treatment of Chlorhexidine Digluconate-Containing Waste Water. III. Effect of Long Time Aeration on the Treatment Efficiency in Batch Activated Sludge Treatment.

The effect of aeration time on the efficiency of batch activated sludge treatment was experimentally investigated to treat wastewater containing higher concentration of CHG (chlorhexidine digluconate) with the activated sludge acclimated to CHG of constant concentration. 2 ppm and 10 ppm CHG-containing wastewater was charged into the aeration vessel keeping activated sludge acclimated to 0.5 ppm CHG-concentration and treated under the different conditions (6 h, 12 h, 22 h) on aeration time for one month and their treatment efficiency were compared with that of control (CHG : 0.5 ppm, aeration : 6h). The results shown were as follows. The treatment efficiency of both 2 ppm and 10 ppm CHG-containing wastewater under the same aeration time as control was remarkably inferior to that of the control. Longer time aeration, however, remarkably improved the treatment efficiency of all of TOD (Total Oxygen Demand), TOC (Total Organic Carbon), COD (Chemical Oxygen Demand), NH4+ and NO3- except TOD, NH4+ and NO3- in case of 10 ppm CHG-containing wastewater. In case of 10 ppm CHG-containing wastewater, long time aeration was effective for the first 5 d after the starting operation, but the treatment efficiency of TOD, NH4+ and NO3- went down suddenly from 6th day and after then the efficiency of TOD by long time aeration was getting lower and lower day by day. Whereas the effect of long time aeration as to NH4+ and NO3- nearly disappeared after 6th day. NO2- was almost absent in effluent during the experiment.

A study of the elimination of chlorhexidine from the oral cavity using a new spectrophotometric method.

A method for the determination of chlorhexidine in saliva is described. The mean recovery rates observed with chlorhexidine digluconate added to saliva in the ranges 5–25,μg/ml and 25–200 μg/ml where 103.6 % and 102.8 % respectively. The lower limit of the method is in the vicinity of 5 μg of chlorhexidine digluconate. The accuracy was found to be ± 3 % and ± 1 % when the concentration of the samples were in the ranges 5–25 μg/ml and 25–200 μg/ml respectively. The method is not specific for chlorhexidine and the amount of interfering material in saliva was found to be equivalent to 3.45 ± 0.54 μg/ml of chlorhexidine digluconate. The rate of elimination of chlorhexidine digluconate from the mouth after one mouthrinse with 20 mg followed approximately the equation describing a process of the first order. The mean values of the half‐times (t/2) and the initial concentrations (Cmax) was found to be 63 ± 11 min and 153 + 27 μg/ml respectively. The concentration of chlorhexidine digluconate was higher than the proposed minimal inhibitory concentration for oral streptococci of 5 μg/ml for approximately 5 hours. The significance of this in relation to the clinical effect of mouthrinsing with chlorhexidine is discussed. The amount of chlorhexidine digluconate swallowed after one mouthrinse was estimated to be approximately 4 mg corresponding to 20 % of the dose.