Concentrations Of Chlorhexidine Gluconate Research Articles

Novel Effects of Chlorhexidine Gluconate on Gram-Positive vs Gram-Negative Microorganisms

Abstract Introduction/Objective Chlorhexidine Gluconate (CHG) is a widely used antiseptic for the skin, oral areas, and cleansing oneself for surgery. Uses of CHG throughout healthcare centers have proven to reduce potential pathogens and lessen risks of central venous catheter blood infections. Gram-positive and gram-negative microorganisms can lead to major diseases such as prostatitis, candidiasis, endocarditis, and more. It is crucial to understand the effects that CHG has on these organisms so we can accurately apply it to treat these various illnesses. It also allows us to better understand the source of surgical site infections (SSIs) and prevent them. Methods/Case Report A minimum bactericidal concentration (MBC) was employed to see how various CHG concentrations (0% (control), 1%, 3%, 5%, 7%, and 9%) would affect the gram-positive (C. albicans and S. aureus) and gram-negative (P. aeruginosa and E. coli) microorganisms. First, a 1.0 McFarland suspension was created for each organism. Then, the various CHG concentration wells for each microorganism would be created within 96 well plates. In each well, there was always 300 μL of solution (containing the McFarland suspension and CHG liquid formula (HibiClensTM). After 4 minutes of CHG exposure in each well, an inoculating loop was used to streak a petri dish. One trial was completed after all concentrations were done for each microoganism. Each trial was incubated for 24 hours and there were a total of 6 trials. Results (if a Case Study enter NA) The substantial results challenged the previously assumed hypothesis that gram- negative microorganisms are more resistant to CHG. The separation between the two types of microorganisms became evident at even the 1% CHG concentration. C. albicans and S. aureus are thriving with averages of approximately 74,333 CFU/mL and 70,333.3 CFU/mL respectively for 1% CHG in comparison to the 1% CHG concentration for P. aeruginosa (2,500 CFU/mL) and E. coli (22,334.3 CFU/mL). Additionally. P. aeruginosa and E. coli had no colonies in any of the trials at 7% and 9% CHG, while C. albicans and S. aureus were present in numerous amounts. Conclusion Through numerous trials using an MBC as a new method, dose response curves for E. coli, P. aeruginosa, S. aureus, and C. albicans were deduced. The curves displayed how gram-positive microorganisms are more resistant to CHG than gram-negative microorganisms, defying what was previously assumed. In regards to various diseases and infections caused by these various bacteria, CHG may now be assesed for potential forms of treatment.

Long-Term Stability, Sterility, And Cost-Effectiveness of 0.05% Chlorhexidine Gluconate as Antisepsis for Intravitreal Injection.

Purpose: Commercially available chlorhexidine gluconate (CHG) has a beyond-use date of 24 h. This study evaluated the stability and sterility of 0.05% CHG for 30 days after opening and compared its cost to povidone iodine (PI) for intravitreal injection antisepsis. Methods: 0.05% CHG was aliquoted into 1-mL syringes and stored at room temperature or refrigerated. Turbidity, pH, high-performance liquid chromatography (HPLC), and sterility testing were performed. A cost analysis was conducted. Results: 0.05% CHG remained stable for at least 30 days. All samples had measured turbidity <0.5 nephelometric turbidity units. The pH of all samples remained between 5.0 and 7.0. HPLC demonstrated CHG concentration at day 30 relative to day 0 of 98.52% ± 4.16% at room temperature and 99.99% ± 3.38% at 2°C -6°C. The cost per week to perform 150 injections using 0.05% CHG was $463.25 when opening a new bottle daily compared with $16.73 for 5% PI. This cost decreased to $23.16 when utilizing a bottle of CHG for 30 days. Conclusion: 0.05% CHG remains stable and sterile for at least 30 days after opening. The ability to use CHG for at least 30 days after its opening significantly decreases its utilization expense.

The effects of chlorhexidine, povidone-iodine and vancomycin on growth and biofilms of pathogens that cause prosthetic joint infections: an in-vitro model

Chlorhexidine gluconate (CHG) and povidone-iodine (PI) are commonly used to prevent prosthetic joint infection (PJI) during total joint replacement; however, their effective concentrations and impact on biofilms are not well defined. To determine: (1) the in-vitro minimum inhibitory concentration of CHG and PI against model PJI-causing organisms and clinical isolates; (2) their impact on biofilm formation; (3) whether there is a synergistic benefit to combining the two solutions; and (4) whether adding the antibiotic vancomycin impacts antiseptic activity. We measured in-vitro growth and biofilm formation of Staphylococcus epidermidis, meticillin-sensitive and meticillin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, as well as recent clinical isolates, in the presence of increasing concentrations of CHG and/or PI.Checkerboard assays were used to measure potential synergy of the solutions together and with vancomycin. CHG and PI inhibited growth and biofilm formation of all model organisms tested at concentrations of 0.0004% and 0.33% or lower, respectively; highly dilute concentrations paradoxically increased biofilm formation. The solutions did notsynergize with one another and acted independently of vancomycin. CHG and PI are effective at lower concentrations than typically used, establishing baselines to support further clinical trials aimed at optimizing wound disinfection. There is no synergistic advantage to using both in combination. Vancomycin is effective at inhibiting the growth of S.epidermidis and S.aureus; however, it stimulates P.aeruginosa biofilm production, suggesting in the rare case of P.aeruginosa PJI, it could exacerbate infection.

Relationship between chlorhexidine gluconate concentration and microbial colonization of patients' skin.

To characterize the relationship between chlorhexidine gluconate (CHG) skin concentration and skin microbial colonization. Serial cross-sectional study. Adult patients in medical intensive care units (ICUs) from 7 hospitals; from 1 hospital, additional patients colonized with carbapenemase-producing Enterobacterales (CPE) from both ICU and non-ICU settings. All hospitals performed routine CHG bathing in the ICU. Skin swab samples were collected from adjacent areas of the neck, axilla, and inguinal region for microbial culture and CHG skin concentration measurement using a semiquantitative colorimetric assay. We used linear mixed effects multilevel models to analyze the relationship between CHG concentration and microbial detection. We explored threshold effects using additional models. We collected samples from 736 of 759 (97%) eligible ICU patients and 68 patients colonized with CPE. On skin, gram-positive bacteria were cultured most frequently (93% of patients), followed by Candida species (26%) and gram-negative bacteria (20%). The adjusted odds of microbial recovery for every twofold increase in CHG skin concentration were 0.84 (95% CI, 0.80-0.87; P < .001) for gram-positive bacteria, 0.93 (95% CI, 0.89-0.98; P = .008) for Candida species, 0.96 (95% CI, 0.91-1.02; P = .17) for gram-negative bacteria, and 0.94 (95% CI, 0.84-1.06; P = .33) for CPE. A threshold CHG skin concentration for reduced microbial detection was not observed. On a cross-sectional basis, higher CHG skin concentrations were associated with less detection of gram-positive bacteria and Candida species on the skin, but not gram-negative bacteria, including CPE. For infection prevention, targeting higher CHG skin concentrations may improve control of certain pathogens.

Safety and efficacy of whole-body chlorhexidine gluconate cleansing with or without emollient in hospitalised neonates (NeoCHG): a multicentre, randomised, open-label, factorial pilot trial

Healthcare-associated infections account for substantial neonatal in-hospital mortality. Chlorhexidine gluconate (CHG) whole body skin application could reduce sepsis by lowering bacterial colonisation density, although safety and optimal application regimen is unclear. Emollients, including sunflower oil, may independently improve skin condition, thereby reducing sepsis. We aimed to inform which concentration and frequency of CHG, with or without emollient, would best balance safety and the surrogate marker of efficacy of reduction in bacterial colonisation, to be taken forward in a future pragmatic trial evaluating clinical outcomes of sepsis and mortality. In this multicentre, randomised, open-label, factorial pilot trial, neonates in two hospital sites (South Africa, Bangladesh) aged 1-6 days with gestational age ≥ 28 weeks and birthweight 1000-1999 g were randomly assigned in a factorial design stratified by site to three different concentrations of CHG (0.5%, 1%, and 2%), with or without emollient (sunflower oil) applied on working days vs alternate working days. A control arm received neither product. Caregivers were unblinded although laboratory staff were blinded to randomisation Co-primary outcomes were safety (change in neonatal skin condition score incorporating dryness, erythema, and skin breakdown) and efficacy in reducing bacterial colonisation density (change in total skin bacterial log10CFU from randomisation to day-3 and day-8). The trial is registered at the ISRCTN registry, ISRCTN69836999. Between Apr 12 2021 and Jan 18 2022, 208 infants were randomised and 198 were included in the final analysis. Skin condition scores were low with mean 0.1 (sd=0.3; N=208) at baseline, 0.1 (sd=0.3; N=199) at day 3 and 0.1 (sd=0.3; N=189) at day 8, with no evidence of differences between concentration (1% CHG vs 0.5% estimate=-0.3, 95% CI= (-1.2, 0.6), p=0.55. 2% CHG vs 0.5% CHG estimate=0.5 (-0.4, 1.4), p=0.30), increasing frequency (estimate=-0.4; 95% CI= (-1.1, 0.4), p=0.33), emollient (estimate=-0.5, (-1.2, 0.3), p=0.23) or with control (estimate=-0.9, (-2.3, 0.4), p=0.18). Mean log10CFU was 4.9 (sd=3.0; N=208) at baseline, 6.3 (sd=3.1; N=198) at day 3 and 8.4 (sd=2.6; N=183) with no evidence of differences between concentration (1% CHG vs 0.5% estimate=-0.4; 95% CI= (-1.1, 0.23); p=0.23. 2% CHG vs 0.5% CHG estimate=0.0 (-0.6, 0.6), p=0.96), with increasing frequency (estimate=-0.4; 95% CI= (-0.9, 0.2); p=0.17), with emollient (estimate=0.4, 95% CI= (-0.2, 0.9); p=0.18) or with control (estimate=-0.2, 95% CI= (-1.3, 0.9); p=0.73). By day-8, overall 158/183 (86%) of neonates were colonised with Enterobacterales, and 72/183 (39%) and 69/183 (9%) with Klebsiella spp resistant to third-generation cephalosporin and carbapenems, respectively. There were no CHG-related SAEs, emollient-related SAEs, grade 3 or 4 skin scores or grade 3 or 4 hypothermias. In this pilot trial of CHG with or without sunflower oil, no safety issues were identified, and further trials examining clinical outcomes are warranted. The relatively late start application of emollient, at a mean of 3.8 days of life, may have reduced the impact of the intervention although no subgroup effects were detected. There was no clear evidence in favour of a specific concentration of chlorhexidine, and there was rapid colonisation with Enterobacterales with frequent antimicrobial resistance, regardless of skin application regimen. The MRC Joint Applied Global Health award, the Global Antibiotic Research and Development Partnership (GARDP), MRC Clinical Trials Unit core funding (UKRI) and St. George's, University of London.

Augmented antiviral activity of chlorhexidine gluconate on herpes simplex virus type 1, H1N1 influenza A virus, and adenovirus in combination with salicylic acid.

The excessive usage of chlorhexidine gluconate (CHG) as a broad-spectrum antimicrobial reagent can have a negative impact on the environment and on human health. The aim of this study was to investigate the effectiveness of some plant-derived compounds in reducing the CHG concentration required to exert its antiviral activity. Antiviral assays were conducted according to EN 14476 (2019) against herpes simplex virus type 1 (HSV-1), H1N1 influenza A virus, and adenovirus type 5 (Ad-5) as enveloped and non-enveloped viral models to assess the synergistic interaction of CHG and natural additive compounds. The effective concentration of 0.247 mM CHG against HSV-1 was decreased tenfold in combination with 0.0125 mM salicylic acid, with a titer reduction of 1.47 ⋅ 104 CCID50/ml. The time required for complete inactivation of HSV-1 particles was reduced to 15 min when the virus was exposed to 0.061 mM CHG and 0.0125 mM salicylic acid. Additionally, the presence of salicylic acid protected the CHG activity against interfering substances. Our supplemented CHG formulation showed immediate antiviral effectiveness, which is important for management of the infections. CHG can be combined with salicylic acid to exhibit synergistic antiviral activity at lower concentrations and reduce the time required for inactivation. Furthermore, in the presence of interfering substances, the combination has higher antiviral activity than CHG alone.

Poster 152: Detrimental Effects of Chlorhexidine on Articular Cartilage Viability, Matrix, and Mechanics

Objectives: Chlorhexidine gluconate (CHG) is commonly used in antiseptic irrigation solutions for bacterial decontamination during orthopaedic surgery. Although the chondrotoxicity of CHG to articular cartilage has been reported, CHG irrigation is utilized by some surgeons to limit surgical site infection and to salvage grafts after accidental contamination during joint surgery. The full extent of CHG irrigation-related chondrotoxicity, as well as its effects on articular cartilage extracellular matrix and mechanical properties, are unknown. The purpose of this study was to determine the in vitro effects of a single one-minute CHG exposure on the viability, biochemical content, and mechanics of native articular cartilage explants. Methods: Articular cartilage explants (n=6 per group) were harvested from the femoral condyles of the porcine stifle and sectioned at the tidemark. Explants were bathed in Irrisept® chlorhexidine solution (0.05% CHG in sterile water) at varying concentrations (0% control, 0.01% CHG, and 0.05% CHG) to stimulate surgical irrigation for 1 minute, followed by complete phosphate-buffered saline wash and culture. After seven days of culture in chondrogenic medium, the explants were analyzed for viability (live/dead assay); collagen content (hydroxyproline assay); glycosaminoglycan (GAG) content (dimethyl methylene blue assay); and compressive mechanical testing (creep indentation testing). Statistical analyses were performed using a one-way ANOVA with post hoc Tukey test. Results: Seven days after CHG exposure, a dose-dependent decrease in mean chondrocyte viability was observed in the CHG groups (p&lt;0.001), with &lt;3% viability observed in the 0.05% CHG group (Figure 1). There was no significant difference in mean collagen content per wet weight among groups. Conversely, 0.05% CHG exposure led to a decrease in mean GAG per wet weight compared to negative control (p=0.029) and 0.01% CHG (p=0.046) (Figure 2). These changes in GAG content corresponded to observed changes in the compressive mechanical properties of the explants. A dose-dependent decrease in mean aggregate modulus and shear modulus was observed after CHG exposure (p&lt;0.029), indicating weakening of the cartilage matrix and increased deformation in response to compressive loads (Figure 3). Conclusions: One-minute CHG exposure to articular cartilage explants led to dose-dependent decreases in chondrocyte viability, GAG content, and compressive mechanical properties. These detrimental effects were observed for both 0.05% and 0.01% CHG concentrations. There is a paucity of literature examining the effects of CHG on articular cartilage matrix and mechanics, and the findings of this study suggest a lack of matrix maintenance following cell death, raising concern for risk of mechanical failure of the cartilage tissue. Clinicians should be judicious regarding the use of CHG irrigation at these concentrations in the presence of native articular cartilage.

Chlorhexidine susceptibility and Eagle effect in planktonic cells and biofilm of nosocomial isolates

The aim of this study is to evaluate the chlorhexidine gluconate (CHG) susceptibility in both planktonic cells and biofilm of 32 Gram-negative (Gn) and 6 Gram-positive (Gp) isolates by minimal inhibitory concentration (2-256μg/mL for Gn and 2-32μg/mL for Gp), minimal bactericidal concentration (4-256μg/mL for Gn and 2-32μg/mL for Gp) in planktonic cells, and minimal biofilm elimination concentration (128 ≥ 16,384μg/mL in Gn and 32 ≥ 16,384μg/mL in Gp) in biofilm environment. Our study showed that Gn isolates have higher minimal concentrations than Gp and bacteria in biofilms are more tolerant than planktonic ones. No correlation between MBC or MBEC and biofilm formation was statistically confirmed. The Eagle effect, previously described for antimicrobials and antifungals, was evidenced in this work for CHG, an antiseptic. Besides that, the phenomenon was described in 23/38 isolates (60.5%), raising minimal concentration up to ≥ 16,384μg/mL. Our study showed that clinical isolates have a high ability to form biofilm allowing them to tolerate CHG concentrations as high as the ones used in clinical practice. Therefore, attention should be given to the occurrence of this phenomenon to avoid false susceptibility results.

Association of qacA/B and smr Carriage with Staphylococcus aureus Survival following Exposure to Antiseptics in an Ex Vivo Venous Catheter Disinfection Model.

Many health care centers have reported an association between Staphylococcus aureus isolates bearing efflux pump genes and an elevated MIC/minimal bactericidal concentration (MBC) to chlorhexidine gluconate (CHG) and other antiseptics. The significance of these organisms is uncertain, given that their MIC/MBC is typically far lower than the CHG concentration in most commercial preparations. We sought to evaluate the relationship between carriage of the efflux pump genes qacA/B and smr in S. aureus and the efficacy of CHG-based antisepsis in a venous catheter disinfection model. S. aureus isolates with and without smr and/or qacA/B were utilized. The CHG MICs were determined. Venous catheter hubs were inoculated and exposed to CHG, isopropanol, and CHG-isopropanol combinations. The microbiocidal effect was calculated as the percent reduction in CFU following exposure to the antiseptic relative to the control. The qacA/B- and smr-positive isolates had modest elevations in the CHG MIC90 compared to the qacA/B- and smr-negative isolates (0.125 mcg/ml vs. 0.06 mcg/ml, respectively). However, the CHG microbiocidal effect was significantly lower for qacA/B- and/or smr-positive strains than for susceptible isolates, even when the isolates were exposed to CHG concentrations up to 400 μg/mL (0.04%); this finding was most notable for isolates bearing both qacA/B and smr (89.3% versus 99.9% for the qacA/B- and smr-negative isolates; P = 0.04). Reductions in the median microbiocidal effect were also observed when these qacA/B- and smr-positive isolates were exposed to a solution of 400 μg/mL (0.04%) CHG and 70% isopropanol (89.5% versus 100% for the qacA/B- and smr-negative isolates; P = 0.002). qacA/B- and smr-positive S. aureus isolates have a survival advantage in the presence of CHG concentrations exceeding the MIC. These data suggest that traditional MIC/MBC testing may underestimate the ability of these organisms to resist the effects of CHG. IMPORTANCE Antiseptic agents, including chlorhexidine gluconate (CHG), are commonly utilized in the health care environment to reduce rates of health care-associated infections. A number of efflux pump genes, including smr and qacA/B, have been reported in Staphylococcus aureus isolates that are associated with higher MICs and minimum bactericidal concentrations (MBCs) to CHG. Several health care centers have reported an increase in the prevalence of these S. aureus strains following an escalation of CHG use in the hospital environment. The clinical significance of these organisms, however, is uncertain, given that the CHG MIC/MBC is far below the concentration in commercial preparations. We present the results of a novel surface disinfection assay utilizing venous catheter hubs. We found that qacA/B-positive and smr-positive S. aureus isolates resist killing by CHG at concentrations far exceeding the MIC/MBC in our model. These findings highlight that traditional MIC/MBC testing is insufficient to evaluate susceptibility to antimicrobials acting on medical devices.

The Investigation of the Efficacy of Some Antiseptics and Disinfectants to Vancomycin-Resistant Enterococci

Disinfection of contaminated material, surface and body parts with appropriate substances is one of the most effective practices in preventing the infection-colonization of Vancomycin-Resistant Enterococci (VRE). In this study, 1/10 and 1/100 dilutions of 5% sodium hypochlorite, 4% concentration of chlorhexidine gluconate and 0.1% and 0.5% concentrations of Akacid plus’s efficacy against VRE strains at 1, 5, 15 and 30 minutes was tested. Sixty-nine vancomycin-resistant E. faecium strains isolated from different body samples between 2012 and 2014 were included in the study. The BD Phoenix 100® fully automated system was used for the identification of strains and detection of vancomycin resistance. Quantitative Suspension Test method EN 1276 (March 2010) was used to evaluate the bactericidal activities of chemical disinfectants and antiseptics used in European Union countries in the investigation of disinfectant susceptibility of VRE strains. Five log10 decrease (105) in the number of bacteria in the initial test suspension between the number of bacteria after using the disinfectant indicates that the disinfectant is effective. In this study, it has been determined that a 1/10 dilution of 5% sodium hypochlorite (bleach) is the most effective disinfectant on VREs in all minutes and conditions. Effectiveness of 1/100 dilution of bleach has a significant decrease in dirty conditions. Akacid plus was not effective on all strains in any contact times we tested. It has been observed that Akacid plus is the disinfectant least affected by the changes in environmental conditions in all minutes. Chlorhexidine gluconate (4%) was ineffective in clean and dirty conditions in just 1 minute, while from the 5th minute, its effectiveness was found to be statistically at the same level as the 1/10 dilution of bleach. There was no decrease in the activities of chlorhexidine due to the changing environmental conditions. In conclusion, it has been determined that a 1/10 dilution of 5% sodium hypochlorite (bleach) is the most effective disinfectant on VREs in all minutes and conditions, but dirty environmental conditions cause a significant decrease in the effectiveness of sodium hypochlorite. In addition, it was observed that the effectiveness of all disinfectants and antiseptics on VREs increased as the contact time with the substances increased.

Myelin toxicity of chlorhexidine in zebrafish larvae.

Chlorhexidine gluconate (CHG) is a topical antiseptic solution recommended for skin preparation before central venous catheter placement and maintenance in adults and children. Although CHG is not recommended for use in children aged <2 months owing to limited safety data, it is commonly used in neonatal intensive care units worldwide. We used zebrafish model to verify the effects of early-life exposure to CHG on the developing nervous system, highlighting its impact on oligodendrocyte development and myelination. Zebrafish embryos were exposed to different concentrations of CHG from 4 h post fertilization to examine developmental toxicity. The hatching rate, mortality, and malformation of the embryos/larvae were monitored. Oligodendrocyte lineage in transgenic zebrafish embryos was used to investigate defects in oligodendrocytes and myelin. Myelin structure, locomotor behavior, and expression levels of genes involved in myelination were investigated. Exposure to CHG significantly induced oligodendrocyte defects in the central nervous system, delayed myelination, and locomotor alterations. Ultra-microstructural changes with splitting and fluid-accumulated vacuoles between the myelin sheaths were found. Embryonic exposure to CHG decreased myelination, in association with downregulated mbpa, plp1b, and scrt2 gene expression. Our results suggest that CHG has a potential for myelin toxicity in the developing brain. To date, the neurodevelopmental toxicity of chlorhexidine gluconate (CHG) exposure on the developing brains of infants remains unknown. We demonstrated that CHG exposure to zebrafish larvae resulted in significant defects in oligodendrocytes and myelin sheaths. These CHG-exposed zebrafish larvae exhibited structural changes and locomotor alterations. Given the increased CHG use in neonates, this study is the first to identify the risk of early-life CHG exposure on the developing nervous system.

Anti-oomycete Activity of Chlorhexidine Gluconate: Molecular Docking and in vitro Studies.

Saprolegniosis is one of the most catastrophic oomycete diseases of freshwater fish caused by the members of the genus Saprolegnia. The disease is responsible for huge economic losses in the aquaculture industry worldwide. Until 2002, Saprolegnia infections were effectively controlled by using malachite green. However, the drug has been banned for use in aquaculture due to its harmful effect. Therefore, it has become important to find an alternate and safe anti-oomycete agent that is effective against Saprolegnia. In this study, we investigated the anti-oomycete activity of chlorhexidine gluconate (CHG) against Saprolegnia. Before in vitro evaluation, molecular docking was carried out to explore the binding of CHG with vital proteins of Saprolegnia, such as S. parasitica host-targeting protein 1 (SpHtp1), plasma membrane ATPase, and TKL protein kinase. In silico studies revealed that CHG binds with these proteins via hydrogen bonds and hydrophobic interactions. In an in vitro study, the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of CHG against S. parasitica were found to be 50 mg/L. Further, it was tested against S. australis, another species of Saprolegnia, and the MIC and MFC were found to be 100 and 200 mg/L, respectively. At 500 mg/L of CHG, there was complete inhibition of the radial growth of Saprolegnia hyphae. In propidium iodide (PI) uptake assay, CHG treated hyphae had bright red fluorescence of PI indicating the disruption of the cell membrane. The results of the present study indicated that CHG could effectively inhibit Saprolegnia and hence can be used for controlling Saprolegniasis in cultured fish.

Evaluation of Chlorhexidine Concentration on the Skin After Preoperative Surgical Site Preparation in Breast Surgery-A Randomized Controlled Trial.

Although there is a rationale supporting that preoperative showering with 2% or 4% chlorhexidine gluconate (CHG) would decrease skin bacterial colonization, there is no consensus that this practice reduces the risk of surgical site infection (SSI). Analyze the skin concentration of CHG after preoperative showering associated with the traditional skin preparation with CHG 4% for breast surgery. Randomized controlled trial that included 45 patients, all candidates for augmentation mammaplasty, allocated into three groups (A: no preoperative showering; B: one preoperative showering; C: two preoperative showering with CHG 4%) in a 1:1:1 ratio. Skin swabs collection was performed right before the surgical incision. The samples were, then, sent to spectrophotometry in order to determine the skin concentration of CHG at the beginning of surgery. The age ranged from 18 to 61 years, with a mean of 37 years old. Group C had the lowest median concentration (0.057) followed by group B (0.060) and group A (0.072), however, with no statistical significance. The areola was the place with the lowest median concentration level (0.045), followed by the axilla (0.061) and the inframammary fold (IMF) (0.069). Still, when comparing the distribution of the sites, a statistically significant difference was found only between the axilla and the areola (p = 0.022). Preoperative showering with CHG 4% did not increase the concentration of this agent on the skin surface right before the surgical incision. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Phenotypic and genotypic changes of Staphylococcus aureus in the presence of the inappropriate concentration of chlorhexidine gluconate

BackgroundChlorhexidine gluconate (CHG) is a disinfectant agent with different applications in health care. Improper use of CHG causes antimicrobial resistance in bacteria as a public health threat. Since Staphylococcus aureus is a common bacteria, it is expected usually exposed to CHG in the hospital and community. The present study aimed to correlate the phenotypic and genotypic changes in a S. aureus strain upon serial adaptation with supra-inhibitory CHG concentration for 50 days.ResultsAfter in vitro serial culture of 5 × 105 CFU/ml of a clinical vancomycin-susceptible S. aureus strain (VAN-S) into brain heart infusion (BHI) broth containing CHG 1/4, 1/2, 1, and 2 × minimal inhibitory concentration (MIC) values of VAN-S in 37 °C during 50 days, we isolated a S. aureus strain (CHGVan-I) with a ≥ twofold decrease in susceptibility to CHG and vancomycin. CHG-induced CHGVan-I strain was considered as a vancomycin-intermediate S. aureus (VISA) strain with a VAN MIC of 4 μg/ml using the broth macro dilution method. However, reduced resistance was observed to tetracycline family antibiotics (doxycycline and tetracycline) using a modified Kirby-Bauer disk diffusion test. Moreover, a remarkable reduction was detected in growth rate, hemolysis activity (the lysis of human red blood cells by alpha-hemolysin), and colony pigmentation (on BHI agar plates). Biofilm formation (using the Microtiter plate method and crystal violet staining) was significantly increased upon CHG treatment. Adaptive changes in the expression of a set of common genes related to the development of VISA phenotype (graTSR, vraTSR, walKR, agr RNAIII, sceD, pbpB, and fmtA) were analyzed by Reverse Transcription quantitative PCR (RT-qPCR) experiment. Significant changes in vraTSR, agr RNAIII, sceD, and pbpB expression were observed. However, gene sequencing of the two-component system vraTSR using the Sanger sequencing method did not detect any non-synonymous substitution in CHGVan-I compared to wild-type. The clonality of VAN-S and CHGVan-I strains was verified using the pulsed-field gel electrophoresis (PFGE) method.ConclusionsThe importance of the present study should be stated in new detected mechanisms underlying VISA development. We found a link between the improper CHX use and the development of phenotypic and genotypic features, typical of VISA clinical isolates, in a CHG-induced strain.Since disruption of the cell wall biosynthesis occurs in VISA isolates, our CHG-induced VISA strain proved new insights into the role of CHG in the stimulation of the S. aureus cell wall.

Comparison of Skin Antisepsis between Povidone-Iodine and Olanexidine Gluconate in Hepato-Biliary-Pancreatic Surgery

Introduction: Surgical site infections (SSIs) are major postoperative complications following hepato-biliary-pancreatic surgery. Globally, to reduce SSIs, especially superficial SSIs (S-SSIs), 4-5% chlorhexidine gluconate (CHG) is used for preoperative skin antisepsis. However, in Japan, since only a CHG concentration of less than 1% is permitted, Povidone-iodine (PVI) is commonly used. Recently, Olanexidine Gluconate (OLG) was developed as an alternative for CHG. We compared the cost and efficacy of preoperative skin cleansing with OLG compared to PVI in preventing S-SSI. Methods: We investigated patients who underwent laparotomy for hepatectomy or pancreatectomy between January 2019 and July 2021 at the Department of Hepato-Biliary-Pancreatic Surgery, Ehime University, excluding emergency surgery cases. PVI was used in all cases from January 2019 to December 2020 (PVI-group), while OLG was used in all cases from January 2021. We surveyed the presence of S-SSI based on CDC guidelines. We also evaluated patient demographic data, anthropometric parameters and perioperative data. Result: The PVI and OLG groups included 144 and 35 patients, respectively. The incidence of S-SSI was 3.5% (5 patients) in the PVI group and 2.9% (1 patient) in the OLG group, indicating no statistically significant difference. Three patients in the PVI group had adverse events, with none in the OLG group. Further, the cost of PVI was significantly lower than that of OLG. Conclusion: OLG did not show significant reduction of S-SSIs, although our study is limited by the small sample size. Therefore, antisepsis with PVI is useful considering its current widespread use and medical costs in Japan.

1. The Relationship Between Chlorhexidine Skin Concentration and Multidrug-Resistant Organism (MDRO) Colonization in ICU Patients

BackgroundDaily bathing of ICU patients with chlorhexidine gluconate (CHG) is an important method for healthcare-associated infection prevention. We set out to understand the relationship between CHG concentrations and MDRO colonizationMethodsIn our trauma/surgical ICU at a large urban medical center, we performed CHG concentrations 2 days/week at 4 times points relative to CHG bathing (Medline, Northfiled, IL) application: 30 min. prior, and 30 min., 6 hrs., and 12 hrs. after application. CHG testing was done at 4 body sites: lateral neck, anterior chest, arm, and inguinal fold. On the contralateral side we tested the presence of the following 4 MDROs: methicillin resistant S. aureus (MRSA), and 3 enteric bacteria--extended spectrum beta-lactamase (ESBL)+ gram-negative rods, vancomycin resistant enterococcus (VRE), and carbapenem resistant enterobacteriaceae (CRE).ResultsWe performed testing for 256 patient-days total, of which 42 were swabbed 1 time, 38 swabbed twice, 79 swabbed 3 times, and 97 swabbed 4 times (patient movement for tests, ICU transfer were limitations). Mean CHG skin concentrations were above the MICs of pathogens at all post-CHG application time points at all body sites at all times points (Figure) and decreased during the time points after bathing. In a logistic regression model controlling for patient characteristics, MRSA detection was inversely associated with CHG concentration with an 18% increase in odds of recovery for each 2-fold decrease in CHG concentration, as well as presence of a GI device and lack of ability to sit and roll. In a logistic regression model controlling for patient characteristics, resistant enteric bacteria detection was inversely associated with CHG concentration with an 11% increase in odds of recovery for each 2-fold decrease in CHG concentration, as well as mechanical ventilation, GI device, central line, and ICU duration. ConclusionIn our large study of CHG use and its association with MDRO detection, CHG concentrations decreased during the 24 hours after application, but were typically above concentrations considered adequate to kill MDROs. CHG concentration were inversely associated with the presence of MRSA and resistant enterics, suggesting that CHG application quality is a key component of the CHG bathing process.Disclosures Loren G. Miller, MD, MPH, Medline (Grant/Research Support, Other Financial or Material Support, Contributed product) Stryker (Other Financial or Material Support, Contributed product) Xttrium (Other Financial or Material Support, Contributed product) James A. McKinnell, MD, Medline (Grant/Research Support)

Integrated genomic, epidemiologic investigation of Candida auris skin colonization in a skilled nursing facility.

Candida auris is a fungal pathogen of high concern due to its ability to cause healthcare-associated infections and outbreaks, its resistance to antimicrobials and disinfectants and its persistence on human skin and in the inanimate environment. To inform surveillance and future mitigation strategies, we defined the extent of skin colonization and explored the microbiome associated with C. auris colonization. We collected swab specimens and clinical data at three times points between January and April 2019 from 57 residents (up to ten body sites each) of a ventilator-capable skilled nursing facility with endemic C. auris and routine chlorhexidine gluconate (CHG) bathing. Integrating microbial-genomic and epidemiologic data revealed occult C. auris colonization of multiple body sites not targeted commonly for screening. High concentrations of CHG were associated with suppression of C. auris growth but not with deleterious perturbation of commensal microbes. Modeling human mycobiome dynamics provided insight into underlying alterations to the skin fungal community as a possible modifiable risk factor for acquisition and persistence of C. auris. Failure to detect the extensive, disparate niches of C. auris colonization may reduce the effectiveness of infection-prevention measures that target colonized residents, highlighting the importance of universal strategies to reduce C. auris transmission.

Chlorhexidine Wipes to Reduce Multidrug-Resistant Gram-negative Bacterial Colonization and Healthcare-associated Infections among Medical Inpatients: A Cluster-Randomized Trial

Objective: To evaluate efficacy of chlorhexidine gluconate (CHG) to decolonize multidrug-resistant (MDR) gram-negative bacilli (GNB) bacteria, and to reduce healthcare associated infections (HAIs) in general medical inpatients. Materials and Methods: A 1-year, cluster-randomized study was conducted in a university hospital-based general medical unit. Eligible patients were randomized by study ward for routine daily and extra wiping with non-rinsed CHG-cloths (CHG group, n=145) or rinsed, non-medicated soap bath (control group, n=145), consecutively to the end of study. Study nurses received training and audits per CHG protocol. In all participants, axillae, groins, and perianal area were sampled to detect GNB colonization, on day 4 to 7 and day 11 to 14 of admission, by surveillance culture. All were followed for incidence rates of HAIs to day 14 of the study, or study exclusion. Results: MDR GNB colonization were significantly lower in CHG group than those of control group, both day 4 to 7 (15.9% versus 43.4%, respectively, p&lt;0.01), and day 11 to 14 of admission (20.6% versus 65.4%, respectively, p&lt;0.01). The incidence rates of overall HAIs did not differ between groups (5.80 versus 7.10 episodes per 1,000 patient-day, respectively, p=0.84). Three patients developed minor skin irritation in CHG group. Discussion: To the investigators’ knowledge, the present study is the first to demonstrate significant CHG reduction of MDR GNB colonization among medical patients in non-critical care unit. Use of non-rinsed CHG bath, personnel training, and audits, may maintain adequate skin concentration of CHG, and lower risk of cross-transmission. To effectively reduce HAIs, combined CHG bath and bundle of care may be required. Conclusion: Non-rinsed chlorhexidine baths are safe, well-tolerated, and effective to reduce MDR gram-negative bacterial colonization among general medical inpatients, and possible to lower risk of subsequent HAIs and cross-transmission, by day 14 of admission. Keywords: Multidrug-resistant gram-negative bacilli, Chlorhexidine bath, Decolonization, Healthcare associated infections, General medical inpatients

Implementing daily chlorhexidine gluconate (CHG) bathing in VA settings: The human factors engineering to prevent resistant organisms (HERO) project

Daily use of chlorhexidine gluconate (CHG) has been shown to reduce risk of healthcare-associated infections. We aimed to assess moving CHG bathing into routine practice using a human factors approach. We evaluated implementation in non-intensive care unit (ICU) settings in the Veterans Health Administration. Our multiple case study approach included non-ICU units from 4 Veterans Health Administration settings. Guided by the Systems Engineering Initiative for Patient Safety, we conducted focus groups and interviews to capture barriers and facilitators to daily CHG bathing. We measured compliance using observations and skin CHG concentrations. Barriers to daily CHG include time, concern of increasing antibiotic resistance, workflow and product concerns. Facilitators include engagement of champions and unit shared responsibility. We found shortfalls in patient education, hand hygiene and CHG use on tubes and drains. CHG skin concentration levels were highest among patients from spinal cord injury units. These units applied antiseptic using 2% CHG impregnated wipes vs 4% CHG solution/soap. Non-ICUs implementing CHG bathing must consider human factors and work system barriers to ensure uptake and sustained practice change. Well-planned rollouts and a unit culture promoting shared responsibility are key to compliance with daily CHG bathing. Successful implementation requires attention to staff education and measurement of compliance.

Impact of preoperative chlorhexidine gluconate (CHG) application methods on preoperative CHG skin concentration.

Elective surgical patients routinely bathe with chlorhexidine gluconate (CHG) at home days prior to their procedures. However, the impact of home CHG bathing on surgical site CHG concentration is unclear. We examined 3 different methods of applying CHG and hypothesized that different application methods would impact resulting CHG skin concentration.