Enhanced chlorhexidine skin penetration with 1,8-cineole.

BACKGROUND: Chlorhexidine (CHG) penetrates poorly into skin. The purpose of this study was to compare the depth of CHG skin permeation from solutions containing either 2% (w/v) CHG and 70% (v/v) isopropyl alcohol (IPA) or 2% (w/v) CHG, 70% (v/v) IPA and 2% (v/v) 1,8-cineole. METHODS: An ex-vivo study using Franz diffusion cells was carried out. Full thickness human skin was mounted onto the cells and a CHG solution, with or without 2% (v/v) 1,8-cineole was applied to the skin surface. After twenty-four hours the skin was sectioned horizontally in 100 µm slices to a depth of 2000 µm and the concentration of CHG in each section quantified using high performance liquid chromatography (HPLC). The data were analysed with repeated measures analysis of variance. RESULTS: The concentration of CHG in the skin on average was significantly higher (33.3% [95%, CI 1.5% - 74.9%]) when a CHG solution which contained 1,8-cineole was applied to the skin compared to a CHG solution which did not contain this terpene (P = 0.042). CONCLUSIONS: Enhanced delivery of CHG can be achieved in the presence of 1,8-cineole, which is the major component of eucalyptus oil. This may reduce the numbers of microorganisms located in the deeper layers of the skin which potentially could decrease the risk of surgical site infection.

Microbiologic contamination of a positive- and a neutral- displacement needleless intravenous access device in clinical use.

The use of a positive-displacement needleless intravenous access device was associated with lower microbial contamination rates compared with a neutral-displacement device when used on central venous catheters in hemato-oncology patients. In addition, rates of central line-associated bloodstream infection did not differ when either device was used.

Antimicrobial activity and skin permeation of iodine present in an iodine-impregnated surgical incise drape.

OBJECTIVES: The antimicrobial efficacy of an iodine-impregnated incise drape against MRSA was evaluated in a skin model. The permeation of iodine from this drape into the skin was also assessed. METHODS: The antimicrobial efficacy was evaluated in ex vivo studies following application of the surgical incise drape for various times on the surface of donor skin, which was inoculated with either 1 × 10(3) or 1 × 10(6) cfu MRSA/cm(2) skin and mounted on Franz diffusion cells. In some experiments the MRSA-inoculated skin was pre-incubated for 18 h at room temperature prior to applying the drape. Permeation of iodine into the skin using this model was also determined following application of the incise drape for 6 h. RESULTS: The iodine-impregnated drape demonstrated antimicrobial activity compared with the non-use of drape. This reached significance when a high inoculum of MRSA was applied with no pre-incubation period and when a low inoculum of MRSA was applied with a pre-incubation period (P = 0.002 and P = 0.014, respectively). Furthermore, in experiments wherein a high inoculum of MRSA was applied with no pre-incubation period, the iodine-impregnated drape demonstrated superior antimicrobial activity compared with the use of a non-antimicrobial drape (P < 0.001). MIC and MBC values of iodine were attained to 1500 µm below the skin surface. CONCLUSIONS: The iodine-impregnated surgical incise drape had detectable antimicrobial activity. Furthermore, iodine penetrated into the deeper layers of the skin. This property should suppress microbial regrowth at and around a surgical incision site, making its use preferable to the use of a standard drape or non-use of a drape.

Microbiological comparison of a silver-coated and a non-coated needleless intravascular connector in clinical use.

BACKGROUND: The potential for microbial contamination of needleless intravascular (IV) connectors and the risk of subsequent infection are currently a subject of debate. AIM: To compare the number of micro-organisms associated with silver-coated and non-coated connectors in a clinical setting. METHODS: Twenty-five patients with haematological malignancies who required a central venous catheter (CVC) as part of their clinical management were studied. Each patient's CVC was randomly designated to have attached either silver-coated or non-coated connectors. Before and after each manipulation of the connectors, the compression seals were decontaminated with a wipe incorporating 2% (w/v) chlorhexidine gluconate in 70% (v/v) isopropyl alcohol. Following four days in situ, the number of micro-organisms recovered from 119 silver-coated and 117 non-coated connectors was determined. FINDINGS: Thirty-six (30.3%) silver-coated connectors had micro-organisms present on the external silicone compression seal compared to 41 (35%) non-coated connectors [odds ratio (OR): 0.8; 95% confidence interval (CI): 0.47-1.39; P = 0.49]. Conversely, the internal fluid pathway of 31 (26.1%) silver-coated connectors had micro-organisms present compared to 55 (47.0%) of the non-coated connectors (OR: 0.40; 95% CI: 0.23-0.69; P = 0.001). In addition, the total number of micro-organisms present was less in the silver-coated connectors as compared to non-coated devices (P = 0.001). CONCLUSION: The use of a silver-coated connector with a dedicated decontamination regime may reduce the risk of catheter-related bloodstream infection acquired via the intraluminal route.

The antimicrobial efficacy of copper alloy furnishing in the clinical environment: a crossover study.

OBJECTIVE: To determine whether copper incorporated into hospital ward furnishings and equipment can reduce their surface microbial load. DESIGN: A crossover study. SETTING: Acute care medical ward with 19 beds at a large university hospital. METHODS: Fourteen types of frequent-touch items made of copper alloy were installed in various locations on an acute care medical ward. These included door handles and push plates, toilet seats and flush handles, grab rails, light switches and pull cord toggles, sockets, overbed tables, dressing trolleys, commodes, taps, and sink fittings. Their surfaces and those of equivalent standard items on the same ward were sampled once weekly for 24 weeks. The copper and standard items were switched over after 12 weeks of sampling to reduce bias in usage patterns. The total aerobic microbial counts and the presence of indicator microorganisms were determined. RESULTS: Eight of the 14 copper item types had microbial counts on their surfaces that were significantly lower than counts on standard materials. The other 6 copper item types had reduced microbial numbers on their surfaces, compared with microbial counts on standard items, but the reduction did not reach statistical significance. Indicator microorganisms were recovered from both types of surfaces; however, significantly fewer copper surfaces were contaminated with vancomycin-resistant enterococci, methicillin-susceptible Staphylococcus aureus, and coliforms, compared with standard surfaces. CONCLUSIONS: Copper alloys (greater than or equal to 58% copper), when incorporated into various hospital furnishings and fittings, reduce the surface microorganisms. The use of copper in combination with optimal infection-prevention strategies may therefore further reduce the risk that patients will acquire infection in healthcare environments.

Role of copper in reducing hospital environment contamination.

The environment may act as a reservoir for pathogens that cause healthcare-associated infections (HCAIs). Approaches to reducing environmental microbial contamination in addition to cleaning are thus worthy of consideration. Copper is well recognised as having antimicrobial activity but this property has not been applied to the clinical setting. We explored its use in a novel cross-over study on an acute medical ward. A toilet seat, set of tap handles and a ward entrance door push plate each containing copper were sampled for the presence of micro-organisms and compared to equivalent standard, non-copper-containing items on the same ward. Items were sampled once weekly for 10 weeks at 07:00 and 17:00. After five weeks, the copper-containing and non-copper-containing items were interchanged. The total aerobic microbial counts per cm(2) including the presence of 'indicator micro-organisms' were determined. Median numbers of microorganisms harboured by the copper-containing items were between 90% and 100% lower than their control equivalents at both 07:00 and 17:00. This reached statistical significance for each item with one exception. Based on the median total aerobic cfu counts from the study period, five out of ten control sample points and zero out of ten copper points failed proposed benchmark values of a total aerobic count of <5cfu/cm(2). All indicator micro-organisms were only isolated from control items with the exception of one item during one week. The use of copper-containing materials for surfaces in the hospital environment may therefore be a valuable adjunct for the prevention of HCAIs and requires further evaluation.

Penetration of chlorhexidine into human skin.

This study evaluated a model of skin permeation to determine the depth of delivery of chlorhexidine into full-thickness excised human skin following topical application of 2% (wt/vol) aqueous chlorhexidine digluconate. Skin permeation studies were performed on full-thickness human skin using Franz diffusion cells with exposure to chlorhexidine for 2 min, 30 min, and 24 h. The concentration of chlorhexidine extracted from skin sections was determined to a depth of 1,500 microm following serial sectioning of the skin using a microtome and analysis by high-performance liquid chromatography. Poor penetration of chlorhexidine into skin following 2-min and 30-min exposures to chlorhexidine was observed (0.157 +/- 0.047 and 0.077 +/- 0.015 microg/mg tissue within the top 100 microm), and levels of chlorhexidine were minimal at deeper skin depths (less than 0.002 microg/mg tissue below 300 microm). After 24 h of exposure, there was more chlorhexidine within the upper 100-microm sections (7.88 +/- 1.37 microg/mg tissue); however, the levels remained low (less than 1 microg/mg tissue) at depths below 300 microm. There was no detectable penetration through the full-thickness skin. The model presented in this study can be used to assess the permeation of antiseptic agents through various layers of skin in vitro. Aqueous chlorhexidine demonstrated poor permeation into the deeper layers of the skin, which may restrict the efficacy of skin antisepsis with this agent. This study lays the foundation for further research in adopting alternative strategies for enhanced skin antisepsis in clinical practice.

Antimicrobial efficacy of chlorhexidine digluconate alone and in combination with eucalyptus oil, tea tree oil and thymol against planktonic and biofilm cultures of Staphylococcus epidermidis.

OBJECTIVES: Effective skin antisepsis and disinfection of medical devices are key factors in preventing many healthcare-acquired infections associated with skin microorganisms, particularly Staphylococcus epidermidis. The aim of this study was to investigate the antimicrobial efficacy of chlorhexidine digluconate (CHG), a widely used antiseptic in clinical practice, alone and in combination with tea tree oil (TTO), eucalyptus oil (EO) and thymol against planktonic and biofilm cultures of S. epidermidis. METHODS: Antimicrobial susceptibility assays against S. epidermidis in a suspension and in a biofilm mode of growth were performed with broth microdilution and ATP bioluminescence methods, respectively. Synergy of antimicrobial agents was evaluated with the chequerboard method. RESULTS: CHG exhibited antimicrobial activity against S. epidermidis in both suspension and biofilm (MIC 2-8 mg/L). Of the essential oils thymol exhibited the greatest antimicrobial efficacy (0.5-4 g/L) against S. epidermidis in suspension and biofilm followed by TTO (2-16 g/L) and EO (4-64 g/L). MICs of CHG and EO were reduced against S. epidermidis biofilm when in combination (MIC of 8 reduced to 0.25-1 mg/L and MIC of 32-64 reduced to 4 g/L for CHG and EO, respectively). Furthermore, the combination of EO with CHG demonstrated synergistic activity against S. epidermidis biofilm with a fractional inhibitory concentration index of <0.5. CONCLUSIONS: The results from this study suggest that there may be a role for essential oils, in particular EO, for improved skin antisepsis when combined with CHG.