Tom Elliott

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.

Antimicrobial efficacy of copper surfaces against spores and vegetative cells of Clostridium difficile: the germination theory

OBJECTIVESnPersistent contamination of surfaces by spores of Clostridium difficile is a major factor influencing the spread of C. difficile-associated diarrhoea (CDAD) in the clinical setting. In recent years, the antimicrobial efficacy of metal surfaces has been investigated against microorganisms including methicillin-resistant Staphylococcus aureus. This study compared the survival of C. difficile on stainless steel, a metal contact surface widely used in hospitals, and copper surfaces.nnnMETHODSnAntimicrobial efficacy was assessed using a carrier test method against dormant spores, germinating spores and vegetative cells of C. difficile (NCTC 11204 and ribotype 027) over a 3 h period in the presence and absence of organic matter.nnnRESULTSnCopper metal eliminated all vegetative cells of C. difficile within 30 min, compared with stainless steel which demonstrated no antimicrobial activity (P < 0.05). Copper significantly reduced the viability of spores of C. difficile exposed to the germinant (sodium taurocholate) in aerobic conditions within 60 min (P < 0.05) while achieving a >or=2.5 log reduction (99.8% reduction) at 3 h. Organic material did not reduce the antimicrobial efficacy of the copper surface (P > 0.05).nnnCONCLUSIONSnThe use of copper surfaces within the clinical environment and application of a germination solution in infection control procedures may offer a novel way forward in eliminating C. difficile from contaminated surfaces and reducing CDAD.

The Antimicrobial Efficacy of Copper Alloy Furnishing in the Clinical Environment: A Crossover Study

OBJECTIVEnTo determine whether copper incorporated into hospital ward furnishings and equipment can reduce their surface microbial load.nnnDESIGNnA crossover study.nnnSETTINGnAcute care medical ward with 19 beds at a large university hospital.nnnMETHODSnFourteen 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.nnnRESULTSnEight 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.nnnCONCLUSIONSnCopper 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.

Intravascular catheter-related sepsis – novel methods of prevention

Intravascular catheter-related sepsis continues to cause a significant degree of morbidity and mortality, and accounts for the majority of staphylococcal bacteraemias and septicaemias in hospitalised patients. Methods designed to prevent these infections include those directed at aseptic techniques involving the patient and improvements in catheter design. More recently catheters which are either coated or have incorporated into their polymers antimicrobial agents have been developed. The antimicrobial agents have included both antimicrobials which are used to treat infections as well as antiseptics. The antimicrobial catheters currently available appear to only give protection for relatively short periods of time (approximately 14 days). The use of these antimicrobial catheters needs to be restricted to the situation where infection rates and the risk to the patient of sepsis are relatively high. Further novel approaches for the prevention of these infections include the combination of low voltage electric current together with antimicrobials; these await clinical evaluation.

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.

Antimicrobial activity of a chlorhexidine intravascular catheter site gel dressing

OBJECTIVESnThe antimicrobial efficacy of a chlorhexidine gluconate (CHG) intravascular catheter gel dressing was evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and an extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Chlorhexidine deposition on the skin surface and release from the gel were determined.nnnMETHODSnThe antimicrobial efficacy was evaluated in in vitro studies following microbial inoculation of the dressing and application of the dressing on the inoculated surface of a silicone membrane and donor skin [with and without a catheter segment and/or 10% (v/v) serum] on diffusion cells. Antimicrobial activity was evaluated for up to 7 days. Chlorhexidine skin surface deposition and release were also determined.nnnRESULTSnMRSA and E. coli were not detectable within 5 min following direct inoculation onto the CHG gel dressing. On the silicone membrane, 3 log and 6 log inocula of MRSA were eradicated within 5 min and 1 h, respectively. Time to kill was prolonged in the presence of serum and a catheter segment. Following inoculation of donor skin with 6 log cfu of MRSA, none was detected after 24 h. Chlorhexidine was released from the gel after a lag time of 30 min and increasing amounts were detected on the donor skin surface over the 48 h test period. The CHG gel dressing retained its antimicrobial activity on the artificial skin for 7 days.nnnCONCLUSIONSnThe CHG intravascular catheter site gel dressing had detectable antimicrobial activity for up to 7 days, which should suppress bacterial growth on the skin at the catheter insertion site, thereby reducing the risk of infection.

Impact of catheter antimicrobial coating on species-specific risk of catheter colonization: a meta-analysis

BackgroundAntimicrobial catheters have been utilized to reduce risk of catheter colonization and infection. We aimed to determine if there is a greater than expected risk of microorganism-specific colonization associated with the use of antimicrobial central venous catheters (CVCs).MethodsWe performed a meta-analysis of 21 randomized, controlled trials comparing the incidence of specific bacterial and fungal species colonizing antimicrobial CVCs and standard CVCs in hospitalized patients.ResultsThe proportion of all colonized minocycline-rifampin CVCs found to harbor Candida species was greater than the proportion of all colonized standard CVCs found to have Candida. In comparison, the proportion of colonized chlorhexidine-silver sulfadiazine CVCs specifically colonized with Acinetobacter species or diphtheroids was less than the proportion of similarly colonized standard CVCs. No such differences were found with CVCs colonized with staphylococci.ConclusionCommercially-available antimicrobial CVCs in clinical use may become colonized with distinct microbial flora probably related to their antimicrobial spectrum of activity. Some of these antimicrobial CVCs may therefore have limited additional benefit or more obvious advantages compared to standard CVCs for specific microbial pathogens. The choice of an antimicrobial CVC may be influenced by a number of clinical factors, including a previous history of colonization or infection with Acinetobacter, diphtheroids, or Candida species.

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

BACKGROUNDnThe potential for microbial contamination of needleless intravascular (IV) connectors and the risk of subsequent infection are currently a subject of debate.nnnAIMnTo compare the number of micro-organisms associated with silver-coated and non-coated connectors in a clinical setting.nnnMETHODSnTwenty-five patients with haematological malignancies who required a central venous catheter (CVC) as part of their clinical management were studied. Each patients 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.nnnFINDINGSnThirty-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; Pxa0=xa00.49]. 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; Pxa0=xa00.001). In addition, the total number of micro-organisms present was less in the silver-coated connectors as compared to non-coated devices (Pxa0=xa00.001).nnnCONCLUSIONnThe 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.

Clinical evaluation of a chlorhexidine intravascular catheter gel dressing on short-term central venous catheters

BACKGROUNDnA major source of microbial colonization of short-term central venous catheters (CVC) is the patients endogenous skin microorganisms located at the CVC insertion site. The aim of this study was to determine if a transparent film dressing incorporating a 2% (weight/weight) chlorhexidine gluconate (CHG) gel decreases CVC and insertion site microbial colonization compared with a nonantimicrobial dressing in adult patients in critical care.nnnMETHODSnOn CVC removal, samples for microbiological investigation were taken from both the skin surrounding the CVC insertion site and also from sutures securing the CVC. The sutures and intradermal and tip sections of the CVC were also collected for microbiological investigation. Microorganisms recovered from the samples were subsequently tested for susceptibility to CHG.nnnRESULTSnThere was a significant reduction in the number of microorganisms recovered from the CVC insertion site, suture site, sutures, and catheter surface in the CHG dressing group (n = 136) compared with the nonantimicrobial dressing group (n = 137). There was no significant difference in susceptibility to CHG between the microorganisms isolated from the CHG and standard dressing study patients.nnnCONCLUSIONnA film dressing incorporating a CHG gel pad significantly reduced the number of microorganisms at the CVC insertion and suture sites with concomitant reduced catheter colonization.

A comparative study to evaluate surface microbial contamination associated with copper-containing and stainless steel pens used by nurses in the critical care unit

A clinical study was undertaken to compare the surface microbial contamination associated with pens constructed of either a copper alloy or stainless steel used by nurses on intensive care units. A significantly lower level of microbial contamination was found on the copper alloy pens.