Antimicrobial activity of a chlorhexidine intravascular catheter site gel dressing

In Vitro Efficacy of Bacterial Cellulose Dressings Chemisorbed with Antiseptics against Biofilm Formed by Pathogens Isolated from Chronic Wounds

Local administration of antiseptics is required to prevent and fight against biofilm-based infections of chronic wounds. One of the methods used for delivering antiseptics to infected wounds is the application of dressings chemisorbed with antimicrobials. Dressings made of bacterial cellulose (BC) display several features, making them suitable for such a purpose. This work aimed to compare the activity of commonly used antiseptic molecules: octenidine, polyhexanide, povidone-iodine, chlorhexidine, ethacridine lactate, and hypochlorous solutions and to evaluate their usefulness as active substances of BC dressings against 48 bacterial strains (8 species) and 6 yeast strains (1 species). A silver dressing was applied as a control material of proven antimicrobial activity. The methodology applied included the assessment of minimal inhibitory concentrations (MIC) and minimal biofilm eradication concentration (MBEC), the modified disc-diffusion method, and the modified antibiofilm dressing activity measurement (A.D.A.M.) method. While in 96-well plate-based methods (MIC and MBEC assessment), the highest antimicrobial activity was recorded for chlorhexidine, in the modified disc-diffusion method and in the modified A.D.A.M test, povidone-iodine performed the best. In an in vitro setting simulating chronic wound conditions, BC dressings chemisorbed with polyhexanide, octenidine, or povidone-iodine displayed a similar or even higher antibiofilm activity than the control dressing containing silver molecules. If translated into clinical conditions, the obtained results suggest high applicability of BC dressings chemisorbed with antiseptics to eradicate biofilm from chronic wounds.

Effectiveness of chlorhexidine dressings to prevent catheter-related bloodstream infections. Does one size fit all? A systematic literature review and meta-analysis

Objective:

To evaluate the effectiveness of chlorhexidine (CHG) dressings to prevent catheter-related bloodstream infections (CRBSIs).

Design:

Systematic review and meta-analysis.

Methods:

We searched PubMed, CINAHL, EMBASE, and ClinicalTrials.gov for studies (randomized controlled and quasi-experimental trials) with the following criteria: patients with short- or long-term catheters; CHG dressings were used in the intervention group and nonantimicrobial dressings in the control group; CRBSI was an outcome. Random-effects models were used to obtain pooled risk ratios (pRRs). Heterogeneity was evaluated using the I2 test and the Cochran Q statistic.

Results:

In total, 20 studies (18 randomized controlled trials; 15,590 catheters) without evidence of publication bias and mainly performed in intensive care units (ICUs) were included. CHG dressings significantly reduced CRBSIs (pRR, 0.71; 95% CI, 0.58–0.87), independent of the CHG dressing type used. Benefits were limited to adults with short-term central venous catheters (CVCs), including onco-hematological patients. For long-term CVCs, CHG dressings decreased exit-site/tunnel infections (pRR, 0.37; 95% CI, 0.22–0.64). Contact dermatitis was associated with CHG dressing use (pRR, 5.16; 95% CI, 2.09–12.70); especially in neonates and pediatric populations in whom severe reactions occurred. Also, 2 studies evaluated and did not find CHG-acquired resistance.

Conclusions:

CHG dressings prevent CRBSIs in adults with short-term CVCs, including patients with an onco-hematological disease. CHG dressings might reduce exit-site and tunnel infections in long-term CVCs. In neonates and pediatric populations, proof of CHG dressing effectiveness is lacking and there is an increased risk of serious adverse events. Future studies should investigate CHG effectiveness in non-ICU settings and monitor for CHG resistance.

Chlorhexidine-impregnated sponge versus chlorhexidine gel dressing for short-term intravascular catheters: which one is better?

BACKGROUND

Chlorhexidine-gluconate (CHG) impregnated dressings may prevent catheter-related bloodstream infections (CRBSI). Chlorhexidine-impregnated sponge dressings (sponge-dress) and gel dressings (gel-dress) have never been directly compared. We used the data collected for two randomized-controlled trials to perform a comparison between sponge-dress and gel-dress.

METHODS

Adult critically ill patients who required short-term central venous or arterial catheter insertion were recruited. Our main analysis included only patients with CHG-impregnated dressings. The effect of gel-dress (versus sponge-dress) on major catheter-related infections (MCRI) and CRBSI was estimated using multivariate marginal Cox models. The comparative risks of dressing disruption and contact dermatitis were evaluated using logistic mix models for clustered data. An explanatory analysis compared gel-dress with standard dressings using either CHG skin disinfection or povidone iodine skin disinfection.

RESULTS

A total of 3483 patients and 7941 catheters were observed in 16 intensive care units. Sponge-dress and gel-dress were utilized for 1953 and 2108 catheters, respectively. After adjustment for confounders, gel-dress showed similar risk for MCRI compared to sponge-dress (HR 0.80, 95% CI 0.28-2.31, p = 0.68) and CRBSI (HR 1.13, 95% CI 0.34-3.70, p = 0.85), less dressing disruptions (OR 0.72, 95% CI 0.60-0.86, p < 0.001), and more contact dermatitis (OR 3.60, 95% CI 2.51-5.15, p < 0.01). However, gel-dress increased the risk of contact dermatitis only if CHG was used for skin antisepsis (OR 1.94, 95% CI 1.38-2.71, p < 0.01).

CONCLUSIONS

We described a similar infection risk for gel-dress and sponge-dress. Gel-dress showed fewer dressing disruptions. Concomitant use of CHG for skin disinfection and CHG-impregnated dressing may significantly increase contact dermatitis.

TRIALS REGISTRATION

These studies were registered within ClinicalTrials.gov (numbers NCT01189682 and NCT00417235 ).

Efficacy of chlorhexidine patches on central line-associated bloodstream infections in children

BACKGROUND

Central line-associated bloodstream infections (CLABSIs) are important hospital-acquired infections. Chlorhexidine-impregnated dressings (also known as chlorhexidine patches, CHG patches) are reported to decrease CLABSIs in adults. This study aims to determine the efficacy of CHG patches in reducing CLABSIs in children.

METHODS

An open-label randomized controlled trial was conducted in children aged 2 months to 18 years, requiring a short-term catheter. Patients were randomized into two groups, allocated to receive CHG patches or standard transparent dressings. Care of the catheter was in accordance with Asia Pacific Society of Infection Control (APSIC) recommendations. Central-line-associated bloodstream infections were defined using National Healthcare Safety Network surveillance criteria.

RESULTS

From April 2017 to April 2018, 192 children were enrolled. There were 108 CHG patch catheters and 101 standard dressing catheters, contributing to 3,113 catheter days. The median duration of catheter dwelling was 13 days, with an interquartile range (IQR) of 8-20 days. Half were placed at the jugular vein and 22% at the femoral vein. There were 23 CLABSI events. Incidence rates for CHG patches and standard dressings were 7.98 (95% confidence interval (CI), 4.25-13.65) and 6.74 (95% CI, 3.23-12.39) per 1,000 catheter days, respectively (incidence rate ratio 1.18; 95% CI, 0.52-2.70). The CLABSI pathogens were 15 Gram-negative bacteria, six Gram-positive bacteria, and two Candida organisms. Catheter colonization of CHG patches and standard dressings were 2.02 (95% CI, 0.42-5.91) and 3.07 (95% CI, 1.00-7.16) per 1,000 catheter days, respectively. Only local adverse effects occurred in 6.8% of the participants.

CONCLUSIONS

In our setting, there was no difference in CLABSI rates when the chlorhexidine patch dressings were compared with the standard transparent dressings. Strengthening of CLABSI prevention bundles is mandatory.

Effectiveness of a Chlorhexidine Dressing on Silver-coated External Ventricular Drain-associated Colonization and Infection: A Prospective Single-blinded Randomized Controlled Clinical Trial

Background

Observational studies have shown that dressings containing chlorhexidine gluconate (CHX) lower the incidence external ventricular drain (EVD)-associated infections (EVDAIs). This prospective, randomized controlled trial (RCT) studies the efficacy of CHX-containing dressings in reducing bacterial colonization.

Methods

In this RCT, patients aged ≥18 years undergoing emergency EVD placement were randomly given either a CHX-containing or an otherwise identical control dressing at the skin exit wound. The primary end-point was bacterial regrowth in cultured skin swab samples of the EVD exit wound. The secondary end-points were catheters processed by sonication, clinically diagnosed EVDAI and surgical treatment of hydrocephalus.

Results

From October 2013 to January 2016, a total of 57 patients were randomized to receive either a CHX or a control dressing (29 and 28 patients, respectively). Cutaneous bacterial regrowth at the EVD exit wound was significantly reduced over time (geometric mean ratio, 0.18; 95% confidence interval, .08-.42; P < .001). The incidence of colonized catheters was lower in the CHX group (5 of 28; 18%) than in the control group (10 of 27; 33%), with less microbial colonization on the subcutaneous portion. The infection rate was 4 of 28 (14%) in the CHX group, compared with 7 of 27 (26%) in the control group, with a substantially lower hydrocephalus treatment rate (7 of 28 [25%] vs 14 of 27 [52%], respectively).

Conclusion

Our data support the use of CHX dressings to reduce EVD exit site contamination, potentially reducing EVDAIs and permanent cerebrospinal fluid diversion procedures for hydrocephalus.

Clinical Trials Registration

NCT02078830.

Chlorhexidine-induced elastic and adhesive changes of Escherichia coli cells within a biofilm

Chlorhexidine is a widely used, commercially available cationic antiseptic. Although its mechanism of action on planktonic bacteria has been well explored, far fewer studies have examined its interaction with an established biofilm. The physical effects of chlorhexidine on a biofilm are particularly unknown. Here, the authors report the first observations of chlorhexidine-induced elastic and adhesive changes to single cells within a biofilm. The elastic changes are consistent with the proposed mechanism of action of chlorhexidine. Atomic force microscopy and force spectroscopy techniques were used to determine spring constants and adhesion energy of the individual bacteria within an Escherichia coli biofilm. Medically relevant concentrations of chlorhexidine were tested, and cells exposed to 1% (w/v) and 0.1% more than doubled in stiffness, while those exposed to 0.01% showed no change in elasticity. Adhesion to the biofilm also increased with exposure to 1% chlorhexidine, but not for the lower concentrations tested. Given the prevalence of chlorhexidine in clinical and commercial applications, these results have important ramifications on biofilm removal techniques.

Antimicrobial dressings for the prevention of catheter-related infections in newborn infants with central venous catheters

BACKGROUND

Central venous catheters (CVCs) provide secured venous access in neonates. Antimicrobial dressings applied over the CVC sites have been proposed to reduce catheter-related blood stream infection (CRBSI) by decreasing colonisation. However, there may be concerns on the local and systemic adverse effects of these dressings in neonates.

OBJECTIVES

We assessed the effectiveness and safety of antimicrobial (antiseptic or antibiotic) dressings in reducing CVC-related infections in newborn infants. Had there been relevant data, we would have evaluated the effects of antimicrobial dressings in different subgroups, including infants who received different types of CVCs, infants who required CVC for different durations, infants with CVCs with and without other antimicrobial modifications, and infants who received an antimicrobial dressing with and without a clearly defined co-intervention.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group (CNRG). We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2015, Issue 9), MEDLINE (PubMed), EMBASE (EBCHOST), CINAHL and references cited in our short-listed articles using keywords and MeSH headings, up to September 2015.

SELECTION CRITERIA

We included randomised controlled trials that compared an antimicrobial CVC dressing against no dressing or another dressing in newborn infants.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the CNRG. Two review authors independently assessed the eligibility and risk of bias of the retrieved records. We expressed our results using risk difference (RD) and risk ratio (RR) with 95% confidence intervals (CIs).

MAIN RESULTS

Out of 173 articles screened, three studies were included. There were two comparisons: chlorhexidine dressing following alcohol cleansing versus polyurethane dressing following povidone-iodine cleansing (one study); and silver-alginate patch versus control (two studies). A total of 855 infants from level III neonatal intensive care units (NICUs) were evaluated, 705 of whom were from a single study. All studies were at high risk of bias for blinding of care personnel or unclear risk of bias for blinding of outcome assessors. There was moderate-quality evidence for all major outcomes.The single study comparing chlorhexidine dressing/alcohol cleansing against polyurethane dressing/povidone-iodine cleansing showed no significant difference in the risk of CRBSI (RR 1.18, 95% CI 0.53 to 2.65; RD 0.01, 95% CI -0.02 to 0.03; 655 infants, moderate-quality evidence) and sepsis without a source (RR 1.06, 95% CI 0.75 to 1.52; RD 0.01, 95% CI -0.04 to 0.06; 705 infants, moderate-quality evidence). There was a significant reduction in the risk of catheter colonisation favouring chlorhexidine dressing/alcohol cleansing group (RR 0.62, 95% CI 0.45 to 0.86; RD -0.09, 95% CI -0.15 to -0.03; number needed to treat for an additional beneficial outcome (NNTB) 11, 95% CI 7 to 33; 655 infants, moderate-quality evidence). However, infants in the chlorhexidine dressing/alcohol cleansing group were significantly more likely to develop contact dermatitis, with 19 infants in the chlorhexidine dressing/alcohol cleansing group having developed contact dermatitis compared to none in the polyurethane dressing/povidone-iodine cleansing group (RR 43.06, 95% CI 2.61 to 710.44; RD 0.06, 95% CI 0.03 to 0.08; number needed to treat for an additional harmful outcome (NNTH) 17, 95% CI 13 to 33; 705 infants, moderate-quality evidence). The roles of chlorhexidine dressing in the outcomes reported were unclear, as the two assigned groups received different co-interventions in the form of different skin cleansing agents prior to catheter insertion and during each dressing change.In the other comparison, silver-alginate patch versus control, the data for CRBSI were analysed separately in two subgroups as the two included studies reported the outcome using different denominators: one using infants and another using catheters. There were no significant differences between infants who received silver-alginate patch against infants who received standard line dressing in CRBSI, whether expressed as the number of infants (RR 0.50, 95% CI 0.14 to 1.78; RD -0.12, 95% CI -0.33 to 0.09; 1 study, 50 participants, moderate-quality evidence) or as the number of catheters (RR 0.72, 95% CI 0.27 to 1.89; RD -0.05, 95% CI -0.20 to 0.10; 1 study, 118 participants, moderate-quality evidence). There was also no significant difference between the two groups in mortality (RR 0.55, 95% CI 0.15 to 2.05; RD -0.04, 95% CI -0.13 to 0.05; two studies, 150 infants, I² = 0%, moderate-quality evidence). No adverse skin reaction was recorded in either group.

AUTHORS' CONCLUSIONS

Based on moderate-quality evidence, chlorhexidine dressing/alcohol skin cleansing reduced catheter colonisation, but made no significant difference in major outcomes like sepsis and CRBSI compared to polyurethane dressing/povidone-iodine cleansing. Chlorhexidine dressing/alcohol cleansing posed a substantial risk of contact dermatitis in preterm infants, although it was unclear whether this was contributed mainly by the dressing material or the cleansing agent. While silver-alginate patch appeared safe, evidence is still insufficient for a recommendation in practice. Future research that evaluates antimicrobial dressing should ensure blinding of caregivers and outcome assessors and ensure that all participants receive the same co-interventions, such as the skin cleansing agent. Major outcomes like sepsis, CRBSI and mortality should be assessed in infants of different gestation and birth weight.

Antimicrobial Activity of a Novel Vascular Access Film Dressing Containing Chlorhexidine Gluconate

Background

Covering insertion sites with chlorhexidine impregnated dressings has been proven to be clinically effective in reducing catheter related blood stream infections (CR-BSI). Two chlorhexidine gluconate (CHG)-impregnated dressings are commercially available, a polyurethane foam disk and a film dressing containing a chlorhexidine gluconate-impregnated gel pad. While both have demonstrated efficacy in clinical settings, the major drawback of high cost and impaired IV insertion site visibility limits their usage. A new, simple film dressing containing CHG within its adhesive layer is now available. The objective of this study was to test the in vitro antimicrobial efficacy of the new dressing in comparison to the CHG-impregnated gel dressing.

Methods

Quantitative aliquots of suspensions (concentration of 1.0x10⁶ to 5.0x10⁶ cfu/sample) of clinically relevant challenge organisms (Staphylococcus species, gram-negative bacilli, Candida albicans) were incubated in contact with the new CHG-containing film dressing, a placebo version of the same (negative control) and the commercially available CHG-impregnated gel dressing (positive control). Serial dilutions of the surviving organisms were quantified using the pour plate after 1, 3, 5, and 7 days of incubation in order to calculate an antimicrobial log₁₀ reduction for each organism/dressing combination at each point in time.

Results

The new CHG-containing film dressing delivered greater than 5.0 log₁₀ reduction throughout the 7 days on all aerobic gram-negative bacilli and Staphylococcus species tested. As of day 1 the CHG-containing film dressing provided greater than 5.0 log₁₀ reduction on Candida albicans. There were no statistically significant differences in the log₁₀ reduction between the two dressings tested.

Conclusion

The new CHG-containing film dressing was found to be as effective as the chlorhexidine gluconate-impregnated gel dressing on clinically relevant microbes.

The Effect of Brief Exposure to Sub-Therapeutic Concentrations of Chlorhexidine Digluconate on the Susceptibility of Staphylococci to Platelet Microbicidal Protein

BACKGROUND

Antiseptic agents are widely used in hospitals and are essential when prevention and control of nosocomial infections is required. It is necessary to consider several aspects that affect the biocide activity because they have direct impact on the nosocomial infection rate. Organisms belonging to the Staphylococcus genus are involved in such infections and chlorhexidine digluconate (CHXD) is one of the most used antiseptic agents for human and animal health. In the context of such infections, anti-bacterial peptides have been isolated from platelets and have been termed platelet microbicidal proteins (PMP). Platelet microbicidal proteins have been shown to enhance the bacterial inhibitory activities of sub-therapeutic concentrations of antibiotics. The main objective of this study was to investigate the effect of brief exposure to different sub-therapeutic concentrations of CHXD on the susceptibility of staphylococci to PMP.

METHODS

The influence of brief exposure to three different sub-therapeutic concentrations of CHXD (0.005%, 0.0025%, and 0.00125%) on the subsequent staphylocidal effect of PMP was evaluated.

RESULTS

Among all clinical staphylococcal strains studied, all isolates were considered to be resistant to the bactericidal action of PMP. Exposure of staphylococci to CHXD prior to PMP resulted in significantly increased staphylococcal killing compared with the killing achieved with PMP alone. This enhanced effect was most marked for concentrations of CHXD of 0.005%.

CONCLUSION

The combined data indicate that PMP exerts cooperative bactericidal effect with CHXD. The anti-staphylococcal PMP and CHXD synergistic activity in vitro demonstrated in the present study make these molecules potentially useful for preventing endovascular catheter-associated infections. Future research based on animal and human models is needed to elucidate the in vivo efficacies and toxicities and utility in clinical practice.

No infection reduction using chlorhexidine wipes in total joint arthroplasty

BACKGROUND

Surgical site infection (SSI) after total joint arthroplasty (TJA) is a rare but devastating complication. Various skin antiseptic applications are used preoperatively to prevent SSI. Recent literature suggests 2% chlorhexidine gluconate (CHG) wipes reduce microbial content at surgical sites, but it is unclear whether they reduce rates of SSI.

QUESTIONS/PURPOSES

We compared the SSI rates between TJAs with and without CHG wipe use (1) with all TJAs in one group and (2) stratified by surgical subgroup (THA, TKA).

METHODS

We retrospectively reviewed all 3715 patients who underwent primary TJA from 2007 to 2009. CHG wipes were introduced at our facility on April 21, 2008. We compared SSI of patients before (n=1824) and after (n=1891) the introduction of CHG wipes. The wipes were applied 1 hour before surgery. There were 1660 patients with THA (845 CHG, 815 no CHG) and 2055 patients with TKA (1046 CHG, 1009 no CHG). Infections were diagnosed based on the Musculoskeletal Infection Society Guidelines for periprosthetic joint infection. All patients were tracked for 1 year.

RESULTS

SSI incidences were similar in patients receiving (1.0%, 18 of 1891) and not receiving (1.3%, 24 of 1824) CHG wipes. In patients with THA, there was no difference in SSI between those receiving (1.2%, 10 of 845) and not receiving (1.5%, 12 of 815) CHG wipes. In patients with TKA, there also was no difference in SSI between those receiving (0.8%, eight of 1046) and not receiving (1.2%, 12 of 1009) CHG wipes.

CONCLUSIONS

Introduction of CHG-impregnated wipes in the presurgical setting was not associated with a reduced SSI incidence. Our analysis suggests CHG wipes in TJA are unnecessary as an adjunct skin antiseptic, as suggested in previous smaller studies.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Randomized controlled trial of chlorhexidine dressing and highly adhesive dressing for preventing catheter-related infections in critically ill adults

RATIONALE

Most vascular catheter-related infections (CRIs) occur extraluminally in patients in the intensive care unit (ICU). Chlorhexidine-impregnated and strongly adherent dressings may decrease catheter colonization and CRI rates.

OBJECTIVES

To determine if chlorhexidine-impregnated and strongly adherent dressings decrease catheter colonization and CRI rates.

METHODS

In a 2:1:1 assessor-masked randomized trial in patients with vascular catheters inserted for an expected duration of 48 hours or more in 12 French ICUs, we compared chlorhexidine dressings, highly adhesive dressings, and standard dressings from May 2010 to July 2011. Coprimary endpoints were major CRI with or without catheter-related bloodstream infection (CR-BSI) with chlorhexidine versus nonchlorhexidine dressings and catheter colonization rate with highly adhesive nonchlorhexidine versus standard nonchlorhexidine dressings. Catheter-colonization, CR-BSIs, and skin reactions were secondary endpoints.

MEASUREMENTS AND MAIN RESULTS

A total of 1,879 patients (4,163 catheters and 34,339 catheter-days) were evaluated. With chlorhexidine dressings, the major-CRI rate was 67% lower (0.7 per 1,000 vs. 2.1 per 1,000 catheter-days; hazard ratio [HR], 0.328; 95% confidence interval [CI], 0.174-0.619; P = 0.0006) and the CR-BSI rate 60% lower (0.5 per 1,000 vs. 1.3 per 1,000 catheter-days; HR, 0.402; 95% CI, 0.186-0.868; P = 0.02) than with nonchlorhexidine dressings; decreases were noted in catheter colonization and skin colonization rates at catheter removal. The contact dermatitis rate was 1.1% with and 0.29% without chlorhexidine. Highly adhesive dressings decreased the detachment rate to 64.3% versus 71.9% (P < 0.0001) and the number of dressings per catheter to two (one to four) versus three (one to five) (P < 0.0001) but increased skin colonization (P < 0.0001) and catheter colonization (HR, 1.650; 95% CI, 1.21-2.26; P = 0.0016) without influencing CRI or CR-BSI rates.

CONCLUSIONS

A large randomized trial demonstrated that chlorhexidine-gel-impregnated dressings decreased the CRI rate in patients in the ICU with intravascular catheters. Highly adhesive dressings decreased dressing detachment but increased skin and catheter colonization. Clinical trial registered with www.clinicaltrials.gov (NCT 01189682).

Polymeric multilayers that localize the release of chlorhexidine from biologic wound dressings

Biologic wound dressings contain animal-derived components and are susceptible to high infection rates. To address this issue, we report an approach that permits incorporation of non-toxic levels of the small molecule antiseptic 'chlorhexidine' into biologic dressings. The approach relies on the fabrication of polyelectrolyte multilayer (PEMs) films containing poly(allylaminehydrochloride) (PAH), poly(acrylicacid) (PAA), and chlorhexidine acetate (CX) on elastomeric poly(dimethylsiloxane) (PDMS) sheets. The PEMs (20-100 nm thick) are subsequently stamped onto the wound-contact surface of a synthetic biologic dressing, Biobrane, which contains collagen peptides. Chlorhexidine loading in the PEMs was tailored by tuning the number of (CX/PAA) bilayers deposited, providing burst release of up to 0.98 ± 0.06 μg/cm(2) of CX over 24 h, followed by zero-order release of 0.35 ± 0.04 μg/cm(2)/day for another week. Although the CX concentrations released were below the reported in vitro cytotoxicity limit (5 μg/mL over 24 h) for human dermal fibroblasts, they killed 4 log(10) counts of pathogenic bacteria Staphylococcus aureus in solution. The CX/PEMs could be stamped onto Biobrane with high efficiency to provide CX release kinetics and in vitro antibacterial activity similar to that on PDMS stamps. In a full-thickness 'splinted' dermal wound-model in normal wild-type mice, the CX-functionalized Biobrane showed no decrease in either its adherence to the wound-bed or wound closure rate over 14 days. The murine wounds topically inoculated with ∼10(5) CFU/cm(2) of S. aureus and treated with CX-functionalized Biobrane demonstrated a 3 log(10) decrease in the wound's bacterial burden within 3 days, compared to persistent bacterial colonization found in wounds treated with unmodified Biobrane (n = 10 mice, p < 0.005). Overall, this study presents a promising approach to prevent bacterial colonization in wounds under biologic dressings.

New materials and devices for preventing catheter-related infections

Catheters are the leading source of bloodstream infections for patients in the intensive care unit (ICU). Comprehensive unit-based programs have proven to be effective in decreasing catheter-related bloodstream infections (CR-BSIs). ICU rates of CR-BSI higher than 2 per 1,000 catheter-days are no longer acceptable. The locally adapted list of preventive measures should include skin antisepsis with an alcoholic preparation, maximal barrier precautions, a strict catheter maintenance policy, and removal of unnecessary catheters. The development of new technologies capable of further decreasing the now low CR-BSI rate is a major challenge. Recently, new materials that decrease the risk of skin-to-vein bacterial migration, such as new antiseptic dressings, were extensively tested. Antimicrobial-coated catheters can prevent CR-BSI but have a theoretical risk of selecting resistant bacteria. An antimicrobial or antiseptic lock may prevent bacterial migration from the hub to the bloodstream. This review discusses the available knowledge about these new technologies.