An alcohol hand rub containing a synergistic combination of an emollient and preservatives: prolonged activity against transient pathogens

A new alcohol-based hand antiseptic (Octoxy hand rub) containing a synergistic combination of an emollient (Octoxyglycerine) and preservatives was developed and evaluated for immediate and prolonged activity against transient bacteria. The in vitro and in vivo antimicrobial efficacy was compared with other alcohol hand rubs containing preservative/antimicrobial (Prevacare and Avagard). In vitro evaluation was carried out using a tube-dilution method and a pig-skin model. Rapid and prolonged efficacy in vivo was evaluated against Staphylococcus epidermidis on the hands of volunteers. Octoxy hand rub was 100% effective in rapidly killing pathogens including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium in vitro. In volunteers, all three hand rubs gave a significant reduction in microbial count within 15s. Octoxy hand rub showed significantly higher efficacy against S. aureus and Escherichia coli than Avagard and Prevacare 15 min after application to the pig-skin model, and against S. epidermidis in both the pig-skin model and in volunteers. Use of Octoxy hand rub with broad-spectrum immediate and prolonged antimicrobial activity may be a very effective way of improving hand hygiene without exposing the hands to higher concentrations of antimicrobials.

Development of an infection-resistant LVAD driveline: a novel approach to the prevention of device-related infections

BACKGROUND

Infection remains the single most important challenge to extended left ventricular assist device (LVAD) use and often arises from the percutaneous driveline exit site. We evaluated the ability of an LVAD driveline prototype impregnated with chlorhexidine, triclosan, and silver sulfadiazine to resist bacterial and fungal colonization.

METHODS

The spectrum and duration of antimicrobial activity were evaluated in vitro by daily transfer of driveline segments embedded on agar plates inoculated with 10(8) colony-forming units (CFU) of Staphylococcus aureus (S. aureus), Staphlococcus epidermidis, Enterobacter aerogenes, Psuedomonas aeruginosa, and Candida albicans, and then measuring zones of inhibition around the sample subsequent to 24 hours of incubation at 37 degrees C. Antimicrobial activity was demonstrated against all organisms for greater than 14 days, and for over 21 days for gram-positive bacteria. To demonstrate in vivo efficacy of the treated driveline, 3-cm segments of driveline were implanted in the dorsal and ventral surface of rats. The exit site was inoculated with 10(6) CFU of S. aureus. After 7 days, driveline segments were aseptically explanted and assayed for bacterial colonization and retention of antimicrobial activity. One hundred percent of control segments were colonized (10(5) CFU S. aureus/cm) as against 13% of the test explants (< or = 330 CFU/cm; p < 0.0001).

RESULTS

Subcultures of the insertion site and driveline pocket tissue resulted in 10(3) to 10(5) CFU per swab culture for control rats and 0 to 10(2) CFU/swab for test animals. Test drivelines retained 80% of anti-S. aureus activity. Gross and histological examination of the driveline and surrounding pocket revealed minimal tissue reactivity with positive signs of tissue ingrowth.

CONCLUSION

An antimicrobial driveline may prevent early infections and facilitate ingrowth of tissue to provide long-term stability and protection against late infection.

Infection resistance of surface modified catheters with either short-lived or prolonged activity

It has been suggested that the invasion of microbes into the catheter tract occurs mainly at the time of catheter insertion. To investigate whether the presence of an antimicrobial environment during the initial period after insertion is sufficient to reduce the risk of subsequent catheter colonization and infection, we evaluated the use of benzalkonium chloride-heparin bonded (BZK-hep) central venous catheters, which exhibit short-lived surface antimicrobial activity, using a rat subcutaneous model. Bacterial adherence on these catheters was determined, seven days after challenging the insertion site with 10(6) cfu of Staphylococcus aureus. A chlorhexidine-silver sulphadiazine impregnated catheter (Arrowg+ard), with longer lasting surface antimicrobial activity, and a hydrophilic coated catheter ('Hydrocath'), were evaluated simultaneously for comparison. Unlike Arrowg+ard antiseptic catheters, BZK-hep 'Hydrocath' and control catheters had significant bacterial adherence on their surface. Arrowg+ard catheters were colonized in 19% of the animals compared with 100% in all the other groups (P < 0.05; mean cfu cm-2: control = 1.3 x 10(6), BZK-hep = 4.3 x 10(5), Hydrocath = 2 x 10(5), Arrowg+ard = 71). Our results indicate that catheters with short-lived surface antimicrobial activity are unlikely to provide long-term protection against catheter-related infection. The efficacy of Arrowg+ard catheters may be due to the initial high rate of kill and prolonged antimicrobial activity.