A new central venous catheter cap: decreased microbial growth and risk for catheter-related bloodstream infection

Catheter-related blood stream infection (CRBI) is a major cause of morbidity and mortality, and is a source of significant healthcare expenditures in patients that require central venous catheters for intravenous nutrition, chemotherapy, and other products. The source of many catheter-related infections is contamination of the catheter hub. Herein an antimicrobial catheter cap, the AB Cap is described.

The AB Cap device is a catheter cleaning device designed to keep needleless luer valves clean by encapsulating them in a cleaning solution. This device was evaluated using an in vitro model of hub contamination with Staphylococcus aureus, Staphylococcus epidermidis (S. epidermidis), Klebsiella pneumonia (K. pneumonia), Pseudomonas aeruginosa, Escherichia coli and Candida albicans (C. albicans). Following hub contamination on days 1, 3, 5 and 7, saline was infused through the AB Cap and effluent collected from the efferent end. The effluent fluid was cultured for the index organisms, and allowed to incubate in culture for up to 7 days. Negative control caps were not contaminated and positive controls lacked cleaning solution and were contaminated.

Microbial growth developed for all index organisms, and generally within 1 day of culture growth following the first day of contamination (day 1) in effluent from all positive controls, while no growth occurred in effluent from negative controls. No growth of any organism occurred in any of the test items after the first day of contamination. Growth of three organisms was detected in two of the three test AB Caps following contamination day 3, after 1-4 days of incubation. All organisms could be cultured in the effluent from two of the three test items at contamination day 5, generally by the second day of incubation. One test item remained free of growth for the entire test period except for one organism. By day 7, this particular test item grew an additional organism and the testing was concluded. All positive growth test items remained positive on subsequent inoculations during culture of newly obtained effluent with the exception of test item A, from which effluent following inoculation on day 3 showed growth of S. epidermidis and K. pneumonia, but no growth for these organisms from effluent obtained on inoculation day 5. In addition, effluent from test item C showed growth of C. albicans from inoculation day 5, but no growth from effluent obtained on inoculation day 7. The growth of S. epidermidis from effluent of test item A from the day 3 inoculation, and C. albicans from effluent of test items B and C did not occur until day 4 of incubation, suggesting a very small amount of contamination.

An antimicrobial catheter cap is not a complete substitute for a proper catheter cleaning technique and other anti-infection precautions. However, we describe a unique catheter cap that significantly decreased the likelihood of a catheter-related infection from a non-cleaned cap in an in vitro model.