679. In-vitro comparative antimicrobial activity and durability of central venous catheters coated with N-acetyl cysteine plus a broad-spectrum antibiotic
Session: Poster Abstract Session: Preventing Catheter Associated Infections
Friday, October 21, 2011
Room: Poster Hall B1
Background: Central venous catheters are responsible for 87% of bloodstream infections. These infections cause higher morbidity and mortality among critically ill patients. Formation of biofilm that normally follows colonization can shield pathogens from antimicrobial agents. As a result, some existing antimicrobial-treated catheters have limited efficacy. In this in-vitro study, we examined the activity and durability of central venous catheters coated with a combination of N-acetyl cysteine (NAC), an antibiofilm agent, plus a broad-spectrum antibiotic against both Gram-positive and Gram-negative organisms.

Methods: One-cm segments of catheters coated with a combination of NAC and gentamicin, neomycin, or levofloxacin were individually placed in human serum for up to 4 weeks. Catheter segments were removed at different time intervals and tested against methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae using a modified Kirby-Bauer method. Agar plates were streaked with suspensions of each organism, and 1-cm catheter segments were individually pressed into the agar until half embedded. Agar plates were incubated and zones of inhibition (ZI) were measured 24 to 48 hours after incubation.

Results: At baseline (no serum exposure), all coated catheters had effective ZI (ZI≥15 mm) against all tested organisms. However, only catheter segments coated with a combination of NAC and levofloxacin displayed sustained effective antimicrobial activity for all four tested organisms at 4 weeks. NAC/neomycin coated catheters did not produce any zones at two weeks and beyond for Gram-negative organisms. NAC/gentamicin-coated catheter segments showed effective zones of inhibition for all four tested organisms for up to 7 days. The efficacy of NAC/gentamicin-coated catheters continued only against MRSE for up to 4 weeks.

Conclusion: Catheters coated with a combination of antibiofilm agent NAC and a broad-spectrum antibiotic can protect against initial bacterial colonization. However, only NAC/levofloxacin displayed sustained and broad spectrum of activity against both Gram-positive and Gram-negative bacteria for up to four weeks.

Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

Mohammad D. Mansouri, 1,2, Richard Hull2, Charles Stager, PhD1,3 and Rabih O. Darouiche1,2, (1)Michael E. DeBakey VA Medical Center, Houston, TX, (2)Baylor College of Medicine, Houston, TX, (3)Baylor College of Medicine , Houston, TX


M. D. Mansouri, Baylor College of Medicine: Employee and I am the co-inventor a patent, assigned to my employer, Baylor College of Medicine, that describes the coating of catheters. Currently, there is no licensing activity., Salary

R. Hull, None

C. Stager, None

R. O. Darouiche, Baylor College of Medicine: Employee and I have patent that describes the use of N-acetyl cysteine on devices and the use of certain methods for coating devices. I have assigned these patents to my employer Baylor College of Medicine., Salary

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