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Sepsis of vascular catheters. II: In vitro disinfection of colonized tubing
M B Dennis1, D R Jones, F C Tenover
1Seattle Veterans Administration Medical Center, Washington 98108.
Abstract:
Preparatory to development of in situ disinfection of implanted catheters, silicone rubber tubing colonized by incubation with Staphylococcus aureus, Staphylococcus epidermidis, or Klebsiella pneumoniae was used to test the efficacy of various chemicals in vitro. Protocols sterilizing all segments colonized for 24 h (n = 30) were immersion into 50% povidone iodine for 5 and 60 min, 100% povidone iodine for 5, 15, and 60 min, 1.2 x 10(3) ppm chlorine dioxide for 15 and 60 min, and 1.2 x 10(3) ppm chlorine dioxide buffered to pH 5.1 for 60 min. Immersion in up to 2% chlorhexidine, 7.4% formaldehyde, or 6% sodium hypochlorite for up to 60 min failed to sterilize all segments. None of 117 control segments were sterilized. Segments colonized for seven days were sterilized by immersion into 100% povidone iodine for 15 or 60 min. Use of 1.2 x 10(3) ppm chlorine dioxide for 60 min sterilized 97% of segments tested. Lower concentrations and shorter exposure times failed to sterilize all segments. Eighteen silicone rubber catheters, colonized on the outer surface, were all sterilized within 24 h by a chlorine dioxide solution placed in the lumen and diffusing through the wall to kill the bacteria.
Insights
Povidone iodine and chlorine dioxide effectively disinfect silicone rubber catheters colonized with bacteria. These disinfectants offer promising solutions for in situ catheter disinfection, crucial for preventing infections.
Area of Science:
- Biomedical Engineering
- Infectious Diseases
- Materials Science
Background:
- Implanted catheters are prone to bacterial colonization, leading to device-associated infections.
- Current disinfection methods for implanted devices are limited, necessitating development of in situ strategies.
- Staphylococcus aureus, Staphylococcus epidermidis, and Klebsiella pneumoniae are common pathogens causing catheter-related infections.
Purpose of the Study:
- To evaluate the in vitro efficacy of various chemical disinfectants for silicone rubber tubing colonized by common bacterial pathogens.
- To identify optimal disinfection protocols for potential in situ application on implanted catheters.
Main Methods:
- Silicone rubber tubing segments were colonized with Staphylococcus aureus, Staphylococcus epidermidis, or Klebsiella pneumoniae.
- Colonized segments were immersed in various concentrations and durations of povidone iodine, chlorine dioxide, chlorhexidine, formaldehyde, and sodium hypochlorite.
- Sterilization efficacy was assessed by culturing bacterial growth from the treated segments.
Main Results:
- 100% povidone iodine for 15-60 minutes and 1.2 x 10(3) ppm chlorine dioxide for 60 minutes sterilized all segments colonized for 24 hours.
- Chlorhexidine, formaldehyde, and sodium hypochlorite failed to sterilize all segments under tested conditions.
- 100% povidone iodine sterilized 7-day colonized segments, and 60-minute chlorine dioxide treatment sterilized 97% of segments.
- A chlorine dioxide solution within the lumen sterilized externally colonized silicone rubber catheters within 24 hours.
Conclusions:
- Povidone iodine and chlorine dioxide demonstrate significant potential for in situ disinfection of colonized implanted catheters.
- Optimized protocols involving specific concentrations and exposure times are crucial for effective sterilization.
- Further research is warranted to translate these in vitro findings to clinical applications for preventing catheter-associated infections.