Related Experiment Video
Updated: Sep 20, 2026
A Catheter-Related Candida albicans Infection Model in Mouse
Published on: March 22, 2024
Comparison of microbial adherence to antiseptic and antibiotic central venous catheters using a novel agar
Trupti A Gaonkar1, Shanta M Modak
1College of Physicians and Surgeons, Department of Surgery, 630 West 168th Street, New York, NY 10032, USA.
Abstract:
An agar subcutaneous infection model (agar model), which simulates the rat subcutaneous infection model (rat model), was developed to assess the ability of antimicrobial catheters to resist microbial colonization. The catheters were implanted in the agar and rat models and the insertion sites were infected immediately or on day 7, 14 or 21 post-implantation. The catheters implanted in the agar model were transferred to fresh media one day before infection on day 7, 14 or 21. The efficacy of chlorhexidine and silver sulfadiazine impregnated (CS) catheters, CS catheters with higher levels of chlorhexidine (CS+ catheters), minocycline-rifampicin (MR) catheters and silver catheters against Staphylococcus aureus and rifampicin-resistant Staphylococcus epidermidis RIF-r2 was compared in the agar and rat models. No significant difference in the adherence or the drug release was found between the in vitro and in vivo models. In both models, CS+ and MR catheters were effective against S. aureus even when infected on day 14, whereas CS catheters were colonized when challenged on day 7. CS+ catheters were effective against S. epidermidis RIF-r2, whereas MR catheters showed adherence when infected on day 7. CS+ catheters prevented colonization of all the organisms including, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans in the agar model, whereas MR catheters were effective only against S. aureus and S. epidermidis strains. Silver catheters were ineffective against all the organisms. The agar model may be used to predict the in vivo efficacy of antimicrobial catheters against various pathogens.
Insights
A novel agar model effectively predicts antimicrobial catheter efficacy against microbial colonization, mirroring results from rat models. This in vitro method can assess catheter performance against various pathogens, aiding in the development of infection-resistant medical devices.
Area of Science:
- Biomaterials Science
- Infectious Diseases
- Medical Device Development
Background:
- Catheter-associated infections are a significant clinical challenge.
- Developing effective antimicrobial catheters is crucial for patient safety.
- Existing in vivo models for testing antimicrobial catheters are complex and costly.
Purpose of the Study:
- To develop and validate an agar subcutaneous infection model (agar model) that simulates a rat subcutaneous infection model (rat model).
- To assess the efficacy of various antimicrobial catheters against bacterial and fungal pathogens using both agar and rat models.
- To determine if the agar model can reliably predict the in vivo performance of antimicrobial catheters.
Main Methods:
- Catheters (chlorhexidine and silver sulfadiazine impregnated [CS], CS with higher chlorhexidine [CS+], minocycline-rifampicin [MR], and silver) were implanted in agar and rat models.
- Infection was introduced at various time points post-implantation (immediately, day 7, 14, 21).
- Microbial adherence and drug release were compared between models; catheter efficacy against Staphylococcus aureus, Staphylococcus epidermidis RIF-r2, and other pathogens was evaluated.
Main Results:
- No significant differences in adherence or drug release were observed between the agar and rat models.
- CS+ and MR catheters demonstrated efficacy against S. aureus up to 14 days post-infection in both models.
- CS+ catheters were effective against S. epidermidis RIF-r2 and a broad spectrum of other pathogens in the agar model, while MR catheters showed limited efficacy.
Conclusions:
- The agar model serves as a viable in vitro alternative to animal models for evaluating antimicrobial catheter efficacy.
- CS+ and MR catheters show promise in preventing microbial colonization, with CS+ exhibiting broader-spectrum activity.
- The agar model can accurately predict in vivo performance, facilitating the development of novel antimicrobial catheter technologies.
