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The modulation by fresh and spent peritoneal dialysis fluids of antibiotic kinetics directed against Staphylococcus
G K Richards1, G B Kostiner, R F Gagnon
1South Saskatchewan Hospital Centre, Regina, Canada.
Abstract:
The presence of CAPD peritoneal catheters has an association with S. epidermidis infections which are relatively resistant to antibiotic therapy. This resistance has been ascribed to the formation by the bacteria of a protective matrix on the catheter surface enclosing the bacteria to form a bacterial biofilm. The rate of action of 14 antibiotics on standardized S. epidermidis bacterial biofilms over a 5 day exposure period and the modifying effects of fresh and spent peritoneal dialysis fluids were assayed. There were significant differences in the rates of antibiotic action. Fresh dialysis solution markedly augmented rifampin activity, and to a lesser extent, vancomycin, cloxacillin and teicoplanin but antagonized ciprofloxacin. Spent dialysis fluid generally augmented the activity of antibiotics, notably cloxacillin and cephalothin. Rifampin was bactericidal in both fresh and spent dialysis fluids. Fusidic acid was a poor performer in all tests.
Insights
Continuous ambulatory peritoneal dialysis (CAPD) catheter infections by S. epidermidis are antibiotic-resistant due to biofilms. Dialysis fluids modify antibiotic effectiveness, with rifampin showing bactericidal activity in both fresh and spent fluids.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- S. epidermidis forms biofilms on CAPD catheters, leading to antibiotic resistance.
- Bacterial biofilms pose a significant challenge in managing CAPD-related infections.
Purpose of the Study:
- To evaluate the efficacy of 14 antibiotics against S. epidermidis biofilms.
- To assess the impact of peritoneal dialysis fluids on antibiotic activity.
Main Methods:
- Standardized S. epidermidis biofilms were exposed to 14 antibiotics for 5 days.
- The influence of fresh and spent peritoneal dialysis fluids on antibiotic action was measured.
Main Results:
- Significant variations in antibiotic efficacy were observed.
- Fresh dialysis fluid enhanced rifampin, vancomycin, cloxacillin, and teicoplanin activity, but reduced ciprofloxacin efficacy.
- Spent dialysis fluid generally improved antibiotic activity, especially for cloxacillin and cephalothin. Rifampin was bactericidal in all conditions; fusidic acid was ineffective.
Conclusions:
- Peritoneal dialysis fluids can modulate antibiotic effectiveness against S. epidermidis biofilms.
- Rifampin demonstrates consistent bactericidal activity, making it a promising agent for CAPD-related infections.
- Understanding these interactions is crucial for optimizing antibiotic therapy in CAPD patients.