Related Experiment Videos
Gentamicin increases the efficacy of vancomycin against penicillin-resistant pneumococci in the rabbit meningitis
Philippe Cottagnoud1, Cynthia M Gerber, Marianne Cottagnoud
1Department of Internal Medicine, Inselspital, 3010 Bern, Switzerland. pcottagn@insel.ch
Abstract:
In experimental meningitis a single dose of gentamicin (10 mg/kg of body weight) led to gentamicin levels in around cerebrospinal fluid (CSF) of 4 mg/liter for 4 h, decreasing slowly to 2 mg/liter 4 h later. The CSF penetration of gentamicin ranged around 27%, calculated by comparison of areas under the curve (AUC in serum/AUC in CSF). Gentamicin monotherapy (-1.24 log(10) CFU/ml) was inferior to vancomycin monotherapy (-2.54 log(10) CFU/ml) over 8 h against penicillin-resistant pneumococci. However, the combination of vancomycin with gentamicin was significantly superior (-4.48 log(10) CFU/ml) compared to either monotherapy alone. The synergistic activity of vancomycin combined with gentamicin was also demonstrated in vitro in time-kill assays.
Insights
Gentamicin shows limited cerebrospinal fluid penetration in experimental meningitis. Combining vancomycin with gentamicin significantly enhances treatment efficacy against penicillin-resistant pneumococci, demonstrating synergistic activity.
Area of Science:
- Pharmacology
- Infectious Diseases
- Microbiology
Background:
- Antibiotic resistance in meningitis poses a significant clinical challenge.
- Understanding drug penetration into the cerebrospinal fluid (CSF) is crucial for effective treatment.
- Penicillin-resistant *Streptococcus pneumoniae* is a common cause of bacterial meningitis.
Purpose of the Study:
- To evaluate the CSF penetration of gentamicin in experimental meningitis.
- To compare the efficacy of gentamicin monotherapy, vancomycin monotherapy, and a combination therapy against penicillin-resistant pneumococci in experimental meningitis.
Main Methods:
- Experimental meningitis model in animals.
- Pharmacokinetic analysis of gentamicin in serum and CSF.
- In vitro time-kill assays to assess synergistic activity.
- Bactericidal activity measured by log(10) CFU/ml reduction over 8 hours.
Main Results:
- Gentamicin achieved CSF concentrations of 4 mg/L, with 27% CSF penetration based on AUC.
- Gentamicin monotherapy was less effective than vancomycin monotherapy against penicillin-resistant pneumococci.
- The combination of vancomycin and gentamicin demonstrated significantly superior bactericidal activity compared to monotherapy.
Conclusions:
- Gentamicin exhibits moderate CSF penetration in experimental meningitis.
- Combination therapy with vancomycin and gentamicin is highly effective and synergistic against penicillin-resistant pneumococci.
- This combination therapy offers a promising strategy for treating resistant bacterial meningitis.