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Antibiotic therapy of fulminant E. coli K1 sepsis in infant rabbits
Insights
Ampicillin, moxalactam, and chloramphenicol effectively treated E. coli K1 sepsis and meningitis in infant rabbits. These antibiotics reduced infection incidence and mortality compared to cephalothin or saline controls.
Area of Science:
- Neonatal research
- Infectious disease modeling
- Pharmacology
Background:
- Infant sepsis and meningitis caused by E. coli K1 pose significant mortality risks.
- Developing effective treatments for neonatal infections is critical.
Purpose of the Study:
- To compare the clinical and bacteriologic efficacy of ampicillin, moxalactam, cephalothin, and chloramphenicol.
- To evaluate antibiotic effectiveness in a rabbit model of E. coli K1 sepsis and meningitis.
Main Methods:
- An infant rabbit model was established to simulate E. coli K1 sepsis and meningitis.
- Antibiotic treatments were initiated 4 hours post-infection.
- Bacteremia, meningitis incidence, and mortality rates were assessed.
Main Results:
- Ampicillin, moxalactam, and chloramphenicol significantly reduced bacteremia and meningitis compared to cephalothin or saline (P < 0.02).
- Mortality rates were lower in groups treated with ampicillin, moxalactam, or chloramphenicol (64-82%) versus cephalothin or saline (100%).
- Moxalactam showed no therapeutic advantage over ampicillin or chloramphenicol in this model.
Conclusions:
- Ampicillin, moxalactam, and chloramphenicol demonstrate efficacy in treating severe E. coli K1 infections in neonates.
- Cephalothin was ineffective, with undetectable levels in cerebrospinal fluid.
- Further research may explore optimizing antibiotic strategies for neonatal sepsis and meningitis.
Abstract:
A model of overwhelming E. coli K1 sepsis and early meningitis was developed in infant rabbits and used to compare clinical and bacteriologic efficacy of ampicillin, moxalactam, cephalothin and chloramphenicol. Intraperitoneal injection of 10(7) E. coli K1 into 1- or 2-wk-old rabbits produced a rapidly progressive infection which, if left untreated, produced bacteremia in 100% of animals, meningitis in 78%, and mortality in 100%. Therapy was initiated 4 h after ip infection at which time mean bacterial concentration (log10 CFU/ml) ranged from 4.4-4.8 in the blood and from 1.8-2.3 in the cerebral spinal fluid (CSF). Pre-treatment frequency of bacteremia (100%) and meningitis (17-23%) was similar for all experimental groups. Antibiotic concentrations in blood and CSF 2 h after a dose exceeded the E. coli minimum inhibitory concentration with the exception of CSF cephalothin, which was undetectable. Moxalactam, ampicillin, and chloramphenicol significantly reduced the incidence of bacteremia and meningitis relative to cephalothin or saline controls (P less than 0.02). Mortality rates among the former three groups were high (64-82%) but significantly less than in saline or cephalothin-treated rabbits (100%). In this neonatal model of fulminant sepsis with early meningitis, moxalactam provided no therapeutic advantage over ampicillin or chloramphenicol.