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Management of postirradiation sepsis
Itzhak Brook1, Thomas B Elliott, G David Ledney
1Radiation Medicine Department, Armed Forces Radiobiology Research Institute, 8901 Wisconsin Avenue, Bethesda, MD 20889-5603, USA.
Military Medicine
|March 5, 2002
Summary
Ionizing radiation severely impacts gut bacteria, increasing infection risk. Quinolones effectively manage Gram-negative infections and improve survival after radiation exposure.
Area of Science:
- Microbiology
- Immunology
- Radiation Biology
Background:
- Ionizing radiation compromises immune defenses, increasing susceptibility to infections from internal and external microbes.
- Radiation exposure drastically alters gut microbiota composition, reducing aerobic and anaerobic bacteria while promoting Enterobacteriaceae proliferation.
Purpose of the Study:
- To investigate the effects of ionizing radiation on gut microbiota and evaluate antimicrobial strategies for managing subsequent infections.
- To assess the efficacy of quinolones and penicillin in preventing and treating infections post-irradiation.
Main Methods:
- Mice were exposed to lethal doses of cobalt-60 gamma radiation.
- Gut bacterial populations (aerobic, anaerobic, Enterobacteriaceae) were quantified over 12 days.
- Treatment efficacy of quinolones and penicillin was evaluated for endogenous and exogenous infections.
Main Results:
- Radiation reduced overall bacterial counts but led to a significant increase in Enterobacteriaceae, correlating with bacterial translocation and bacteremia.
- Quinolones effectively controlled systemic Gram-negative infections.
- Penicillin supplementation reduced treatment failures caused by Streptococci, enhancing survival.
Conclusions:
- Quinolones show promise for managing endogenous and exogenous infections after irradiation due to their ability to inhibit gut pathogens while preserving anaerobic flora.
- Coadministration of antimicrobials targeting anaerobes may be necessary for polymicrobial infections.
- The route of administration and selective pathogen inhibition make quinolones valuable therapeutic agents in radiation-induced infections.