From the Research
Characteristics of Citrobacter koseri
- Citrobacter koseri is a gram-negative bacillus (GNB) 1
- It is a motile, non-spore-forming facultative anaerobic bacillus belonging to the Enterobacteriaceae family 2
- C. koseri is a non-sporulating, motile, gram-negative, facultative anaerobic bacteria 3
- It typically utilizes citrate as the sole carbon source and constitutes part of the normal gastrointestinal flora in humans and animals 2
Pathogenicity and Infections
- Citrobacter koseri is an opportunistic pathogen that occurs in neonates and immunocompromised patients 1
- It has been implicated in nosocomial settings leading to infections involving the urinary tract, respiratory tract, liver, biliary tract, meninges, and bloodstream 1
- C. koseri has been known to cause meningitis and brain abscess in neonates and immunocompromised individuals 4
- It has also been reported to cause infective endocarditis in immunocompetent adults 5
- Osteomyelitis secondary to C. koseri is very rare, but has been reported in a healthy young man with no identifiable risk factors 3
Antibiotic Resistance and Treatment
- Citrobacter koseri is becoming more recognized due to its inherent resistance to ampicillin and emerging drug resistance to beta lactams and aminoglycosides requiring carbapenem therapy 1
- The American Heart Association (AHA) and Infectious Diseases Society of America (IDSA) recommend the use of combination antibiotic therapy with a beta-lactam and either an aminoglycoside or fluoroquinolones for 6 weeks to treat IE due to non-HACEK GNB 1