From the Guidelines
The best treatment approach for a wound culture positive for Citrobacter koseri typically involves fluoroquinolones such as ciprofloxacin (500 mg orally twice daily) or levofloxacin (750 mg orally once daily) for 7-14 days, depending on wound severity, as guided by antimicrobial susceptibility testing 1.
Key Considerations
- Citrobacter koseri is a gram-negative bacillus that can cause opportunistic infections, particularly in immunocompromised patients or those with underlying conditions.
- Treatment should be based on the severity of the infection and the likely etiologic agent(s), with consideration of recent antibiotic therapy and local antibiotic susceptibility data, especially the prevalence of resistant organisms 1.
- Broad-spectrum empirical therapy may be indicated for severe infections, pending culture results and antibiotic susceptibility data 1.
- Wound care is equally important and should include regular cleaning, debridement of necrotic tissue if present, and appropriate dressing changes.
- The duration of antibiotic therapy should be continued until there is evidence that the infection has resolved, but not necessarily until a wound has healed, with suggestions ranging from 1-2 weeks for mild infections to 2-4 weeks for moderate and severe infections 1.
Treatment Options
- Fluoroquinolones: ciprofloxacin (500 mg orally twice daily) or levofloxacin (750 mg orally once daily) for 7-14 days.
- Third-generation cephalosporins: ceftriaxone (1-2 g IV daily) or cefotaxime (1-2 g IV every 8 hours).
- Carbapenems: meropenem (1 g IV every 8 hours) for more severe infections.
Important Notes
- Antimicrobial susceptibility testing is crucial for optimizing treatment, as Citrobacter koseri may produce beta-lactamases, potentially conferring resistance to some antibiotics.
- If the patient has systemic symptoms like fever or elevated white blood cell count, broader coverage may be needed initially until culture results are finalized.
- Providing optimal wound care, in addition to appropriate antibiotic treatment of the infection, is crucial for healing 1.
From the FDA Drug Label
Gentamicin Injection, USP is indicated in the treatment of serious infections caused by susceptible strains of the following microorganisms: ... Citrobacterspecies The following bacteria are usually resistant to the aminoglycosides, including gentamicin: ... most enterococcal species, and anaerobic organisms, such as Bacteroidesspecies and Clostridiumspecies. Gentamicin has been shown to be active against most of the following bacteria, both in vitroand in clinical infections ... Citrobacterspecies
Best Treatment Approach: The best treatment approach for a wound culture positive for Citrobacter koseri is gentamicin (IV), as it has been shown to be active against Citrobacter species in vitro and in clinical infections 2, 2.
- Key Considerations:
- Obtain specimens for bacterial culture to isolate and identify causative organisms and determine their susceptibility to gentamicin.
- Consider the severity of the infection and the results of susceptibility tests when deciding to continue therapy with gentamicin.
- If the causative organisms are resistant to gentamicin, other appropriate therapy should be instituted.
From the Research
Treatment Approach for Citrobacter koseri Infection
The best treatment approach for a wound culture positive for Citrobacter koseri involves antimicrobial therapy based on the sensitivity of the pathogen microorganism 3. Various types of antibiotics, including:
- Aminoglycosides
- Carbapenems
- Cephalosporins
- Chloramphenicol
- Quinolones
Antibiotic Treatment Options
Specific antibiotic treatment options for systemic infection or meningitis caused by C. koseri include:
- Ciprofloxacin and meropenem, which have favorable sensitivity data, penetration into neutrophils and the CNS, and favorable toxicity profiles 4
- Imipenem/meropenem and surgical drainage, which may play an important role in treating C. koseri meningitis 5
Diagnosing Wound Infections
When diagnosing wound infections, swab cultures can be used to identify the causative organisms and guide antibiotic therapy when clinical suspicion of an infection exists 6, 7. However, tissue biopsy is considered the gold standard to diagnose infection. The Levine technique is a reliable method to determine microbial load in the wound bed 7.
Key Considerations
Key considerations for treating C. koseri infections include: