What is the treatment for Citrobacter koseri infections?

From the Guidelines

Treatment for Citrobacter koseri infections should be guided by susceptibility testing, with carbapenems such as meropenem or imipenem being recommended for severe infections, especially those caused by third-generation cephalosporin-resistant Enterobacterales (3GCephRE) 1. When considering the treatment of Citrobacter koseri infections, it's crucial to prioritize the most effective antibiotics based on the severity of the infection and the susceptibility pattern of the isolate.

• For patients with bloodstream infections (BSI) and severe infection due to 3GCephRE, a carbapenem (imipenem or meropenem) is strongly recommended as targeted therapy 1.
• For non-severe infections, piperacillin-tazobactam, amoxicillin/clavulanic acid, or quinolones may be considered under antibiotic stewardship principles 1.
• In cases of complicated urinary tract infections (cUTI), aminoglycosides or IV fosfomycin may be conditionally recommended for short durations of therapy 1.
• The use of tigecycline is not recommended for infections caused by 3GCephRE due to its low efficacy 1.
• For infections caused by carbapenem-resistant Enterobacterales (CRE), meropenem-vaborbactam or ceftazidime-avibactam may be suggested if active in vitro, with ceftiderocol considered for infections carrying metallo-beta-lactamases and/or resistant to other antibiotics 1. Key considerations in the treatment of Citrobacter koseri infections include:
• The importance of susceptibility testing to guide antibiotic choice
• The need for source control, such as drainage of abscesses or removal of infected devices
• The potential for resistance development, particularly through extended-spectrum beta-lactamases (ESBLs), which may necessitate the use of carbapenem antibiotics
• The role of antibiotic stewardship in selecting appropriate antibiotics and minimizing the risk of resistance development.

From the FDA Drug Label

1.3 Intra-Abdominal Infections Imipenem and Cilastatin for Injection, USP (I.V.) is indicated for the treatment of intra-abdominal infections caused by susceptible strains of ... Citrobacter species, ... 1.7 Skin and Skin Structure Infections Imipenem and Cilastatin for Injection, USP (I.V.) is indicated for the treatment of skin and skin structure infections caused by susceptible strains of ... Citrobacter species, ...

The treatment for Citrobacter koseri infections may include Imipenem and Cilastatin for Injection, USP (I.V.), as it is indicated for the treatment of infections caused by susceptible strains of Citrobacter species 2.

• Intra-abdominal infections
• Skin and skin structure infections may be treated with Imipenem and Cilastatin for Injection, USP (I.V.) if caused by susceptible Citrobacter species.

From the Research

Treatment Overview

• The treatment for Citrobacter koseri infections typically involves antimicrobial therapy based on the sensitivity of the pathogen microorganism 3.
• Various types of antibiotics, including aminoglycosides, carbapenems, cephalosporins, chloramphenicol, and quinolones, are used for the treatment of C. koseri infections 3.
• The rational choice of antimicrobial therapy for Citrobacter infections is a challenge for clinicians due to the sustained increase in antibacterial resistance 3.

Specific Treatment Regimens

• Combination antibiotic therapy with a beta-lactam (penicillins, cephalosporins, or carbapenems) and either an aminoglycoside or fluoroquinolones for 6 weeks is recommended for the treatment of infective endocarditis (IE) due to non-HACEK GNB, including C. koseri 4.
• Ciprofloxacin and cefotaxime have been used successfully to treat C. koseri infection in a preterm infant 5.
• Carbapenems, such as imipenem/meropenem, in combination with cefotaxime and surgical drainage, may play an important role in treating C. koseri meningitis 6.

Considerations

• 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 4.
• The mortality rate for meningitis due to Citrobacter spp. is approximately 30%, and of the infants who survive, more than 80% have some degree of mental retardation 5.
• Approximately 76% of neonatal patients infected with C. koseri develop brain abscesses 5.