What are the risk factors for Citrobacter koseri urinary tract infections (UTIs)?

Risk Factors for Citrobacter koseri Urinary Tract Infections

The primary risk factors for Citrobacter koseri urinary tract infections include urinary tract obstruction, foreign bodies, catheterization, immunosuppression, diabetes mellitus, healthcare-associated exposures, and underlying urological abnormalities. 1

General Risk Factors for Complicated UTIs Including C. koseri

C. koseri is an opportunistic gram-negative pathogen that typically causes infections in patients with predisposing factors. The European Association of Urology guidelines identify several risk factors associated with complicated UTIs that apply to C. koseri infections:

• Structural or functional abnormalities of the urinary tract:

  • Obstruction at any site in the urinary tract 1
  • Foreign body presence (including catheters) 1
  • Incomplete voiding 1
  • Vesicoureteral reflux 1
  • Recent history of urological instrumentation 1

• Host-related factors:

  • Male gender (UTIs in males are generally considered complicated) 1
  • Pregnancy 1
  • Diabetes mellitus 1
  • Immunosuppression 1, 2

• Microbiological factors:

  • Healthcare-associated infections 1
  • Extended-spectrum β-lactamase (ESBL)-producing organisms 1
  • Multidrug-resistant organisms 1

Catheter-Associated UTI Risk Factors

Catheter-associated UTIs represent a significant risk for C. koseri infection:

• Catheterization duration is the most important risk factor for developing catheter-associated UTIs 1
• Female gender increases risk (adjusted odds ratio = 1.39) 1
• Advanced age (risk increases approximately 1% per day) 1
• Prolonged hospital and intensive care unit stays 1
• Diabetes mellitus 1
• Mobility issues 1
• Neurological conditions (patients in neurologic ICUs have significantly higher risk, aOR = 11.49) 1

Specific Risk Factors for C. koseri Infections

C. koseri has particular associations with:

• Immunocompromised patients (primary target population) 2, 3
• Diabetes mellitus (significant comorbidity in case reports) 4
• Urological abnormalities (such as spina bifida with urinary diversions like ileal conduits) 5
• Presence of renal calculi (can serve as a nidus for infection) 5
• Antimicrobial resistance (C. koseri has inherent resistance to ampicillin and emerging resistance to other antibiotics) 2, 6

Clinical Implications

Understanding these risk factors is crucial for:

• Identifying high-risk patients who may benefit from preventive strategies 7
• Guiding empiric antibiotic selection when C. koseri is suspected 1, 3
• Informing the management of underlying urological abnormalities, which is mandatory for successful treatment 1

When managing patients with C. koseri UTIs, it's essential to address modifiable risk factors, particularly removing or changing catheters when clinically feasible, as this is a critical part of management 7.