Treatment Approach for Asymptomatic Citrobacter koseri Bacteriuria
Asymptomatic Citrobacter koseri bacteriuria should not be treated with antimicrobial therapy in most patient populations, as treatment provides no clinical benefit and may lead to adverse outcomes including antimicrobial resistance. 1
Definition and General Approach
- Asymptomatic bacteriuria (ASB) is defined as the presence of bacteria in a properly collected urine specimen from a person without signs or symptoms referable to urinary infection 1
- For men, ASB is defined as a clean-catch urine sample with ≥10⁵ CFU/mL of a single bacterial species, or a catheterized sample with ≥10² CFU/mL of a single species 2
- The Infectious Diseases Society of America (IDSA) strongly recommends against screening for or treating ASB in most patient populations 1
Patient Populations Where Treatment is NOT Recommended
- Premenopausal, non-pregnant women 1
- Diabetic patients 1
- Older persons living in the community 1
- Elderly institutionalized individuals 1
- Persons with spinal cord injury 1
- Patients with indwelling catheters while the catheter remains in place 1
- Renal transplant recipients beyond one month post-transplant 1
- Recipients of other solid organ transplants 1
- Men without specific risk factors 2
Rationale for Non-Treatment
- Treatment of ASB does not reduce the frequency of symptomatic infections 1, 3
- Antimicrobial therapy for ASB can lead to adverse drug effects, including Clostridioides difficile infection 1, 4
- Treatment promotes the emergence of antimicrobial-resistant organisms 1, 3
- Studies show no improvement in mortality, morbidity, or quality of life with treatment of ASB in most populations 5, 4
- The presence of pyuria accompanying ASB is not an indication for antimicrobial treatment 2
Specific Considerations for Citrobacter koseri
- C. koseri is a gram-negative bacterium that can cause opportunistic infections, particularly in immunocompromised hosts 6
- While C. koseri can be virulent in certain populations (especially neonates), asymptomatic bacteriuria with this organism follows the same management principles as other bacterial species 6
- The rational choice of antimicrobial therapy, when indicated, should be based on susceptibility testing due to increasing antimicrobial resistance in Citrobacter species 6
Limited Scenarios Where Treatment IS Recommended
- Pregnant women (to prevent complications such as pyelonephritis, low birthweight, and preterm delivery) 1, 5
- Prior to urologic procedures where mucosal bleeding is anticipated, such as transurethral resection of the prostate 1
- For patients undergoing urologic procedures with risk of mucosal trauma, the protocol includes:
- Obtaining urine culture before the procedure to guide antimicrobial therapy 1
- Initiating antibiotics shortly before the procedure (30-60 minutes prior) 1
- Using the shortest effective course of antibiotics 1, 2
- Discontinuing therapy immediately after the procedure unless an indwelling catheter remains in place 1
Special Circumstances
- For women with catheter-acquired bacteriuria that persists 48 hours after catheter removal, treatment may be considered, though evidence is limited 1
- For patients with delirium or falls, current guidelines recommend assessment for other causes rather than treating ASB, as treatment has not been shown to improve outcomes 1, 4
Common Pitfalls in Management
- Treating ASB based on positive urine culture alone without symptoms 3, 4
- Misinterpreting nonspecific symptoms (such as cloudy or malodorous urine) as indications for treatment 1, 4
- Continuing antimicrobial therapy beyond necessary duration when treatment is indicated 1, 2
- Failing to distinguish between ASB and symptomatic UTI in patients with atypical presentations 1