Treatment of Klebsiella UTI in Infants: ISPn Guidelines
For infants with Klebsiella urinary tract infections, empirical treatment should follow age-specific recommendations: ampicillin plus ceftazidime or gentamicin for infants 8-21 days old, ceftriaxone for those 22-60 days old, with oral options like cephalexin or cefixime available for infants older than 28 days. 1
Age-Based Treatment Algorithm
Infants 8-21 days old:
- First-line therapy:
- Ampicillin IV/IM (150 mg/kg/day divided every 8h) AND
- Either ceftazidime IV/IM (150 mg/kg/day divided every 8h) OR
- Gentamicin IV/IM (4 mg/kg/dose every 24h) 1
Infants 22-28 days old:
- First-line therapy:
- Ceftriaxone IV/IM (50 mg/kg/dose every 24h) 1
Infants 29-60 days old:
- Parenteral option:
- Ceftriaxone IV/IM (50 mg/kg/dose every 24h)
- Oral options (for infants >28 days):
- Cephalexin 50-100 mg/kg/day in 4 doses OR
- Cefixime 8 mg/kg/day in 1 dose 1
Special Considerations for Klebsiella UTIs
ESBL-Producing Klebsiella
If ESBL-producing Klebsiella is suspected or confirmed:
- First-line treatment: Carbapenems (meropenem or imipenem) 2
- Alternative if susceptible: Gentamicin at 7.5 mg/kg/day divided every 8 hours with monitoring of renal function and drug levels 2
- Important note: Standard cephalosporins will be ineffective against ESBL-producing organisms 2
Treatment Duration
- Complete a 7-14 day course of antibiotics for UTI 2
- For pyelonephritis or complicated UTI, a 10-14 day course is recommended 2, 3
Diagnostic Confirmation
- Definitive UTI diagnosis requires:
- Pyuria AND ≥50,000 CFU/mL of a single uropathogen, OR
- Pure growth of 250,000 CFUs/mL with urinalysis showing bacteriuria or pyuria 2
- Obtain urine specimen via catheterization or suprapubic aspiration before administering antibiotics 2
Monitoring and Follow-up
- Clinical improvement should be seen within 48-72 hours of appropriate therapy 2
- If symptoms persist despite appropriate antibiotic therapy, consider imaging and reassessment of treatment 2
- Renal and bladder ultrasound (RBUS) should be performed after the first febrile UTI 2
Antimicrobial Resistance Considerations
- Local antibiogram data should guide empirical therapy choices 1
- Klebsiella species have shown increasing resistance to ampicillin (95.9% in some studies) and growing resistance to gentamicin (52.6%) 4, 5
- Resistance patterns vary by region and have been increasing over time, with multidrug resistance reported in 11.8% of uropathogens in young infants 5
Prevention of Recurrence
- Consider antibiotic prophylaxis in select cases with high-grade vesicoureteral reflux (grades III-IV) or recurrent infections 2
- Instruct parents to seek prompt medical evaluation (within 48 hours) for future febrile illnesses 2
The management of Klebsiella UTIs in infants requires prompt diagnosis and appropriate antibiotic therapy based on age and local resistance patterns. While empirical therapy is necessary initially, treatment should be adjusted based on culture and sensitivity results to ensure optimal outcomes and prevent complications.