What is the recommended treatment for a 12-year-old male with a urinary tract infection (UTI) caused by Streptococcus agalactiae?

Treatment of Streptococcus agalactiae UTI in a 12-year-old Male

For a 12-year-old male with a urinary tract infection caused by Streptococcus agalactiae, the recommended treatment is an oral cephalosporin such as cefpodoxime 10 mg/kg/day divided in two doses for 7-14 days. 1

Initial Assessment and Classification

• UTIs in males are considered complicated UTIs due to anatomical factors, requiring more careful management and potentially longer treatment duration 1
• S. agalactiae (Group B Streptococcus) is susceptible to beta-lactam antibiotics, with amoxicillin showing greater activity than ampicillin in vitro 2
• The patient's clinical status should be evaluated to determine if parenteral therapy is needed initially:
  • Signs of systemic illness (high fever, vomiting, dehydration) would warrant consideration of initial parenteral therapy 1
  • If the patient appears well and can tolerate oral medications, oral therapy is appropriate 1

Antibiotic Selection

First-line options:

• Oral cephalosporins are recommended for pediatric UTIs and are effective against S. agalactiae:
  • Cefpodoxime: 10 mg/kg/day divided in 2 doses (not to exceed adult dose) 1
  • Cefixime: 8 mg/kg/day as a single daily dose 1
  • Cephalexin: 50-100 mg/kg/day divided in 4 doses 1

Alternative options:

• Amoxicillin-clavulanate: 20-40 mg/kg/day divided in 3 doses 1
  • Amoxicillin has been shown to be 2.5 times more active than ampicillin against S. agalactiae 2
• Trimethoprim-sulfamethoxazole: 6-12 mg/kg trimethoprim and 30-60 mg/kg sulfamethoxazole per day in 2 doses 1
  • However, sulfonamides alone have poor activity against S. agalactiae, so this should only be used if susceptibility is confirmed 2

For severe infection requiring parenteral therapy:

• Ceftriaxone: 75 mg/kg every 24 hours 1
• Cefotaxime: 150 mg/kg per day divided every 6-8 hours 1
• Ampicillin: 100 mg/kg/day total, divided in 4 equal doses for children weighing 20 kg or less 3

Duration of Treatment

• Treatment should be continued for 7-14 days 1
• For males, a longer duration (14 days) may be warranted as prostatitis cannot always be excluded 1
• Shorter courses (1-3 days) have been shown to be inferior for febrile UTIs 1

Follow-up Recommendations

• Urine culture should be obtained before initiating therapy to confirm the diagnosis and guide treatment 1
• Clinical improvement should be expected within 48-72 hours of initiating appropriate therapy 1
• Consider renal and bladder ultrasonography to detect any underlying anatomical abnormalities, as UTI in males is considered complicated 1
• A follow-up urine culture after completing treatment may be warranted to ensure eradication of the infection 3

Special Considerations

• Nitrofurantoin should not be used for this patient despite in vitro activity against some strains of S. agalactiae, as it does not achieve adequate serum concentrations to treat potential pyelonephritis 1, 2
• Local antibiotic resistance patterns should be considered when selecting empiric therapy 1
• S. agalactiae UTIs in males are uncommon and may suggest an underlying urological abnormality that requires further evaluation 1, 4

Remember that treatment should be adjusted based on culture results and clinical response. If symptoms persist despite appropriate antibiotic therapy, further investigation for anatomical abnormalities or complications is warranted.