What are the American Academy of Pediatrics (AAP) guidelines for treating Shigella and E. coli infections in a 19-month-old child?

AAP Guidelines for Treatment of Shigella and E. coli in a 19-Month-Old Child

For Shigella infections in a 19-month-old child, azithromycin is the first-line treatment, while antibiotics should be avoided for STEC O157 and other Shiga toxin 2-producing E. coli infections due to increased risk of hemolytic uremic syndrome. 1, 2

Shigella Infection Treatment

First-line Treatment

• Azithromycin: 10 mg/kg on day 1, followed by 5 mg/kg once daily for 4 days 1, 2
• Preferred over fluoroquinolones in children due to concerns about arthropathy 1

Alternative Options

• Ceftriaxone: For severe infections or when azithromycin resistance is suspected 1, 2
• Trimethoprim-sulfamethoxazole (TMP-SMX): Only if local susceptibility is confirmed
  • Dosage: 40 mg/kg sulfamethoxazole and 8 mg/kg trimethoprim per 24 hours, divided into two doses for 5 days 3
  • Not recommended for children under 2 months of age 3

Important Clinical Considerations

• Treatment should be initiated promptly after diagnosis to reduce duration of illness and bacterial shedding 2
• Most Shigella infections in young children present with watery diarrhea rather than bloody diarrhea, making clinical diagnosis challenging 4
• Molecular diagnostic methods (PCR) are significantly more sensitive than conventional stool culture for detecting Shigella (8.7% vs 0.7%) 5, 4

E. coli Infection Treatment

STEC (Shiga Toxin-Producing E. coli)

• Antibiotics should be avoided for STEC O157 and other Shiga toxin 2-producing E. coli 1, 2
• Antimicrobial therapy may increase the risk of hemolytic uremic syndrome (HUS) 1
• Antimotility agents should also be avoided in suspected STEC infections 1, 2

Enterotoxigenic/Enteropathogenic E. coli

• For non-STEC E. coli causing significant illness:
  • Azithromycin is preferred for children 1
  • TMP-SMX may be used if susceptibility is confirmed 1

Special Considerations for 19-Month-Old Children

Risk Assessment

• Young children under 3 years are at higher risk for:
  • Dehydration (59.9% vs 32.1% in older children) 6
  • Bacteremia (12% vs 5% in older children) 6
  • Mortality (16.4% vs 8.2% in older children) 6

Indications for Empiric Treatment

• Empiric treatment should be considered for:
  • Infants with fever documented in a medical setting
  • Bloody diarrhea with abdominal pain
  • Signs of sepsis or severe illness 1

Diagnostic Approach

• Stool testing should be performed for Shigella, Salmonella, Campylobacter, Yersinia, C. difficile, and STEC in symptomatic children 1
• Blood cultures should be obtained if there are signs of septicemia 1, 7
• Tests that can detect Shiga toxin (or encoding genes) and distinguish E. coli O157:H7 from other STEC should be used 1

Monitoring and Follow-up

• Monitor for dehydration, which increases risk of life-threatening illness 1
• Reassess patients who do not respond to initial therapy within 72 hours 2
• Be aware of increasing resistance patterns globally, particularly to fluoroquinolones, ampicillin, and TMP-SMX 1, 2
• Consider longer treatment duration (7-10 days) for severe cases or those with complications 2, 7

Remember that prompt diagnosis and appropriate treatment are crucial for managing these infections in young children, while avoiding unnecessary antibiotics for STEC infections that could increase the risk of serious complications.