Does an 11-year-old healthy male require treatment for a stool culture positive for Salmonella and Escherichia coli (E. coli)?

From the Guidelines

In a healthy 11-year-old male with a stool culture positive for Salmonella and E. coli but no symptoms, treatment with antibiotics is generally not recommended. The primary approach should focus on supportive care, maintaining hydration with oral rehydration solutions or, if needed, intravenous fluids for severe dehydration. According to the 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea 1, empiric antimicrobial therapy for bloody diarrhea while waiting for results of investigations is not recommended in immunocompetent children and adults, except in specific situations.

The guidelines suggest that antibiotics are typically reserved for situations such as severe illness, invasive disease, high risk for complications (immunocompromised patients), or persistent symptoms. Using antibiotics unnecessarily can prolong bacterial shedding, increase antibiotic resistance, and potentially worsen outcomes in some bacterial infections like Salmonella 1. If the child develops severe symptoms (high fever, bloody diarrhea, signs of dehydration, or systemic illness), clinical reassessment would be warranted.

The presence of both organisms could represent normal colonization, especially for certain E. coli strains, or could indicate contaminated food exposure. Most cases of bacterial gastroenteritis in otherwise healthy children are self-limiting and resolve within 5-7 days with supportive care alone. It's also important to note that treatment of STEC O157 infections and likely non-O157 STEC infections that produce Shiga toxin 2 with fluoroquinolones, β-lactams, TMP-SMX, and metronidazole in patients of all ages should be avoided because of evidence of harm 1.

Key considerations in managing this patient include:

• Monitoring for signs of dehydration and ensuring adequate hydration
• Observing for the development of severe symptoms that may necessitate a change in management
• Avoiding unnecessary antibiotic use to prevent resistance and potential harm
• Considering the possibility of contaminated food exposure or normal colonization, especially with certain E. coli strains. Given the current evidence and guidelines, a conservative, supportive care approach is recommended, reserving antibiotics for specific, high-risk situations or severe disease manifestations 1.

From the Research

Treatment Approach

• The treatment approach for a stool culture positive for Salmonella and E. coli in an 11-year-old healthy male is not directly addressed in the provided studies.
• However, according to 2, standard stool culture should be performed in patients with infectious colitis, and pathogen-specific antimicrobial therapy should be initiated for all forms of infectious colitis other than STEC.
• For empiric treatment of febrile dysenteric diarrhea, invasive bacterial enteropathogens (Shigella, Salmonella, and Campylobacter) should be suspected, and adults may be treated empirically with 1000mg azithromycin in a single dose 2.
• It is essential to note that the provided studies do not specifically address the treatment of Salmonella and E. coli in an 11-year-old healthy male.

Antibiotic Resistance

• Multidrug resistance in Escherichia coli has become a worrying issue worldwide, with the most problematic mechanisms corresponding to the acquisition of genes coding for extended-spectrum β-lactamases, carbapenemases, 16S rRNA methylases, plasmid-mediated quinolone resistance (PMQR) genes, and mcr genes 3.
• The spread of carbapenemase genes has been mainly recognized in the human sector, but poorly recognized in animals, while colistin resistance in E. coli seems rather to be related to the use of colistin in veterinary medicine on a global scale 3.
• Ceftriaxone and azithromycin have become the drugs of choice for treating enteric fever caused by Nalidixic acid-resistant Salmonella (NARS) enterica, but there are reports of drug resistance to both drugs 4.

Predictors of Positive Stool Culture

• Patients with positive stool culture compared to a negative culture were found to have a younger mean age, greater number of unformed stools, and low serum bicarbonate level 5.
• Vibrio cholerae was found to be the most prevalent organism, followed by Salmonella spp, Campylobacter spp, and Shigella spp 5.
• Careful selection of patients based on their clinical presentation and initial laboratory workup can help decide ordering of stool culture in adults with diarrhea 5.