From the Guidelines
Azithromycin is the recommended first-line antibiotic regimen for bacterial gastroenteritis, particularly for cases of dysentery or acute watery diarrhea with greater than mild fever, due to its efficacy and safety profile. The decision to treat bacterial gastroenteritis with antibiotics should be based on the severity of illness and the presence of specific pathogens. According to the guidelines for the prevention and treatment of travelers' diarrhea, azithromycin has been shown to be superior to levofloxacin in achieving clinical cure in settings with high rates of fluoroquinolone-resistant Campylobacter spp. 1.
Key Considerations
- The selection of an empiric antibiotic should consider the likelihood of treatment efficacy, regional patterns of probable target pathogens and their antimicrobial resistance, safety and tolerance profile, simplicity of treatment regimen, and cost.
- Azithromycin has been demonstrated to be effective against a range of pathogens, including Shigella spp., enteroinvasive E. coli, Aeromonas spp., Plesiomonas spp., and Yersinia enterocolitica.
- Fluoroquinolones (FQs) retain efficacy in much of the developing world, but their use is limited by concerns about reduced benefit due to the likelihood of FQ-resistant Campylobacter spp. or Shigella spp. being the cause of dysentery 1.
Treatment Regimens
- Azithromycin: 1-gm single dose or 500 mg daily for 3 days.
- FQs: 500 mg daily for 3 days, but their use is not recommended as first-line therapy due to concerns about resistance.
- Rifaximin: a nonabsorbable antibiotic that has demonstrated comparable efficacy to FQs in non-invasive TD caused by diarrheagenic E. coli, but is less effective for the treatment of invasive pathogens 1.
Supportive Care
- Fluid replacement and electrolyte management remain the cornerstone of treatment for bacterial gastroenteritis.
- Antibiotics should be used judiciously, as they may prolong carrier states for some pathogens, disrupt gut microbiota, and increase the risk of hemolytic uremic syndrome in E. coli O157:H7 infections 1.
From the FDA Drug Label
The usual spectrum of antimicrobial activity of sulfamethoprim and trimethoprim includes the following bacterial pathogens ... The usual spectrum also includes enterotoxigenic strains of Escherichia coli (ETEC) causing bacterial gastroenteritis. The recommended antibiotic regimen for bacterial gastroenteritis is trimethoprim-sulfamethoxazole for enterotoxigenic strains of Escherichia coli (ETEC) 2.
- Key points:
- The drug label does not provide a comprehensive list of all possible antibiotic regimens for bacterial gastroenteritis.
- Trimethoprim-sulfamethoxazole is effective against ETEC, a common cause of bacterial gastroenteritis.
From the Research
Recommended Antibiotic Regimens
The recommended antibiotic regimens for bacterial gastroenteritis vary depending on the causative pathogen and the severity of the illness.
- For infections due to Shigella and Campylobacter, azithromycin is the preferred antibiotic 3, 4, 5, 6.
- For salmonellosis, ceftriaxone and ciprofloxacin are recommended when antibiotic treatment is indicated 3.
- For acute watery diarrhea, azithromycin, levofloxacin, and ciprofloxacin are options, with azithromycin being the preferred first-line antibiotic 4.
- Rifaximin is another alternative for acute watery diarrhea, but it should not be used with invasive illness 4.
- The use of loperamide in combination with antibiotic treatment can be beneficial in reducing gastrointestinal symptoms and duration of illness 4.
Considerations for Antibiotic Choice
The choice of antibiotic should take into account the travel destination and regional differences in the predominance of pathogens and resistance levels 4.
- Fluoroquinolones, such as ciprofloxacin, are becoming less effective due to increasing resistance, particularly among Campylobacter spp. 4, 7.
- Azithromycin may be a good empirical therapeutic option for the treatment of bacterial enteritis, especially for infections caused by pathogens other than Campylobacter 5.