What is the diagnosis and treatment for Salmonella-induced gastroenteritis?

From the Guidelines

Salmonella gastroenteritis is a common bacterial infection of the intestinal tract that typically resolves without antibiotics in 4-7 days, and treatment should focus on preventing dehydration and promoting recovery, rather than relying on antibiotics, which may prolong bacterial shedding, as recommended by the 2017 Infectious Diseases Society of America clinical practice guidelines 1.

Key Considerations

• For most healthy adults, treatment focuses on preventing dehydration through oral rehydration with water, clear broths, and electrolyte solutions like Pedialyte or sports drinks.
• Antibiotics are generally not recommended for uncomplicated cases as they may prolong bacterial shedding, but are indicated for severe cases, immunocompromised patients, adults over 65, infants under 3 months, or those with invasive disease.
• When needed, ciprofloxacin (500mg twice daily for 3-5 days) or azithromycin (500mg daily for 3 days) are commonly prescribed, as suggested by the guidelines 1.

Prevention and Management

• While experiencing symptoms, patients should avoid preparing food for others, practice good hand hygiene, and stay hydrated.
• Anti-diarrheal medications like loperamide should be avoided as they can prolong the infection.
• Salmonella spreads through contaminated food or water, particularly undercooked poultry, eggs, and unpasteurized dairy products.
• Prevention includes thorough cooking of animal products, avoiding cross-contamination in the kitchen, and proper handwashing after handling raw foods or contact with animals, especially reptiles, as emphasized by the guidelines 1.

Special Considerations

• Asymptomatic people who practice hand hygiene and live and work in low-risk settings do not need treatment, except asymptomatic people with Salmonella enterica subspecies enterica serovar Typhi in their stool who may be treated empirically to reduce potential for transmission, as recommended by the guidelines 1.
• Asymptomatic people who practice hand hygiene and live and work in high-risk settings should be treated according to local public health guidance, as suggested by the guidelines 1.

From the FDA Drug Label

Infectious Diarrhea caused by Escherichia coli (enterotoxigenic strains), Campylobacter jejuni, Shigella boydii†, Shigella dysenteriae, Shigella flexneri or Shigella sonnei† when antibacterial therapy is indicated. Typhoid Fever (Enteric Fever) caused by Salmonella typhi.

The drug ciprofloxacin is indicated for the treatment of Typhoid Fever caused by Salmonella typhi, but it does not explicitly mention Salmonella gastroenteritis. However, Salmonella species can cause gastroenteritis, and ciprofloxacin may be effective against some strains.

• The FDA label does mention Salmonella typhi, which is a type of Salmonella.
• Ciprofloxacin may be used to treat infectious diarrhea caused by certain bacteria, including some strains of Salmonella. However, the label does not provide direct information on the use of ciprofloxacin for Salmonella gastroenteritis. Therefore, a conservative clinical decision would be to use ciprofloxacin for Salmonella gastroenteritis only if the specific strain is known to be susceptible to the drug, and other treatment options have been considered 2.

From the Research

Salmonella Gastroenteritis Treatment

• Salmonella gastroenteritis is usually a self-limiting infection and does not require treatment 3.
• However, in some immunosuppressed patients, such as the newborn, the elderly, those with AIDS or neoplasms, there is a greater risk of developing a severe systemic infection, and in these cases, antibiotic treatment is recommended 3, 4.
• Third-generation cephalosporins and fluoroquinolones are the most useful antibiotics in the treatment of these infections, although resistant strains are sometimes isolated 3, 4.

Antibiotic Resistance

• The emerging resistance to fluoroquinolones, production of extended-spectrum beta-lactamases, and the increase of multidrug resistant Salmonella strains are major problems in the search for efficient antimicrobial therapy of Salmonella infection 4.
• Azithromycin represents an alternative option to treat bacterial diarrhea when the antibiotic therapy is indicated, and it has been shown to be effective against Salmonella isolates 5.
• However, the response to treatment with azithromycin may be sub-optimal in some patient groups when compared with fluoroquinolones, and it is associated with delayed treatment response and prolonged bacteraemia 6.

Treatment Outcomes

• There is no evidence of a clinical benefit of antibiotic therapy in otherwise healthy children and adults with non-severe salmonella diarrhoea 7.
• Antibiotics appear to increase adverse effects and they also tend to prolong salmonella detection in stools 7.
• Azithromycin at a dose of 500mg daily is an effective treatment for fully sensitive strains of S. Typhi but is associated with delayed treatment response and prolonged bacteraemia when compared with ciprofloxacin 6.