Salmonella Infection

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Salmonella infection, also known as salmonellosis, is a common bacterial disease that affects the intestinal tract. Salmonella bacteria typically live in animal and human intestines and are shed through faeces.

Aetiology

Salmonella infection is caused by bacteria of the genus Salmonella. The infection is usually contracted through:

• Consumption of contaminated food or water (especially undercooked poultry, eggs, and meat)
• Contact with infected animals or their environments
• Person-to-person transmission through the faecal-oral route

Pathophysiology

The pathophysiology of Salmonella infection involves:

• Ingestion of Salmonella bacteria.
• The bacteria survive the acidic environment of the stomach and reach the intestines.
• They invade the intestinal mucosa, causing inflammation and diarrhoea.
• In severe cases, the bacteria can enter the bloodstream, leading to systemic infection.

Risk Factors

• Consumption of raw or undercooked eggs, poultry, and meat
• Drinking contaminated water
• Contact with reptiles or birds
• Poor hygiene practices
• Travelling to areas with poor sanitation
• Immunocompromised individuals

Signs and Symptoms

The signs and symptoms of Salmonella infection include:

• Diarrhoea
• Abdominal cramps
• Fever
• Nausea and vomiting
• Headache
• Muscle pain

Investigations

Specific investigations to diagnose Salmonella infection include:

• Stool culture: To isolate and identify Salmonella species.
• Blood culture: In cases of suspected systemic infection.
• Full blood count (FBC): To check for elevated white blood cell count and other markers of infection.
• Serology: Occasionally used to detect antibodies against Salmonella, but less commonly performed.

Management

Primary Care Management

• Rehydration: Oral rehydration solutions to prevent dehydration from diarrhoea.
• Antidiarrhoeal medications: Such as loperamide may be used in non-severe cases, but generally avoided to allow the infection to clear.
• Antibiotics: Typically not required for mild cases, but may be considered for severe or prolonged infections, or in immunocompromised individuals. Common antibiotics include ciprofloxacin or azithromycin.
• Hygiene advice: Emphasising hand washing and safe food handling practices to prevent spread and reinfection.

Specialist Management

• Hospitalisation: For severe cases, particularly if dehydration, sepsis, or complications arise.
• Intravenous fluids: To manage severe dehydration and maintain electrolyte balance.
• Further investigations: In cases of complications such as reactive arthritis or bacteraemia, specialist referral and further investigations may be necessary.
• Public health measures: Reporting cases to public health authorities to monitor and prevent outbreaks.

References

1. NHS (2024) Salmonella infection. Available at: https://www.nhs.uk/conditions/salmonella-infection/ (Accessed: 24 June 2024).
2. Centers for Disease Control and Prevention (2024) Salmonella (Salmonellosis). Available at: https://www.cdc.gov/salmonella/index.html (Accessed: 24 June 2024).
3. World Health Organization (2024) Salmonella. Available at: https://www.who.int/news-room/fact-sheets/detail/salmonella-(non-typhoidal) (Accessed: 24 June 2024).
4. British Medical Journal (2024) Salmonella infection: clinical features, diagnosis, and management. Available at: https://www.bmj.com/content/350/bmj.h3037 (Accessed: 24 June 2024).

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