For health professionals: Salmonellosis (Salmonella)

Find detailed information on salmonellosis for health professionals.

On this page

• What health professionals need to know about salmonellosis
• Clinical manifestations
• Diagnosis
• Treatment
• Salmonellosis surveillance in Canada
• For more information

What health professionals need to know about salmonellosis

The genus Salmonella is a member of the family Enterobacteriaceae. There are 2 species of Salmonella:

1. Salmonella enterica
2. Salmonella bongori

The Salmonella enterica species is subdivided into 6 subspecies:

1. enterica (I)
2. salamae (II)
3. arizonae (IIIa)
4. diarizonae (IIIb)
5. houtenae (IV)
6. indica (VI)

The enterica subspecies of Salmonella enterica has at least 2,610 different serotypes, and can be divided into 2 broad groups:

1. typhoidal Salmonella, which refers to the specific Salmonella serotypes that cause typhoid fever or paratyphoid fever, including:
   • typhi
   • paratyphi A
   • paratyphi B
   • paratyphi C
2. non-typhoidal Salmonella, which refers to all other serotypes

The National Enteric Surveillance Program annual report:

• lists all the serotypes reported in Canada each calendar year
• highlights those most commonly reported

Clinical manifestations

Non-typhoidal Salmonella enterica can cause 3 different clinical manifestations:

1. gastroenteritis
2. bacteremia
3. an asymptomatic carrier state

Fecal shedding of Salmonella usually continues for several days or weeks beyond the acute phase of illness. Administration of antibiotics may not decrease this length of time.

Diagnosis

Confirm diagnosis by:

• isolation or culture identification from stool or blood
• serotyping to identify the serotype

Salmonella can also be detected through a culture-independent diagnostic test (CIDT). To identify the serotype of Salmonella detected through a CIDT, a follow-up (reflex) culture is needed.

Non-typhoidal Salmonella infection

In the case of acute gastroenteritis, stool specimens should be collected and sent to a local laboratory for testing.

If non-typhoidal Salmonella bacteremia is suspected, blood cultures should be collected and sent to a laboratory for testing. Serology doesn't provide adequate information for diagnosis of infection.

Asymptomatic infections

To identify asymptomatic infections, fecal material should be inoculated into an appropriate enrichment medium. Specimen collection should be carried out over several days, as excretion of Salmonella organisms may be intermittent.

Antibiotic-resistant infections

Increasingly, some strains of Salmonella are resistant to antibiotics recommended for the treatment of Salmonella infections.

Antimicrobial susceptibility testing may not be routinely performed for Salmonella isolates.

If considering antibiotic treatment, contact your laboratory to request antimicrobial susceptibility testing if available.

If Salmonella is identified by a CIDT, request a follow-up (reflex) culture for antimicrobial susceptibility testing.

Treatment

Treatment depends on the clinical symptoms presented by the patient. Consultation may be required with an infectious disease specialist to determine the most appropriate treatment.

Gastroenteritis

The usual treatments for gastroenteritis symptoms are:

• control of nausea and vomiting
• fluid and electrolyte replacement

Antibiotic treatment is not usually used. However, it may be necessary for:

• neonates
• children
• the elderly
• the immunosuppressed

Bacteremia

Bacteremia occurs when Salmonella enters the bloodstream. Antibiotics are needed to treat bacteremia.

Asymptomatic carrier state

Treatment of asymptomatic carriers using antibiotics is generally not recommended.

Antibiotic-resistant infections

If antibiotic treatment is considered necessary, tailor the choice of antibiotic to the results of antimicrobial susceptibility testing. Consider consulting an infectious disease specialist for the management of patients with antibiotic-resistant or complicated Salmonella infections.

Salmonellosis surveillance in Canada

Salmonellosis is a nationally notifiable disease. Health professionals are to report cases to their provincial or territorial public health authorities.

Health professionals in Canada play a critical role in identifying and reporting cases of salmonellosis. See the surveillance section for more information on surveillance in Canada.