Salmonella enterica spp. Biological Agent Reference Sheet (BARS)

Updated November 30th, 2023

Summary

Agent Characteristics 

Risk Group: RG-2 associated with human disease, rarely serious; preventive or therapeutic interventions often available.

Agent Type: Bacteria 

Description: Salmonella enterica is one of two Salmonella species and is a member of the Enterobacteriaceae family. It is a gram-negative facultative anaerobe, and has motile non-sporing rods that are 0.7-1.5 by 2.0-5.0 µm in size. All species of Salmonella can infect humans. Symptoms manifest as gastroenteritis, bacteremia, and/or enteric fever. It is also possible for infection to exist in an asymptomatic carrier state. Infection is most common in children under the age of five, adults 20-30 years old, and patients 70 years or older. Salmonella enterica subspecies enterica has 2610 different serovars, the most well known being serovars Typhi, Paratyphi, Enteriditis, Typhimurium and Choleraesuis. The serovars are characterized by three surface antigens: the flagellar “H” antigen, the oligosaccharide “O” antigen and the polysaccharide “Vi” antigen (found in Typhi and Paratyphi serovars). Salmonella enterica is a facultative anaerobe and is a gram negative, motile and non-sporing rod that is 0.7-1.5 by 2.0-5.0 µm in size. The great majority of Salmonella serovars most commonly cause gastrointestinal disease, and are termed non-typhoidal serovars. A few serovars routinely cause more severe, systemic disease in humans; these are Typhi and Paratyphi and are termed typhoidal serovars. However, even nontyphoidal serovars can cause severe systemic disease in some cases, most commonly in immunocompromised hosts. Commonly interchanged terms include:

• Serovar Typhi - Typhoid fever, Enteric fever, Typhus abdominalis, Salmonella enterica serovar Typhi
• Serovar Choleraesuis - Salmonella septicemia, hog cholera, hog typhoid, Salmonella enterica serovar Choleraesuis, salmonellosis
• Serovar Paratyphi - Enteric fever, Paratyphoid fever, Salmonella Paratyphi type A, B and C, Salmonella enterica serovar Paratyphoid A, B and C.

Host Range: Domestic and wild animals such as cattle, swine poultry, wild birds, amphibians, reptiles, and flies; humans are usually the final host.

Host Shedding: Direct contact, Feces

Route of Exposure to Humans: Direct contact, Ingestion, Percutaneous

Infectious Dose: Varies with serotype, approximately 103-105 bacilli.

Incubation Period: Variable for non-typhoidal salmonellosis, depending on the inoculum size, ranging from 5 and 72 hours; typhoid fever has an incubation period between 3 and 60 days, with most infections occurring 7-14 days after contamination.

Health Hazards

Signs and symptoms of infection may include:

• Flu-like symptoms (i.e. fever, headache, dehydration, weight loss, lethargy)
• Gastrointestinal symptoms (i.e. loss of appetite, nausea, vomiting, diarrhea)

Immunizations:  Available                                           Prophylaxis*: None Available

*Formal medical advice is obtained during medical consultations with Cornell Health or primary healthcare provider as needed.

Agent Viability 

For more guidance on disinfection see:  disinfectant selection.

Laboratory Hazards 

• High energy-creating activities (centrifugation, sonication, high pressure systems, vortexing, tube cap popping)
• Splash/droplet-creating activities (shaking incubators, liquid culturing, mechanical pipetting)
• Equipment contamination
• Exposed skin/uncovered wounds

Laboratory Acquired Infection (LAI) History:  258 cases and 20 deaths due to laboratory-acquired typhoid fever were reported until 1974. Until 1976, 48 cases of salmonellosis were reported and between 1979 and 2004, 64 cases and 2 deaths were reported. Most of these cases were associated with S. typhi. In recent years, 41 individuals were infected with the same strains of Salmonella typhimurium since November 2013. Findings linked these cases to various clinical and university laboratories.

Laboratory Handling Guidelines 

Laboratory Biosafety Level (BSL): BSL-2

Waste Management: Regulated Medical Waste (RMW)

Shipping Guidance: Refer to EHS Biological Materials Shipping 

Animal Vivarium Guidance

Animal Housing Biosafety Level (ABSL): ABSL-2

Animal Biosecurity: Experimental animals are housed separately

Perform Inoculations: Benchtop, Biosafety Cabinet

Change Cages: Benchtop, Biosafety Cabinet

Exposure and Spill Procedures 

Mucous Membranes: Flush eyes, mouth, or nose for 15 minutes at an eyewash station. See: responding to exposures.

Other Exposures: Wash with soap and water for 15 minutes (open wounds, sores, etc.) or a minimum of 20 seconds for areas with intact skin. See:  responding to exposures.

Small Spills: Notify others working in the lab. Evacuate area and allow 30 minutes for aerosols to settle. Don appropriate PPE. Cover area of the spill with paper towels and apply disinfectant, working from the perimeter toward the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials. See: spill cleanup

Large Spills: Request assistance from the EHS Spill Team by calling CUPD dispatch. Call 911 from a campus phone or 607-255-1111 from a mobile phone.

Incident Reporting: Immediately report the incident to supervisor and complete the EHS online injury/illness report as soon as possible.

Medical Follow-Up:

• For students, seek medical attention at Cornell Health or local primary care provider. Call Cornell Health at 607-255-5155 (24-hour phone consultation line) or a local urgent care. 
• For faculty and staff, seek medical evaluation with a local primary care provider or urgent care. Cornell Health does not see employees for post-exposure care. 
• Emergencies: Call 911 from a campus phone or 607-255-1111 from a mobile phone.