Salmonella enterica species (S. typhimurium and S. enteriditis serotypes) Agent Information Sheet

Boston University
Research Occupational Health Program (ROHP)
617-358-7647

Agent

Salmonella serotypes of family Enterobacteriaceae are gram negative rods; motile, aerobic and facultatively anaerobic; serological identification of somatic, flagellar and Vi antigens. They are organized into two species S. enterica and S. bongori.  S enterica serotypes S. typhimurium and enteriditis are serotypes most frequent in the US.  It is one of the non-typhoid strains of salmonella common in the US.  There are more than 2500 antigenically distinct serotypes.

Disease/Infection

The following diseases can be associated with Salmonella enterica serotypes; Typhoid like fever, Enteric fever, Typhus abdominalis.

Pathogenicity

Salmonellosis is an acute gastroenteritis; deaths are uncommon except in very young or very old or debilitated/immunocompromised. Morbidity may be high; 48 reported laboratory infections have been reported with Salmonella spp.

• Special Populations at Risk
  Higher incidence rate for infants and young children. Large reported outbreaks in hospitals, institutions, nursing homes, and restaurants.

Biosafety Information

Risk Group/BSL
Risk Group 2
Biosafety Level 2

Modes of Transmission

Host Range/Reservoir
Humans, patients with acute illness and chronic carriers, flies possibly as a vector

Symptoms
Acute infectious disease with sudden onset of abdominal pain, diarrhea, nausea and vomiting; dehydration may be severe in infants and elderly; common enterocolitis may result without enteric fever; characterized by headache, abdominal pain, nausea, vomiting, diarrhea, dehydration may result; case fatality of 16% reduced to 1% with antibiotic therapy; mild and atypical infections occur.

Generalized systemic enteric fever, headache, malaise, anorexia, enlarged spleen, and constipation followed by more severe abdominal symptoms; rose spots on trunk in 25% of Caucasian patients; complications include ulceration of Peyer’s patches in ileum, can produce hemorrhage or perforation; Food borne disease may progress to more serious septicemia, includes focal infections, abscesses, endocarditis, pneumonia; some cases develop reactive arthritis (Reiter’s syndrome) which may become chronic.

Incubation Period
The incubation period for the infection depends on size of infecting dose; usually 6 to 72 hours for gastroenteritis and 5-21 days for enteric fever.

Viability
Susceptible to many disinfectants – 1% sodium hypochlorite, 70% ethanol, 2% glutaraldehyde, iodines, phenolics, formaldehyde.

Survival Outside Host
Ashes – 130 days; rabbit carcass – 17 days; dust – up to 30 days; feces – up to 62 days; linoleum floor – 10 hours; ice – 240 days; skin – 10-20 minutes.

Information for Lab Workers

Laboratory PPE

Personal protective equipment includes but is not limited to laboratory coats or gowns, disposable gloves, and safety glasses. Face shields may be recommended based on risk assessment.

Containment

Research should be conducted using Biosafety Level 2 practices, equipment, and facility design. ABSL-2 facilities, practices and equipment are recommended for activities with experimentally infected animals. ABSL-3 conditions may be considered for protocols involving aerosols.

In Case of Exposure/Disease

• For injuries in the lab which are major medical emergencies (heart attacks, seizures, etc…):
  • Medical Campus: call or have a coworker call the Control Center at 617-414–4144.
  • Charles River Campus: call or have a coworker call campus security at 617-353-2121.
    You will be referred to or transported to the appropriate health care location by the emergency response team.
• For lab exposures (needle sticks, bite, cut, scratch, splash, etc…) involving animals or infectious agents, or for unexplained symptoms or illness call the ROHP 24/7 hour number (1-617-358-ROHP (7647); or, 8-ROHP (7647) if calling from an on-campus location) to be connected with the BU Research Occupational Health Program (ROHP) medical officer. ROHP will refer you to the appropriate health care location.
• Under any of these scenarios, always inform the physician of your work in the laboratory and the agent(s) that you work with.
• Provide the wallet-size agent ID card to the physician.

Vaccination

Two types of vaccines against typhoid fever are available in the U.S. However, vaccine does not currently exist for non typhoidal salmonella strains.

Information for First Responders/Medical Personnel

Public Health Issues

Transmission is person-to-person, by contaminated food or water, or by food contaminated by hands of carriers. Standard precautions should be utilized in general but contact precautions should be used in incontinent or diapered patients.

Diagnosis/Surveillance

Monitor for symptoms culture of stool or blood

First Aid/Post Exposure Prophylaxis

Perform one of the following actions:

Post exposure prophylaxis antibiotic should be considered.

Treatment

In immunocompetent patients, disease may be self-limited. However severe disease or in immunocompromised patients, empiric antibiotic therapy should be used; appropriate antibiotic can be based on drug susceptibility testing. fluoroquinolone, trimethoprim-sulfamethoxazole, or azithromycin or ceftriaxone can be used.

References

Public Health Agency of Canada; http://www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/salmonella-ent-eng.php

CDC BMBL:  https://www.cdc.gov/labs/pdf/CDC-BiosafetyMicrobiologicalBiomedicalLaboratories-2020-P.pdf

Mandell, G. L., J. E. Bennett, et al. (2010). Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. Philadelphia, PA, Churchill Livingstone/Elsevier.

Revised: 12/2/20