Morphology   Gram positive, aerobic, mobile, intracellular coccobacilli that may form chains.
Growth Conditions Growth at 4°C
Health Hazards
Host Range Mammals, fish, birds, crustaceans, and insects. Pregnant women, the elderly, immunocompromised, fetuses, and neonates are the most at risk for listeriosis.
Modes of Transmission  Ingestion of contaminated food, direct contact with contaminated soil, and transmission from the mother to fetus during birth. Infected mothers may shed for 7- 10 days after delivery.
Signs and Symptoms  Symptoms of listeriosis include fever, muscle ache, nausea, and diarrhea may occur. Infection may spread to the nervous system causing meningitis. Endocarditis, septicemia, and disseminated granulomatous may occur in infected adults. Pregnant women may experience only a mild, flu-like illness. However, infections during pregnancy can lead to abortion, stillbirth, premature delivery, or infection of the newborn.
Infectious Dose Unknown
Incubation Period  From 3-70 days. Median incubation period is 21 days.
Medical Precautions/Treatment
Prophylaxis None available. 
Vaccines None available.
Treatment Antibiotic therapy (penicillin or ampicillin alone or with aminoglycosides). Resistant to cephalosporins.
Surveillance Monitor for symptoms. Test feces, CFS, or blood.
MSU Requirements  Report any exposures
Laboratory Hazards
Laboratory Acquired Infections (LAIs) There have only been 2 reported LAIs. Pregnant women should take special caution to avoid contact with infected material.
 Sources Cerebrospinal fluid, blood, placental/fetal tissue, genital track secretions, amniotic fluid, and infected animals.
Supplemental References
BMBL:5th Edition
Canadian MSDS
Containment Requirements
BSL2 For all procedures involving known or potentially infected cultures.
ABSL2 For all procedures utilizing infected animals.
Spill Procedures
Small Notify others working in the lab. Remove and don new PPE. Cover area of the spill with absorbent material and add 10 % Bleach. Allow 30 minutes hour of contact time. After 30 minutes and then cleanup and dispose of materials.
For assistance, contact MSU's Biosafety Officer: Ryan Bartlett,, (406) 994-6733
or Safety and Risk Management (406-994- 2711).
Exposure Procedures
Mucous membrane
Flush eyes, mouth or nose for 5 minutes at eyewash station.
Other Exposures
Wash area with soap and water for 5 minutes.
Immediately report incident to supervisor, complete a first report of injury report, and submit to Safety and Risk Management.
Medical Follow-up
During business hours: Bridger Occupational Health 3406 Laramie Drive. Weekdays 8am -6pm.  Weekends 9am-5pm
After business hours: Bozeman Deaconess Hospital Emergency Room 915 Highland Blvd Bozeman, MT
Disinfection Susceptible to 10 % Bleach, 70 % ethanol, and glutaraldehyde.
Inactivation Inactivated by moist heat (15 minutes at 121° C), dry heat (1 hour at 160-170° C), short wave UV, and gamma irradiation.
Survival Outside Host Able to survive outside of hosts (water, soil, food, feces). Capable of growing at low temperatures (-4 to 0-0.1° C)
Personal Protective Equipment (PPE)
Minimum PPE Requirements At minimum, gloves, closed toed shoes, lab coat, and appropriate face and eye protection prior to working with L. monocytogenes. Additional PPE may be required depending on lab specific SOPs
Additional Precautions None required