Poster 9: Listeria

Question 1

Pathogen

Answer 1

• listeria monocytogenes
• facultative anaerobic gram+ bacteria
• mostly prevalent are GI tract symptoms
• 25-30% mortality in compromised hosts
• bacteria may infect host’s brain, spinal cord and blood stream through ingesting of contaminated food
• does not form pores but capable of growing at 0C

Question 2

Symptoms

Answer 2

• septicemia
• meningitis
• encephalitis

Question 3

Treatment options

Answer 3

• antibiotics
• food additive such as bacteriophage P100
• UV light

Question 4

Mechanism of action

Answer 4

• enters villi of intestinal epithelium and replicates in the lamina propria
• using protein interalin, it translocated across barriers to target the liver, spleen and lymph nodes
• enters professional phagocytes via endocytosis
• escapes vacuole using listeriolysin O
• infected phagocytes can circulate, or pathogen escapes and is mobile through intracellular space
• virulence factor ActA moves bacteria between cells through actin polymerization

Question 5

The Dairy industry

Answer 5

• up to 46% of cases linked to dairy products
• increased handling and fecal shedding present additional risks to water and silage, udders or teat canals, milking environment, equipment, and workers