FOODBORNE INFECTIONS continued

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FOOD-BORNE INFECTIONScontinued

• Yersinia enterocolitica, Listeria monocytogenes

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Yersinia enterocolitica

• Yersiniosis
• The organism small G-ve rods of family
  Enterobacteriaceae
• Geographical variation in pathogenic serotypes
• Serotype O3 in NZ

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Yersinia enterocolitica

• Characteristics
• - grows at wide range of temperatures
• (0 to 44 0 C), aerobically
  anaerobically
• - withstands freezing survives in damp
• soil

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Yersinia enterocolitica

• CCPs hurdles
• - pasteurization destroys
• - presevatives (nitrites, herb spice
• extracts) slow
  down
• - somewhat resistant to chlorine
• - UV radiation kills (water treatment)

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Yersinia enterocolitica

• Pathogenesis
• - adheres penetrates terminal
• ileum epithelial cells
• - invades intestinal mucosa
• - multiplies in lymphoid tissue

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Yersinia enterocolitica

• The illness
• - incubation 7 days
• - abdominal pain (confused with
  appendicitis)
• - headache, fever, diarrhoea, nausea
• vomiting (children watery, mucoid
  diarrhoea)

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Yersinia enterocolitica

• The illness, continued
• - infective dose unknown
• - children lt 4 years adults 20-34 years
• - Rx antibiotics when serious

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Yersinia enterocolitica

• Sources
• - human person-to-person, hospitals
• - animal primary source is pigs (tongue
  
• tonsils), companion
  animals, rats
• insects
• - food pork pork products
• - environment drinking surface water,
• sewage sludge
  

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Yersinia enterocolitica

• Outbreaks/incidents
• NZ
• case-control study done in Auckland
• (care of young child, town water
  reticulated
• sewerage protective consumption
• of pork sandwiches from sandwich
  bar
• linked to cases)
  
• Overseas
• - dairy products mainly

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Yersinia enterocolitica
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Listeria monocytogenes

• Listeriosis
• (invasive disease non-invasive enteritis)
• The organism Gve ovoid to rod-shaped bacterium
• Widespread in environment

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Listeria monocytogenes

• Characteristics
• - grows in wide range of temperatures (1 to
  45o C)
• - survives freezing
• - aerobic anaerobic
• conditions

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Listeria monocytogenes

• CCPs hurdles
• - higher temperatures, low pH, a
• number of preservatives
• - disinfectants (alcohols, phenols
• QACs)
• - UV radiation

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Listeria monocytogenes

• Pathogenesis
• - bacterium crosses intestinal epithelial
  cells M cells in Peyers patches via phagosomes
• - released into cytoplasm multiplies
• - invades next cell, propelled by actin tail
• - phagosomes transported via blood vessels to
  lymph nodes, liver, spleen, brain placenta

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Listeria monocytogenes

• The illness invasive form
• - incubation 30 days
• - flu-like symptoms, diarrhoea,
• vomiting, meningitis, septicaemia,
• spontaneous abortion

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Listeria monocytogenes

• The illness invasive form, continued
• - infective dose 100 to 1 000 cells
• - pregnant women, newborn babies, the elderly
  AIDS patients
• - Rx penicillin, ampicillin /- gentamicin
  

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Listeria monocytogenes

• The illness non-invasive
• - incubation 18 hours
• - diarrhoea, fever, muscle pain,
• headache, abdominal cramps
• vomiting

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Listeria monocytogenes

• The illness non-invasive
• - infective dose gt 100 thou. cells/gm
• - all individuals susceptible
• - Rx - penicillin, ampicillin /-
• gentamicin

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Listeria monocytogenes

• Sources
• - human person-to-person rare
• - animal diseased animals shed in faeces,
  
• contamination of red
  meat silage
• - food ready-to-eat cooked food with long
• shelf-life
• - raw foods
• - environment widespread in soil, water
  sewage
• (Hospitals occupational
  exposure)

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Listeria monocytogenes

• Outbreaks/incidents
• NZ
• unpasteurized milk, uncooked hotdogs,
• undercooked chicken, soft cheeses,
• delicatessen counter foods

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Listeria monocytogenes
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Listeria monocytogenes

• Outbreaks/incidents
• Overseas
• invasive coleslaw, Mexican-style
• fresh cheese, pork
  tongue
• - non-invasive corn salad, cold
• smoked trout,
• chocolate milk