Lecture 25 Biological Hazards II- Campylobacter spp & Listeria spp Flashcards
What are the top 5 pathogens contributing to domestically acquired foodborne illnesses?
- Noroviruses
- Salmonella, nontyphoidal
- Clostridium perfringens
- Campylobacter spp.
- Staphylococcus aureus
What are the top 5 pathogens that contribute to domestically acquired foodborne illnesses resulting in HOSPITALIZATION?
- Salmonella, nontyphoidal
- Norovirus
- Campylobacter spp.
- Toxoplasma gondii
- E. coli O157
What are the top 5 pathogens contributing to domestically acquired foodborne illnesses resulting in DEATH?
- Salmonella, nontyphoidal
- Toxoplasma gondii
- Listeria monocytogenes
- Norovirus
- Campylobacter spp.
What is Campylobacter jejuni?
- Non-spore forming, G-ve rod with curved- to Sshaped morphology
- Many strains display motility (cock screw)
- 7 organisms in genus, almost all human illness is
caused by 2 organsims: - C. jejuni- common ~90% (occasionally invasive)
- C. coli- uncommon
- Worldwide distribution
Mortality in campylobacteriosis is seen mainly in:
immunocompromised
Rarely among otherwise healthy people
Who is most likely to get campylobacteriosis?
- Children < 5 and people 15-29 years (mainly
males) old more likely to get infection than
are others
a. Highest rate infants 6 -12 months old - People with weak immune systems
a. Individuals with HIV/AIDS get infected 40 times more
often - Rarely, babies can be infected in utero, causing miscarriages or stillbirths
Where is campylobacteriosis most commonly found?
Commonly found in GI tract of wild and domestic ruminants, swine, dogs, cats, fowl and rodents
This is a infection source of campylobacteriosis?
Surface water may be infection source due to fecal runoff or contamination by birds
Why are birds more likely to have higher infection rates of campylobacter?
Due to higher body temperature, infection rates can be
90-100% in birds (prefers 107.5ºF)
Poultry operations have been associated with what in terms of campylobacter?
- Resistance to antibiotics has been associated with use in
poultry operations. - Use of fluoroquinolones was removed over concerns
of resistance transfer to humans
Campylobacter sources of infection include:
- Normal gut microflora of food-producing animals
- Food Sources
a. Improperly handled or undercooked poultry
b. Raw milk and cheeses from unpasteurized milk
c. Contaminated water - Contaminated poultry carcass carries 100-100,000
Campylobacter cells
a. only 500 needed to cause infection
What are some causes of food or water contaminations of campylobacter?
- Campylobacter spreads from bird to bird through common water source or contact with infected feces
- Campylobacter can transfer to meat at slaughter
- In 2005, Campylobacter present on 47% of raw chicken breasts tested through FDA Retail Food program
Chicken flocks infected with campylobacter will show..
no signs of illness
What are some causes of food or water contamination that lead to infection of campylobacter?
- Milk can become contaminated if the cow has an udder
infection with Campylobacter or the milk is contaminated with manure - Surface water and mountain streams can become
contaminated from feces of cows or wild birds - Travelers to developing countries are also at risk of acquiring Campylobacter infection
As little as (blank) campylobacter cells can cause disease.
500
What is the incubation period and duration of campylobacteriosis?
- Incubation period - 2 to 5 days
- Duration - 2 to 10 days
Most cases of campylobacteriosis are…
self-limiting
What are the clinical signs of campylobacteriosis?
- Major signs: Fever, diarrhea, abdominal cramps, and vomiting
- Other symptoms often include abdominal pain, nausea, headache, and muscle pain
What are some complications of campylobacteriosis?
- Include bacteremia and infection of various organ systems, such as
meningitis, hepatitis, cholecystitis, and pancreatitis
a. ~ 1.5 cases of bacteremia occur per 1,000 cases - Autoimmune disorders are a potential long-term complication;
Guillain-Barré syndrome (GBS).
a. ~ 1 case of GBS per 2,000 cases, typically 2 to 3 weeks post infection
b. Antigens present on C. jejuni similar to those in nervous tissues in humans, leading to the autoimmune reaction.
How do you diagnose campylobacteriosis?
- Isolation and growth requires special incubation
conditions since the organism is microaerophilic - Fecal samples inoculated directly onto selective
media, or enriched to increase recovery - To limit growth of competing organisms, media used for
cultivation usually are supplemented with blood and
antimicrobial agents - Isolation from food is difficult, because the bacteria are
usually present in very low numbers.
How do you properly prevent infection of campylobacteriosis?
Wash hands with soap:
- before preparing food
- after handling raw foods of animal origin
- after contact with animals (particularly kittens
and puppies)
- carefully and frequently (individuals with diarrhea)
Prevent cross contamination (separate)
Do NOT drink unpasteurized milk or untreated surface water
Cook poultry to 165 F
What is Listeria monocytogenes?
- G+, rod-shaped, facultative
- 13 serotypes
Listeria monocytogenes is considered a?
Reportable disease
Listeria monocytogenes is considered an?
Important cause of death from foodborne illness
Describe listeria monocytogene in the environment.
- Ubiquitous in environment and can be found in moist environments, soil, and decaying vegetation
- Persistent in food-manufacturing environments
- Can grow at refrigeration temperatures
- ~3°C/37.4°F
- Salt-tolerant
What is the reservoir of Listeria?
Domestic and wild mammals, birds, and man
Where can you find listeria?
- May be free living (not only able to survive but to grow) in water, mud, silage and other crops, and sewage.
How long can listeria survive?
Can survive months to years in soil
What is one way Listeria can be spread?
- Widely distributed by farming techniques and spreading of manure
- Can contaminate vegetables, animal feed or water and may be transmitted to people and animals.
What are the two forms of listeriosis?
- Non-invasive GI illness
- More serious invasive form
Describe the non-invasive GI illness of listeria.
- Fever, muscle aches,
and nausea or
diarrhea - Often self-limiting in
healthy people
Describe the invasive form of listeria.
- May cause septicemia
and meningitis - Pregnant women
more susceptible to
infection, and
although they
generally recover,
their babies usually
don’t survive
What is the mortality rate of listeria?
- Severe form- case-fatality rate 15% - 30%
- with meningitis, case-fatality rate up to 70%
- with septicemia, 50%
- in perinatal/neonatal infections, more than 80%
What is the incubation period of listeria?
- Infective dose varies with the strain and susceptibility of the host, and the food matrix involved
- Gastroenteritis form: 9-48 hrs
- Severe, invasive form: 2-6 weeks
What are some common food sources of listeria?
- Raw milk
- Raw, smoked fish and other seafood
- Meat, including deli meats
- Cheeses, especially soft cheeses
- Ice cream
- Raw vegetables and fruits
Why is listeria a problem in the food industry?
It can grow in refrigerated temperatures
How is listeria diagnosed and treated?
- Culture from tissue, blood, cerebrospinal fluid, or another normally sterile site (e.g., placenta or fetus) needed for diagnosis
- Stool cultures not helpful, since some healthy humans may be intestinal
carriers - Methods of analyzing foods complex and time-consuming (5 to 7 days)
- Treatment consists of antimicrobial therapy
- Ampicillin, with or without gentamicin (both will cross the blood brain barrier)
How do you control/prevent listeria?
Do NOT drink raw milk or cheeses made with raw milk
