Exam 4 Flashcards
What caused the wedding campylobacter outbreak?
undercooked chicken liver pate
Outbreak of Campylobacter jejuni infections associated with drinking unpasteurized milk procured through a ______________.
cow-leasing program
1978 to 2014 a total of 504 outbreaks, resulting in 57,221 cases. Contaminated __________ and __________ were responsible for half of these outbreaks.
water and unpasteurized milk
What species are the most frequently involved in campylobacter outbreaks?
C. coli and C. jejuni
What does campylobacteraceae consist of?
Campylobacter and Arcobacter
What are characteristics of campylobacter?
Spiral
Gram negative
Non-spore forming may be coccoid
Microaerophilic
True or False. Campylobacter is motile.
True
_____________ practices are recommended to prevent
Campylobacter infections
Basic food hygiene
Campylobacter is _______________. It is
the most common bacterial cause of human gastroenteritis in the
world
1 of 4 key global causes of diarrheal diseases
How do people get campylobacter infections?
By eating raw or undercooked poultry or eating something that touched it. They can also get it from eating other foods, including seafood, meat and produce.
Describe the environmental susceptibility of Campylobacter.
It is sensitive to drying, low pH, high oxygen levels, and does not grow below 30°C
True or False. Campylobacter can survive well in feces, milk, water, urine. In water enter VBNC state.
True
What are reservoirs of campylobacter?
Poultry, rabbits, rodent, wild birds, sheep, horses, cows, pigs, fish, and contaminated vegetables
As the Campylobacter does not grow below 30°C, _________________________ due to consumption of improperly heat treated or
handled products. Primarily poultry.
their cases peaks during summer
What are the common reservoirs of C. coli?
pigs and birds
What are the common reservoirs of C. jejuni?
Humans, other mammals and birds
What are the main causes of campylobacter cases?
Raw milk
Food not cooked at proper temperatures
petting zoos
What are symptoms of campylobacter?
Self-limiting diarrhea, cramps, fever, and vomiting, diarrhea may be
bloody. Re-occurring abdominal pain common.
What is Guillain barre syndrome?
A rare, autoimmune disorder in which a person’s own immune system damages the nerves, causing muscle weakness and sometimes paralysis.
True or False. Its difficult to differentiate between C. Jejuni and C. coli using biochemical or culture-based methods.
True
True or False. Campylobacter enterotoxin are related to
the heat-labile enterotoxins of E. coli.
True
True or False. Adults can develop immunity. People raised on farm or people
consuming raw dairy products have higher tolerance to Campylobacter.
True
When adults develop an immunity you have protection against illness but not against _______________.
Colonization
Which Campylobacter species are most commonly associated with foodborne outbreaks?
Campylobacter jejuni and Campylobacter coli
What are the optimal microaerophilic conditions for Campylobacter growth?
5% oxygen, 10% carbon dioxide, and 85% nitrogen
Why is Campylobacter significant globally?
It is one of the four key global causes of diarrheal diseases and the most common bacterial cause of gastroenteritis.
What are typical symptoms of campylobacteriosis?
Diarrhea (often bloody), abdominal pain, fever, and vomiting with symptoms lasting 2-10 days
How do flagella contribute to Campylobacter virulence?
Flagella allow motility and adhesion to epithelial cells, essential for colonization
What is a major cause of epidemic diarrheas throughout the developing world?
Cholera
What areas continue to report the vast majority of cholera cases?
Resource-poor areas
What is an intestinal infection caused by toxigenic vibrio cholerae, group O-1 or O-139?
Cholera
Describe the characteristics of vibrio.
Gram-negative
Asporogenous rods
Motile
True or False. Most members of the vibrio genus produce catalase.
True
True or False. Members for the vibrio genus ferment glucose without producing gas.
True
How many species of vibrio are there?
80
How many vibrio species are known human pathogens?
12
How many vibrio species are directly associated with food?
8
Vibrio are predominant bacterial genus in ___________ and are associated with a variety of seafood.
estuarine water
______ are predominant bacterial genus in estuarine water and are associated with a variety of seafood.
Vibrio
_______ causes cholera.
V. cholerae O1
Pathogenic strains produce _____________.
cholera enterotoxin
What are other virulence factors of cholerae?
Colonization factors
Flagella
LPS
Polysaccharide capsule
What is the mechanism of vibrio cholerae?
- ingestion of contaminated food or water
- Pass through acid barrier of stomach and colonize in small intestine
- Produce adherence factor
- Production of CT toxin
- Disrupt ion transports by intestinal epithelial cells, which leads to sever diarrhea
What is an endemic?
a disease that exists permanently in a particular region or population. Malaria is a constant worry in parts ofAfrica.
What is an epidemic?
An outbreak of disease that attacks many peoples at about the same time and may spread through one or several communities
What is a pandemic??
When an epidemic spreads throughout the world.
What is a characteristic of vibrio cholerae (disease)?
explosive, dehydrating diarrhea
“rice-water stools” is associated with what infection?
Vibrio cholerae
What are reservoirs of vibrio cholerae?
- Free-living bacterial flora estuarine
- Non-O1 and non-O139
- Shellfish
True or False. Vibrio can enter in VBNC state in water and can become active after ingestion and cause disease.
True
Vibrio are ________________ and food acts as buffer and increase pathogen survival.
sensitive to acidic pH
True or False. Consumption of raw seafood can lead to vibrio infection.
True
Vibrio infection __________ be controlled through shellfish sanitation program. Therefore, seafood must be refrigerated.
CANNOT
What is a federal/state cooperative program recognized by the FDA and the interstate shellfish sanitation conference?
NSSP (National Shellfish Sanitation Program)
What is the goal of NSSP?
maintain sanitary control of shellfish produced and sold for human consumption
Participants in the NSSP include agencies from shellfish producing and non-producing States to the ____________________ and the shellfish industry.
FDA, EPA, NOAA
True or False. Vibrio is sensitive to the cold.
True
What is the growth medium for vibrio?
Alkaline peptone water (enrichment broth)
TCBS agar (plating media)
What is an isolation and identification technique of vibrio?
Nucleic acid-based methods
What targets the species-specific vibrio genes in combination with CT-producing (ctx) genes?
Nucleic acid-based methods
What are the 5 steps for preventing cholera?
- Drink and use safe water
- Wash hand often with soap and water
- Use latrines, do not defecate in any body of water
- Cook food well
- Clean up safely
_______ recently approved a single-dose live oral cholera vaccine called Vaxchora.
FDA
What strain of vibrio posses the ability to produce hemolysin?
Vibrio parahaemolyticus
What are examples of hemolysin?
TDH or kanagawa hemolysin
What are reserviors of vibrio parahaemolyticus?
-Estuarine water
-Easily isolated from costal water
-Sediments, suspended particle, plankton
-Fish and shellfish
-Clam, oyster, lobster, scallops, shrimps, crabs
True or False. Jan-Feb seafood are free of V. parahaemolyticus
True
V. parahaemolyticus outbreaks are exclusively associated with what food?
Seafood
What are disease characteristics that are associated with V. parahaemolyticus?
Symptoms: Diarrhea, abdominal cramps, nausea, fever
sunshine and _____________ promote vibrio growth in sea water, increasing chances of infection
warm water
True or False. Low level of V. parahaemolyticus can quickly multiply and reach infective dose, if the product is not refrigerated.
True
V. vulnificus is a ……
flesh eating bacterium
What is the leading cause of reported deaths due to foodborne illness in florida?
V. vulnificus
What is the susceptibility of V. vulnificus?
It is susceptible to freezing, low temp, pasteurization, HHP and ionizing radiation
What pathogen is not associated with presence of fecal coliforms?
V. vulnificus
What is depuration?
A process by which shellfish are held in tanks of clean seawater under conditions which maximize the natural filtering activity
What are three functions of microbes in food?
- Production of food: yogurt, wine
- Spoilage of raw/processed food
- Human illness
What provides an estimation of number of aerobic microbes that can grow at 35±2°C
Aerobic plate count (APC)
Why do we hear more about outbreaks associated with ground beef and not with steak?
Food can get contaminated
at different steps of processing (handling, grinding, packaging), bacteria can multiple (time of processing), variation in quality of ingredients.
What are two manuals or guidebooks used in sample collection?
FDA Bacterial Analytical Manual
USDA Microbiologist Laboratory Guidebook
How should sample collections be collected?
Using aseptic technique
What are the disadvantages of spread plates?
Coalescence of colonies
Spiral plater is used for
milk and food
What is an AOAC approved method?
spiral plater
What is an advantage of a spiral plater?
Use of less agar, less plates and less dilution bottle, AOAC approved
What are disadvantages of spiral plater?
Useful for liquid samples, difficulty in counting colonies as they are tightly packed.
What is membrane filtration useful for?
liquid samples that have a low bacterial population
What are advantages of membrane filtration?
- Large volume of liquid samples can be concentrated
- Large volume of air samples can be concentrated
- Used for viscous samples such as milk and juice
- Used for water sample with low number of bacteria
What is the fastest method as no incubation is required?
DMC
What are advantages of DMC?
Little processing of samples and limited equipment
What are disadvantages of DMC?
Detection of dead and live cells
What test is an example o surface testing?
Swab test
What can be used to label live and dead cells?
Fluorescent dyes
What can be used to identify and characterize bacteria?
Microbial metabolism
The rate at which the dye color changes is ________ proportional to the number of bacteria in sample.
directly
Culture-based method are great, but _____________ for final
conformation.
they take a long time
What is a diverse group of fungi characterized by their filamentous structure and ability to form spores?
Molds
What is a long, thread-like structures that form the fungal body?
Hyphae
What is a network of hyphae visible to the naked eye?
Mycelium
What are reproductive structures that allow molds to disperse and colonize new environments?
Spores
What is known for rapid growth?
Zygomycota
What is the temperature range of mold growth?
10°C and 40°C
What are the beneficial roles of molds?
Fermentation
organic acid production
Bioactive metabolites
Antibiotics
What produces aflatoxins?
Aspergillus
What food are affected by aflatoxins?
Grains, nuts and milk
Aflatoxins are _____________ and cannot be destroyed by cooking or pasteurization.
heat-stable
Aflatoxin M1 is found in
the milk of animals
What is the target organ for aflatoxin?
Liver
What can lead to the stunted growth and malnutrition in children?
AFGI
What is the mechanism of Aflatoxins?
- Generation of reactive oxygen species
- Target mitochondria
- Target Red blood cells
What are ochratoxins affected foods?
Cereal, beverage, and dried fruits
Ochratoxins toxin effect
Kidney toxicity
Carcinogenicity
Immunosuppression
What is the mechanism of ochratoxins?
Generate ROS
Lipid peroxidations
DNA Damage
Protein oxidation
What myotoxins does mycotoxins produce?
Patulin and citrinin
What is found in apples and apple-based products?
Patulin
What is found in stored grains; nephrotoxic and linked to kidney damage?
Citrinin
What mold grows within the cheese?
Penicillium roqueforti
What is the limit for aflatoxins in food?
50 ppb
What are the target organs for patulin?
GI tract
Citrinins are ____________ and cannot be destroyed by cooking or pasteurization.
heat-stable
What is the mechanism of action of citrinin?
Nephrotoxcitiy and membrane potential depolarization
