Pathogens Flashcards
A patient comes in 5 days after eating some sketchy eggs with diarrhea, fever, and abdominal cramps. What would a Gram stain show?
Gram- rod (Salmonella enterica)
A patient comes in 5 days after eating some sketchy eggs with diarrhea, fever, and abdominal cramps. How does bacteria cause disease?
Intestinal cell invasion…starts in one and spreads to others
A patient comes in with bloody diarrhea after having had really watery diarrhea for the last two days and has had the chills. When asked about anything out of the ordinary in her diet lately, she reported eating a sketchy burger 10 days ago. What is the most likely form of E. coli to cause these symptoms?
EHEC…has Shiga toxin…causes cell defacement –> bloody diarrhea
A patient comes in 4 days after eating raw hamburger on a dare with profuse watery diarrhea. No blood, but has had a fever and chills. What is the likely cause of the symptoms?
ETEC…has a quicker onset than EHEC and has a mechanism/symptoms more similar to cholera than to shigella
A mother comes in concerned about her infant. The child is lethargic, had floppy movements, and has not passed stool in the last two-days. When asked about the babies diet, she says that she is bottle feeding and occasionally sweetens the milk with honey. “Oh, Honey!!” What is likely to present on a gram stain?
A gram+ spore forming rod (Botulinum)
When telling the mother who was giving her infant honey about the dangers of botulism, what other food do you warn her about?
Canned goods
A patient comes in with fairly mild bloody diarrhea, stomach cramps, fever, and has been vomiting for the last 3 days…that is since eating sushi. What bug is causing the symptoms? What is the mechanism?
Vibrio parahaemolyticus
Enterotoxins (hemolysins TDH and/or TRH) form pores in RBCs in gut epithelial cells
A patient comes in with mild dysentery with a fever and chills. What is the most likely causative agent?
Shigella (shiga toxin…inhibs 28S RNA)
We discussed three species of shigella. What was the order of severity? What is a possible complication with shigella?
Sonnei < Flexnori < Dysenteriae
Shigella –> HUS
A person comes in after having 5 days of diarrhea, cramping, abdominal pain, and a fever. He says that a week ago he had chicken that might not have been fully cooked. How does this bacteria cause disease?
Intestinal cell invasion (Campylobacter jejuni…the most common bacterial cause of diarrhea)
A person comes in after having 5 days of diarrhea, cramping, abdominal pain, and a fever. He says that a week ago he had chicken that might not have been fully cooked. What is a possible complication to his infection?
Guillain-barre
“Green beret camp”
A patient comes in after a three-day trip to Mexico with a fever of 103, stomach pains, and diarrhea. What is the name of this infection? Is treatment recommended?
Typhoid fever (Salmonella Typhi)
This patient should be medicated
A patient comes in after a three-day trip to Mexico with a fever of 103, stomach pains, and diarrhea. You ask the patient if she travels often, and she says that her job takes her to many third world countries including India, Mexico, Haiti, and Philippines. What do you recommend she get?
There is a vaccine available for Typhi
Within 7hrs of a company potluck picnic many of the employees spend the next 1-3 days on the can. No fever and feel fine afterwards. What causes this infection?
Staph a toxins (there are 7 of them)
One day after eating at a Chinese buffet, a couple comes in with gut issues. He comes in with watery diarrhea and abdominal cramps, while she presents with nausea and vomiting. What causes his symptoms? What causes her symptoms?
Both are caused by Bacillus cereus, however:
His: enterotoxin that causes intestinal fluid secretion
Hers: preformed enterotoxin that forms holes in membranes
One day after eating at a Chinese buffet, a couple comes in with gut issues. He comes in with watery diarrhea and abdominal cramps, while she presents with nausea and vomiting. What would the results of a gram stain show?
Gram+ rods (box-car shaped…spore forming)
Listeria is found in deli meats, soft cheese, and raw milk. How does listeria spread in the body? What are the results of a gram stain?
Utilize actin polymerization in immune cells to drive to other organs (liver)…Trojan horse approach
Listeria is a gram+ rod
Listeria is common in the body, so how is an infection diagnosed?
Bacterium is in a place that is normally sterile…like the blood
A patient comes in with rice water stools. What are the two most likely serogroups that could be found in this patient? What would the results of a gram stain show? What is the mechanism of infection?
Vibrio cholerae 01 or o139
Gram- rod with a single flagellum
Activates adenylate cyclase (similar to how ETEC activated guanylate cyclase)
A patient comes in saying that yesterday she had diarrhea and abdominal cramps…no fever or vomiting, but she is fine today (so why did she come in???). She says the day before that she ate at the Church after mass. What gram+ spore forming bacterium could have caused this illness?
Clostridium perfringens (high inoculum)
You a doctor on a cruise. A large amount of people have come in with the “stomach flu”…vomiting or non-bloody diarrhea. How are you going to diagnose the infection? What causes the infection
PCR assays will determine it is a norovirus
Inflammatory response to the virus causes the infection
What is the most likely cause of diarrhea worldwide?
Rotovirus
Over half a million kids die from this every year around the world…there is a vaccine used here in the US
What is required for a diagnosis of “food poisoning”?
Symptoms begin in 0.5-6hrs
Toxin had to be pre-formed (food had to be kept in ideal conditions)
What is dysentery?
Frequent, small bowel movements with blood and mucus…accompanied by rectal pain and spasms
What are some differences between amebic and bacillary dysentery?
Bacillary dysentery will be sudden, have a fever/chills/pus, and has an acute course
After broad-spectrum antibiotic treatments, a C. diff infection may occur. What is the mechanism of infection? Should it be cultured?
Exotoxins…cause cell death, shallow ulcers, and pseudomembranes…may eventually invade
No reason to culture…obligate anaerobe
