GI Lower Bacterial Infections II Flashcards
What does Vibrio spp. look like?
G- flagellated curved rod
What distinguishes Vibrio sp. from E. coli?
Vibrio: Oxidase + (shows up purple), flagella
E. coli: Oxidase -
What are symptoms of Vibrio parahaemolyticus infection?
Bloody diarrhea
Stomach cramps, nausea, vomiting
Fever
Sx less than a week
How do you diagnose V. parahaemolyticus?
Cultures of stool, wound, blood
What is the mechanism of action of V parahaemolyticus infection?
Enterotoxin (hemolysins)
Food reservoirs for Vibrio parahaemolyticus?
Uncooked shellfish
What does listeria look like?
Gram positive bacillus
What hemolysis does listeria exhibit?
Beta hemolysis but only directly under colonies
Who are more vulnerable for listeriosis, causing a more severe illness?
Older adults
Pregnant women
Newborns
Immunocompromised
What are the causes of death with listeriosis while vulnerable?
Meningitis and sepsis
How do you diagnose listeriosis?
Positive ID is bacteria found in normally sterile site
What is the mechanism of injury for listeria?
Invasion of macrophage (trojan horse)
Liver is major target
What are reservoirs for listeria?
Sprouts Deli meats/hot dogs Smoked salmon Soft cheeses Raw milk
What are shigella closely related to?
E. coli
How is shigella transmitted?
Fecal oral
What are symptoms of shigella sonnei infection?
Bloody diarrhea (sometimes not) Fever Cramps 1-2 days following exposure 5-7 day resolves
What is defined as Frequent small bowel movements with blood and mucus, accompanied by rectal pain and spasms?
Dysentery
Easy way to tell E. coli from e. coli?
Shigella have no flagella
Lactose negative and H2S negative
What cells are initial invasion points of shigella?
M cells
What do shigella use to move around in a host?
Actin
How do you treat shigella?
Usually resolves
Can be systemic so use antibiotics
What are possible complications of shigella?
Hemolytic uremic syndrome
Reactive arthritis
What does Shiga toxin affect?
Vascular endothelial cells (most severe dysentery)
What strains of E. coli cause disease?
ETEC and EHEC
What diseases are caused by E. coli?
Diarrhea
Urinary tract infection
Neonatal sepsis
Gram negative sepsis
What are the E coli that produce sign toxin called?
Enterohemorrhagic E. coli (EHEC)
Which E coli is more responsible for outbreaks in U.S.? Which is more common in traveler’s diarrhea/children’s diarrhea?
EHEC: US outbreaks
ETEC: Traveler’s/Children
What are common symptoms for E coli infection?
Profuse watery diarrhea
Nausea with or without vomiting
Chills
Long incubation period for EHEC
Should you treat E coli poisoning?
Not really. Will kill normal gut flora as well
What are used for tracking E coli outbreaks?
Commercial PCR and Ig-based kits
What are common EHEC/ETEC reservoirs?
Beef, spinach, etc.
What is primary reservoir for V. cholerae?
Water
What does cholera toxin do?
Activates adenylate cyclase, leading to Cl excretion and Na absorption (water follows Cl)
Which serogroups of V. cholerae produce cholera toxin?
O1 and O139
What does cholera look like?
Profuse watery diarrhea (rice-water stools)
Vomiting
Rapid HR
SEVERE dehydration
What is the only reliable method of identifying V. cholerae?
Culture of stool
How do you treat cholera?
Rehydration therapy
Sometimes antibiotics if super serious
What is the common source for Salmonella Typhi?
untreated water (humans are only carriers)
What does typhoid fever look like?
High fevers (103-104)
Weakness, headache
Stomach pain, loss of appetite, diarrhea OR constipation
Rash of flat, rose-colored spots
How do you treat typhoid fever?
Vaccine
Antibiotics are recommended
What does C. diff look like?
Gram + bacilli, spore forming
What do C. diff exotoxins cause?
Cell death, shallow ulcers, pseudomembranes
How do you diagnose C diff?
Toxin detection
How do you treat C. diff?
Antibiotics: Metronidazole, vancomycin
If severe, then bowel resection
Maybe fecal transplant
