Enterobacteriaceae Flashcards
Enterobacteriaceae spp.- Gram, where does it reside, spores?, o2,\
- Gram neg
- Reside in digestive tract (intra/extracellular)
- do not form spors
- faculatative anaerobes
what is a common factor of enterobacteriaceae to secrete its toxins
Have needle like protein complexes called secretion systems that secrete exotoxins into host cells
How do you differentiate different types of enterobacteriaceae (+ what do u use to do this)
Can ferment lactose into lactic acid in macconkeys agar (causing it to turn pink)
What are the lactose fermenting enterobacteria (2)
- E. coli
- Klebsiella pneumoniae
What are the non lactose fermenting enterobacteria (3)
Salmonella spp
Shigella
Yersinia
Where does e coli usually reside + produce
Reside in colon normally
-produces vit K
What human pathologies can e coli cause + how is it typically transfered
- Food poisining
- UTIs
- Peritonitis
-ingestion of food/drink contaminated w fecal matter
What are the 3 main pathotypes of e coli (antigen they present + what does it mean)
O- LPS
H- flagellin
K- Capsul
What is enterohemorrhagic e coli (EHEC) due to and whatt type of toxins does it produce (+ what do the toxins do)
Undercooked beef, unwashed vegs/eggs
Shigga toxins- disruption of gut endothelial cells
What are symptoms enterohemorrhagic e coli (EHEC)
- Cramps/ watery diarrhea
- Hemolytic uremic syndrome (kidney failure)
What is the cause of 95% of UTIs and what is the virulece factor of it
Uropathgenic e coli
- Virulence factors include P fimbriae and type I fimbriae which help bacteria attach to urinary tract epithelial cells
- inflamation triggered by LPS
Klebsiella pneumoniae- lactose fermenting?, whos it mc in, assocuated syndrome
lactose fermenting
- mc in chronically ill hospital pts.
- Associated w ankylosing spindylititis (autoimune infection triggered by it)
What is peritonitis and what is the mc cause of it
Damage to the digestive tract usually results in release of bacteria into the normally sterile peritoneum
-e coli mc cause
What are the 2 subspecies of salmonella spp that cause salmonellosis + what foods is it caused by
Non typhoidal serotypes:
- S typhimurium
- S enteritidis
-Eggs, poultry, pork, beef, vegs contaminated w animal waste
What subspecies of salmonella spp cause human disease
S. enterica
Pathology of salmonellosis + when do symptoms appear
6-72hrs after exposure
Large numbers of bacteria enter digestive tract
Bacteria invade intestinal epithelial cells (replication) and induce a strong immune response (LPS, damage)
What salmonella spp cause enteric (typhoid) fever (2)
Typhoidal serotypes
- S typhi
- S. paratyphi
How is typoid fever transmitted and normal incubation period
Oral-fecal transmission (contaminated food/drink)
8-14 days
What are the symptoms of typoid fever
w 1-2-high fever, diarrhea, tiredness, headache, loss of appetite, rash
w3-4- usual resolution
Shigella- lactose fermenting?, flagella? what does it typically cause
Cause of shigellosis (food poisoning)
- non lactose fermenting
- no flagella
transmission and typical incubation time of shigella
12-48 hrs
fecal-oral route
contaminated water, raw meats/vegs
Pathology of shigellosis
Bacilli enter thru specialized epithelial cells called m cells and then can enter neighboring cells causing tissue damage thru LPS
-may produce shiga toxins
Symptoms of shigellosis
Shigellosis usually presents with diarrhea (mild to severe, watery to dysentery) and abdominal pain.
Yersinia spp: what are the 2 species of it and what do they produde
- Yersinia enterocolitica–> yersiniosis
- Yersinia Pestisis–> plague
-Capable of producing virulence factors that prevent production of immune factors (cytokines), increase resistance to phagocytosis and enhance intracellular survival.
Yersiniosis- what is it, due to what, pathology
Type of food poisioning
-insuficiently cooked pork/ contaminated milk
Enters gut and migrates to gut lymphoid tissue where they replicate causing mucosal ulceration (bloody stool)
Yersinia pestis (plauge)- how was it transmitted
Humans become infected through flea bites (regurgitate bacteria), direct contact with contaminated animal tissues (rats) or through inhalation of infectious aerosols
what is the clinical presentation of yesinia pestis (plauge)
Bacteria carried to lympatic tissue where they replicate in large numbers
- bubonic plaque due to enlarged lymph nodes
- Bacteremia is comon causeing necrosis
What is the clinical triade of autoimmune syndrome following bacteria inf
- Eye inflamation
- Inflammation of urethra/cervix
- Arthritis of large jts.
Reactive arthritis (reiters syndrome) due to what bac (2)
Salmonella spp
Shigella spp.
What are the toxins enterotoxigenic e coli (ETEC) (2)
Heat labile enterotoxin
Heat stabile enterotoxin
What does ETEC caused by and symptoms
Intense and prolonged secretion of ions (especially Cl-) leading to watery diarrhea with nausea and cramps
