Exam 3: Gram Negative Bacilli Flashcards
VFs of enteric E. coli species
enterotoxins, O antigen (LPS endotoxin), capsules
Enterotoxins are
exotoxins that cause secretion and diarrhea
O antigen
LPS endotoxin
E. coli lab ID
anaerobic gram-negative rod
do e.coli species form spores?
no
Are E. coli species facultative anaerobes or aerobes?
anaerobes
Which bacteria are part of the enterics group
E. coli, shigella, salmonella
E. coli colonizes where
lower GI tract
what is the most common aerobic and non-fastidious bacterium in the gut?
E. Coli
Enterics reduce
nitrate to nitrite
what would a positive nitrite on a dipstick mean?
you have an enteric pathogen causing the UTI
enterics are ____ when introduced to ____ _____ ____
opportunistic, normally sterile sites
what is the most common cause of UTIs? Accounts for up to 90% of cases of cystitis and pyelonephritis in healthy young women
E. Coli
how are pathogenic strains of E. coli that cause diarrhea organized?
grouped by virulence properties (toxins and invasiveness)
groups of e. coli
enterotoxigenic, enteroinvasive, enterohemorrhagic
what bacteria accounts for 70% of traveler’s diarrhea?
enterotoxigenic e. coli
enterotoxigenic e. coli is spread by
water and food that has been contaminated by feces
enterotoxigenic e. coli presents with
severe watery diarrhea
2 enterotoxins that cause severe watery diarrhea in enterotoxigenic e. coli
Shiga toxin, labile toxin
shiga toxin
produced by both e. coli and shigella – inhibits synthesis, causing cell death
which toxin causes cell death by inhibiting protein synthesis?
shiga toxin
this toxin stimualtes Cl secretion out of the cell and blocks absorption of sodium
labile toxin
true or false, enterotoxigenic e. coli invade and causes inflammation
false
which strain of e. coli is the only to NOT cause inflammatory diarrhea
enterotoxigenic e. coli
causes inflammation and dysentery of the large intestine
enteroinvasive e. coli
what happens when enteroinvasive e. coli invades the mucosa of the large bowel
ulcerates it
what will be seen in the tool of someone with enteroinvasive e. coli?
blood and pus
what bacteria presents similar symptoms but in a milder form like shigellosis
enteroinvasive e. coli
uses invasion plasmid antigens and injects them into enterocytes –> enterocytes engulf bacteria in a phagosome which bacteria escape and then use cytoskeletal actin filaments to create “tails” for themselves –> propel to the next cell and invade, destroying enterocytes and creating FOCAL ULCERS
enteroinvasive e. coli
enteroinvasive e. coli is primarily seen in what population?
children younger than 5 in DEVELOPING NATIONS
bloody diarrhea in DEVELOPED NATIONS & can lead to HUS and permenant kidney damage
Enterohemorrhagic e. coli (O157:H7)
HUS
hemolytic uremic syndrome
hemolytic uremic syndrome
hemolytic anemia (RBC hemolysis), renal failure, thrombocytopenia
t/f antiobiotic treatment is effective against enterohemorrhagic e. coli
false
jack in the box
enterohemorrhagic e. coli
what is the main source of enterohemorrhagic e. coli
contaminated animal products
what is the infectious dose of enterohemorrhagic e. coli?
100 bacteria
what is the bacteria that is behind the reason you should not eat uncooked hamburger
enterohemorrhagic e. coli
where else is enterohemorrhagic e. coli found (other than undercooked hamburgers)
fruits, vegetables, ground water (due to contamination by animal waste)
VF of enterohemorrhagic e. coli
cell wall receptor that can fuse with the host cell membrane and shiga toxin
is enterohemorrhagic e. coli self limiting?
no
shiga toxin can get reabsorbed where?
into renal tissue
shiga toxin causes
capillary thrombosis and inflammation of the colonic mucosa
VF of pseudomonas aeruginosa
can survive and multiply in wide range of environments
exotoxin A
exoenzyme s
phagocytosis-resistant slime layer
Exotoxin A
pseudomonas aeruginosa
shuts down protein synthesis and causes CELL DEATH
exoenzyme S
pseudomonas aeruginosa
transported directly into host cells and induced apoptosis
what is present outside the cell wall in pseudomonas aeruginosa that helps resist phagocytosis?
mucoid polysaccharide slime layer
lab ID of pseudomonas aeruginosa
aerobic gram-negative rods with single polar flagellum; characteristic green pigmentation on culture and fruity odor
cultured a bacteria and it showed up green with a fruity odor… this is most like
pseudomonas aeruginosa
famous for hot tub folliculitis
pseudomoas aerugniosa
pt presents with red itchy rash all over body and said they went hot tubbing recently
pseudomonas aeruginosa
pseudomonas aeruginosa is a common inhabitant of
soil and water
pseudomonas aeruginosa isa an opportunistic pathogen therefore
there must be some sort of breakdown in the host defense
common cause of nosocomial infections esp. in immunocompromised
pseudomonas aeruginosa
what frequently contaminates ventilators, IV solutions, meds, anesthesia equipment
pseudomonas aeruginosa
what is the most common bacterial pathogen to colonize and infect patients with cystic fibrosis?
pseudomonas aeruginosa
otitis externa esp in diabetics is usually caused by
pseudomonas aeruginosa
why should you not sleep with contacts in?
pseudomonas aeruginosa can cause corneal ulcers
environmentally contaminated wounds by pseudomonas aeruginosa can cause ____ from an open fracture
osteomyelitis
which bacteria is notoriously multidrug resistant and always requires susceptibility testing?
pseudomonas aeruginosa
bordetella pertussis VF
surface protein: filamentous hemagglutinin (FHA)
Pertussis toxin
Tracheal cytotoxin (TC)