Enterobacteriaceae - Fusobacterium nucleatum Flashcards
This type of Enterobacteriaceae is a Gram (-) rod that can be capsulated or noncapsulated. It is oxidase, urease, and citrate negative. It is very motile.
E. coli
E. coli is indole ___ and is a ____ fermenter on MacConkey agar.
positive; lactose
What color is E. coli on EMB agar?
metallic green (lactose ferment)
What does the SIM test look like for E. coli?
no black
What does the TSI slant look like for E. coli?
yellow - lactose fermentation
agar displaced upward - gas formed
E. coli is the #2 cause of ____ in neonates
meningitis
What is the pneumonic for diseases of E. coli?
Golly G PU CAME
E. coli is the #1 cause of this infection. It results in dysuria, suprapubic pain; fever/back pain = progression to polynephritis
UTI
In regards to E. coli, abdominal/pelvic infections can lead to what?
peritonitis, appendicitis, diverticulitis, or visceral abcess
Pneumonia caused by E. coli is ___% of nosocomial pneumonia cases
70
This type of gastroenteritis caused by E. coli attaches to intestinal epithelial cells and destroys microvilli -> decreased fluid absorption -> watery diarrhea. This is the major cause of infant diarrhea in developing countries.
EPEC (enteropathogenic)
This type of gastroenteritis caused by E. coli is referred to as traveler’s diarrhea. It is due to LT-I which is like cholera toxin causing an increase in cAMP and STa which causes an increase in cGMP - both causing fluid loss. Incubation is in 1-2 days and last 3-4 days
ETEC (enterotoxigenic)
This type of gastroenteritis caused by E. coli is from consuming undercooked meat, veggies, and expired milk.It is most common in developed countries. It produces shiga like toxins that disrupt protein synthesis. The infecting dose is 100 bacteria and results in mild to bloody diarrhea with severe abdominal pain
EHEC (enterohemorrhagic)
note: O157:H7 is most common strain in US
This type of gastroenteritis caused by E. coli is rare in developed countries. It is plasmid mediated invasion and destruction of epithelial linings. Symptoms are fever, cramps, watery diarrhea -> dysentery
EIEC (enteroinvasive)
This type of gastroenteritis caused by E. coli is infant diarrhea in underdeveloped countries; it is plasma encoded bacterial adherence (like STACKED BRICKS) -> microvilli shortening. Symptoms include watery diarrhea with vomitting
EAEC (enteroaggregative)
This is a Gram (-) rod that is a lactose NON-fermenter. Its produces black colonies on SS agar (H2S production) and is oxidase negative. It comes from raw or undercooked poultry items and has a high infectious dose
Salmonella - non-typhoidal (NTS)
What disease does NTS cause?
Gastroenteritis: 6-48h incubation
Bacteremia
Describe the process of virulence for Salmonella
traverses intestinal layer through phagocytic M cells in PP.
Salmonella -> membrane ruffles in intest. epithelial cells.
These ruffles trap salmonella and induce their endocytosis.
Causes massive PMN infiltration - PMNs have toxicants that damage the mucosa
This is a Gram (-) rod that is a lactose NON-fermenter. Its produces black colonies on SS agar (H2S production) and is oxidase negative. It is present mostly in developing countries and is more common than NTS.
Salmonella Typhirmurium
What disease does Salmonella Typhirmurium cause?
Enteric (Typhoid) Fever
Typhoid fever has an incubation period of ___-___ days, and starts as non-specific flu. There is diarrhea, and fever. An early sign is ___ spots with bacteria on trunk, bradycardia, ____ (nose bleeds), hepatospenomegaly. There are also GI bleeds due to ulcers.
10-14; rose; epistaxis
Salmonella infects ______ tissues
reticuloendothelial (liver/spleen/BM)
This is a Gram (-) rod that is resistant to gastric acid, is a NON-lactose fermenter on MacConkey agar, is a NON-H2S producer (white colonies) on SS agar. It is oxidase negative.
Shigella (enterobacteriacea)
____ in fecal smears are a strong sign of Shigella
PMNs
What individuals does shigella primarily infect and how is it transmitted?
primarily pediatric; fecal-oral
How is Shigella different than L. monocytogenes?
it’s an extracellular parasite
What disease does Shigella Cause? Describe its symptoms.
Shigellosis: fever, cramps, diarrhea to dysentery; damage to glomerular epithelium
How does Shigella invade?
invades colonic mucosa through M cells and PP (peyer’s patches); phagocytosed into M cells -> multiplication causes apoptosis
Shigella induces marked inflammation but rarely gets into the ____. It spreads from cell to cell via ___ ____
blood; actin tail
This is a Gram (-) rod. It is a non-lactose fermenter and is motile at 25 degrees. It’s zoonotic.
Yersinia (enterobacteriacea)
What causes Yersnia?
raw meat and unpasteurized milk or fecally contaminated water
Yersnia targets what organ?
ileum
note: mesenteric lymph node infection also
Describe the symptoms of a Yersnia infection. How long does it last?
acute diarrhea, low fever, abd. cramps; confused with apendicitis!; lasts 2-3 weeks
What is the most important virulence factor of Yersnia?
70kb plasmid is essential for virulence and codes for at least 6 genes for outer membrane proteins
Yersnia can grow from ___-___ degrees
1-45
This is a Gram (-) rod with a prominent capsule. It is urease positive and citrate positive. It ferments lactose and is oxidase negative.
Klebsiella sp. (enterobacteriacea)
Klebsiella sp. colonizes ___ surfaces in mammals. What disease caused by Klebsiella is most common?
mucosal; pneumonia
Pneumonia caused by Klebsiella sp. is mostly nosocomial. It has an ___ onset; is severe and destructive; ____ colored blood and ___-like sputum are associated with it.
acute; gray-green; jelly
Pneumonia caused by Klebsiella sp. affects which individuals mostly?
alcoholics, elderly, patients with lung disease
Klebsiella sp. causes a few other diseases besides pneumonia. What are they?
UTIs; soft tissue infections; bacteremia
This is a Gram (-) rod, encapsulated, with an intracellular life cycle. When identifying this bacterium, you take sample from lesion to see if there are DONOVAN BODIES inside macrophages. It’s oxidase negative.
Klebsiella granulomatous (enterobacteriacea)
Klebsiella granulomatous is considered a ____ but can also be found in kids and non-sexually active adults
STD
What disease does Klebsiella granulomatous cause?
Granuloma Inguinale
Granuloma Inguinale (caused by Klebsiella granulomatous) has an incubation period of ___-___ weeks and begins as subcutaneous nodules that erode through the skin —> ___ granulomatous lesions that slowly enlarge
1-4; painless
Granuloma Inguinale may eventually destroy the ____ or other organs
penis (oh god)
This is a gram (-) rod, HIGHLY motile, likes a high pH, and has a very foul smell.
Proteus (enterobacteriacea)
How is Proteus (P. mirabalis) ID’d?
lactose non-fermenter, urease +, oxidase negative, SWARMING colonies (due to high motility)
Where can Proteus be found?
human gut, soil, water
What disease does Proteus (P. mirabalis) cause?
UTI’s and wound infections
What 3 virulence factors does Proteus utilize?
adhesins, urease, flagella
This is a Gram (-) pleomorphic rod. It is a STRICT ANAEROBE.
Bacteroides fragilis (Fusobacterium)
How is Fusobacterium ID’d?
anaerobic growth, foul smelling wounds with gas, black growth on bacterioids bile esculin agar
Where is B. fragilis (Fusobacterium) found?
GIT nomal flora
note: causes infection after surgery or perf. bowel
What is the most common infection caused by B. Fragilis (Fusobacterium)?
Intra-abdominal infections
note: may also cause sinusitis, otitis, brain/liver absceses, pneumonia, skin and soft tissue infecitons
What are the virulence factors of B. fragillis (Fusobacterium)
catalase and SOD
