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MOD 2 Final > chapter 9: The Enterics > Flashcards

chapter 9: The Enterics Flashcards

1
Q

main groups

A

enterobacteriaceae
vibrionaceae
pseudomonadaceae
bacteroidaceae

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2
Q

biochemical classification, ability to ferment lactos

A

E coli, and most enterobacteriaceae ferment lactose

salmonella, shigella, and pseudomonas aeruginosa do not

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3
Q

appropriate culture media

A

EMB agar

macConkey agar

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4
Q

EMB agar

A

inhibtis gram positive bacteria
colonies of lactose fermenters become deep purple to black
-E coli are metallic green sheen

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5
Q

macConkey agar

A

bile salts in medium inhibit gram positive bacteria

lactose fermenters are pink-purple

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6
Q

enterics E coli tests

A

presumptive test: nutrient broth with lactose, see if gas formed after day

confirmed test: streak EMB agar plates with water samples see if there are metallic green sheen colonies (E coli)

completed test: metallic colonies placed in broth again, if produce acid and gas then know source is contaminated with E coli

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7
Q

3 major antigens for enterices

A

O antigen
k antigen
h antigen

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8
Q

O antigen enterics

A

most external component of LPS

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9
Q

K antigen

A

kapsule that covers O antigen

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10
Q

H antigen

A

antigenic deterninant
subunits of bacterial flagella
only bacteria that are motile have this

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11
Q

pathogenesis of these organisms produce 2 types of disease

A

diarrhea

varoius other infections like UTIs, pneumonia, bcatermia, sepsis especailly in debilitaed hospitalizedd patients

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12
Q

diarrhea with no cell invasion

-organisms and symptoms

A

watery diarrhea without systemic symptoms
E coli
vibrio cholera
exotoxin causes electrolyte and fluid loss

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13
Q

diarrhea with cell invasion of epithelial cells

A

these bacteria have viruluence factors that bind and invade cell damaging it and causing immune response

-cell death results in red blood cell leakage into the stool

E coli, shigella, salmonella enteritidis

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14
Q

invasion of LNs and bloodstream diarrhea

A

systemic symptoms: fever headache WBC elevated
abdominal pain diarrhea with white and red cells
LN enlargement, bacteremia, sepsis

salmonella typhi, yersinia enterocolitica, campylobacter jejuni

sally tied YER camp

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15
Q

hospital acquired gram negatives or nosocomial gram negatives

A

E coli, klebsiella pneumoniae, proteus mirabiuis, enterobacter, serratia, seudomonas aeruginosa

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16
Q

E coli in gut flora is normal until it acquires virulence factors these factors include

A

mucosal interaction
-adherence with pili and ability to invade intesitnal epithelial cells

exotoxin production
LT and ST
siga like toxin

endotoxin
-lipi A of LPS

ironbinding siderophore
-obtain iron from human transferrin or lactoferrin

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17
Q

diseases caused by E coli in presence of virulence factors include

A

Diarrhea
UTI
Neonatal meningitis
Gram negative sepsis, mostly hospital pts

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18
Q

Enterotoxigenic E coli (ETEC)

A

pili

heat liable toxin (LT)
heat stable toxin (ST)
-inhibit cl- and Na+ reabsorption and cause secretion into lumen which increases water there

stool looks like rice water- just like CHOLERA

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19
Q

enterohemorrhagic E coli (EHEC)

A

pili
secrete powerful SHIGA like toxin (verotoxin)
-inhibit protein syntesis by inhibiting ribosome = intestinal epithelial cell death

diarrhea is bloody
abdominal cramps
hemorrhagic colitis

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20
Q

hemolytic uremic syndrome (HUS)

which infection associated with

A

anemia throboycytopenia and renal failure is associated with infection by EHEC

infected hamnurger meat at fast food chains
cattle is reservoir

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21
Q

enteroinvasive E coli (EIEC)

A

main virulence factor is encoded by plasmid shared by SHIGELLAand E coli
plasmid gives bacteria ability to invade epithelial cells

fever
WBC invade intestinal wall
diarrhea is bloody with white blood cells
(like shigellosis)

22
Q

E coli and UTIs

A

acquisition of pili virulence factor allows E coli to travel up urethra and infect bladdre (cyctitis)

can move further and cause pyelonephritis

burning on urination (dysuria)
peeing frequently
full bladder feeling

23
Q

E coli meningitis

A

common cause of neonatal meningitis during first month of life neonate is most susceptible

24
Q

E coli sepsis

A

most common casuse of gam negative sepsis
hospitalized pts
septic shock due to lipid A of LPS is usually the cause of death

25
Q

klebsiella pneumoniae

capsule?
who and where acquired
foley catherter
presents as
mortality rate
A

encapsulated (O antigen) non motile
causes sepsis in hospitalized pts
UTI in hospitalized pts with foley catheters
hostpitalized pts and alcoholics are prone to this pneumonia

characterized by blood sputum in 50% of cases

destroys lung tissue = cavaties

thick sputum looks like red currant jelly (O antigen capsule color)

mortality rate high

26
Q

proteus mirabilis

A

very motile, grows all over plate
breaks down urea so it is a urea splitting proteus
cross reactions with some rikettsia
common cause of UTIs especially in hostpital acquired infections

27
Q

enterobacter

A

highly motile gram neg rod part of normal flora of intestinal tract
occasionlaly responsible for hostipital acquired infections

28
Q

serratia

A

birght red pigment
UTI
wound infections
pneumonia

29
Q

shigella

  • motitlity
  • fermentation
A

non motile

doesn’t ferment lactose and does not produce H2S (distinguish from E coli and salmonella)

30
Q

shigella

  • hosts
  • main population
  • pathogen or normal flora
  • transmission
A

humans are only hosts
dysentery (inflammation of intestines accompanied by diarrhea): preschool children and people in nursing homes
pathogen
fecal oral (contam water or hand to hand contact)

31
Q

shigella presents how

A

similar to EIEC as it invades intest epithelial cells and releases shiga toxin = cell destruction, white cells arrive in inflammatory reaction

fever, abdominal pain, diarrhea
diarrhea may contain flecks of bright red blood and pus

visualize shazam shigella with his shiga blaster laser, entering intestingal epithelial cells and blasting away at 60S ribosome = epithelial cell death

32
Q

salmonella antigens, where it lives, contamination, is it a lactose fermenter and producer of H2S

A

non lactose fermenter that produces H2S
Vi antigen surrounds O antigen to protect against attack
lives in GI tract of animals and infects humans when contamination of food or water with animal feces
-from chicken and uncooked eggs

33
Q

which salmonella is not zoonotic and only carried by humans

A

salmonella typhi

34
Q

typhoid fever or enteric fever

pathogenesis

A

salmonella typhi
invades intest epithelial cells then regional lymph nodes and seeds in multiple oran systems
-facultative intracelluar parasite inside monocytes

35
Q

typhoid fever symptoms

A

salmonellosis starts 1-3 weeks after exposure
fever, headache, abdominal pain that is diffuse or to right lower quadrant (mimicks appendicitis)

spleen may enlarge’
pt may develop diarrhea and rose spots on the abdomen

36
Q

typhoid fever carrier state

A

people recovering from the fever harbor the typhi in their gallbladders and excrete it constantly
people are asympomatic
-can spread to others

37
Q

salmonella sepsis

certain pts susceptible to what infection

A

salmonella choleraesuis infects lungs brain or bone and does not involve GI tract

people without spleens or pts with sickle-cell anemia are very prone to salmonella osteomyelitis (bone infection)

38
Q

diarrhea from salmonella

A

most common type of salmonella infection
diarrhea is either watery or less commonly contains mucous and trace blood

fever in half of pts
diarrhea from cholera-like toxin (watery diarrhea) and ileal inflammation (mucous diarrhea)

39
Q

yersinia enterocolitica

A

may cause gastroenteritis/diarrhea
related to yersinia pestis which casuesees the bubonic plague

  • animals are source of transmision, fecal oral
  • symptoms resemble appendicitis
40
Q

pathogenesis of yersinia enterocolitica is 2fold

A

invasion all the way into regional LN and bloodstream
mesenteric lymph nodes swell and sepsis can develop

enterotoxin: secrete enterotoxin similar to heat stable enterotoxin of E coli that causes diarrhea

41
Q

vibrio cholera

A

curved gram neg rod with single polar flagellum
fecal oral route contamination
no epithelial cell invasion
bacteria attach themselves to epithelial cells and elaborate choleragen toxin (cAMP production)
rice water stool diarrhea
often death due to dehydration

42
Q

organism that is marine bacterium that causes gastroenteritis after ingestion of uncooked seafood
leading cause of diarrhea in japan

A

vibrio parahaemolyticus

43
Q

campylobacter jejuni is one of three most common organisms causing ____ in the world

-other two?

A

diarrhea

other 2: ETEC and rotavirus

44
Q

campylobacter jejuni looks like what

A

Vibrio cholera

45
Q

transmission oc campylobacter jejuni

A

zoonotic disease
fecal oral route with contaminated water most common transmission
-can get from unpasteurized milk

46
Q

clinically camp jejuni

A

fever, headache,
followed by loose, blood diarrhea
invades small intestine and may spread systemically

LT toin similar to that of E coli

47
Q

H pylori

A

most common cause of duodenal ulcers and chronic gastritis

48
Q

99% of GI flora are composed of what

A

obligate anaerobic Gram negative rods from bacteriodaceae family

also in mouth and vagina

49
Q

bacteriodes fragilis

A

has capsule but no endotoxin
no lipid A

-normally has low virulence and is in homeostasis in GI tract

with trauma release of this organism can cause widespread 2ndary infection of abscess formations

may complicate abortion, tubo-ovarian abscess, IUD

50
Q

bacteriodes melaninogenicus can cause and can exhibit what manifestions

A

can cause necrotizing anerobic pneumonia, following GI aspiration

pneumonic and periodontal manifestations

51
Q

fusobacterium may have similar disease manifestations as ____ and rarely be etiology of ___

A

b melaninogenicus

ottitis media

52
Q

anaerobic gram positive Cocci

A

peptostreptococcus
-part of normal flora of mouth, vagina and intestine
-microaerophilic, isolated from abscesses
viridans grp strep

MOD 2 Final (19 decks)

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