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Infectious Disease Final > Lecture 9 -- Vibrio, Campylobacter, and Helicobacter > Flashcards

Lecture 9 -- Vibrio, Campylobacter, and Helicobacter Flashcards

1
Q

differentiate between the growth conditions of vibrio cholerae, campylobacter jejuni, and helicobacter pylori

A

vibriocholerae = facultative
campylobacter jejuni and helicobacter pylori = microaerophilic

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2
Q

what diseases does vibrio cholereae cause?

A

cholera (watery diarrhea

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3
Q

state which have urease enzyme between:
vibrio cholereae
campylobacter jejuni
helicobacter pylori

A

only helicobacter pylori has urease

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4
Q

vibrio are gram _______ and oxidase ____
what conditions do they grow in?
give their shape and general characteristices

A

vibrio are gram NEGATIVE
facultative anaerobic bacteria
oxidase negative
curved rods with polar FLAGELLA

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5
Q

true or false

vibrio are NEVER commensal

A

true

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6
Q

in order for a significant vibrio disease to occur, what must happen?

A

a siginificant number of the vibrio must be ingested

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7
Q

where are vibrio primarily found?
what do they require for growth

A

in water. require NaCl for growth

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8
Q

cholera is a severe _____ disease

A

diarrheal

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9
Q

name the toxins of vibrio cholereae

A

endotoxin – LPS/LOS (bc gram negative)

cholera toxin

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10
Q

explain in detail the cholera toxin – its structure and how it accomplishes its goal

A

the cholera toxin (A2B5) is carried on a bacteriophage which binds to the vibrio cholereae sex pilli.

this causes the activation of adenylate cyclase which leads to the overproduction of cAMP and an excess of ions leaving the cell. this causes fluid also to exit = diarrhea

the cell dies due to the osmotic pressure

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11
Q

what is the “classical” vibrio cholerae serotype, responsible for 7 major pandemics?

A

VO1 El Tor

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12
Q

what is a newer strain of vibrio cholerae?

A

VO139 Bengal

the 1st non-VO1 strain.
cause of major disease in 1992

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13
Q

explain how VO139 Bengal was able to cause major disease in 1992

A

it gained the ability to make a capsule
this mutation traced to the insertion of a NEW SEQUENCE in the O1 gene. this created a new virulent strain.

caused major disease bc previous VO1 exposure provided no immunity to this new strain

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14
Q

what are the 4 species of campylobacter associated with human disease?

A

campylobacter….

jejuni
coli
fetus
upsaliensis

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15
Q

explain the growth conditions of campylobacter jejuni

A

MICROAEROPHILIC – like to grow in low oxygen bc they dont have CATALASE that can inactivate peroxide, superoxide that are only present in high O2 environments

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16
Q

what kind of diseases does campylobacter jejuni cause?

A

gastroenteritis and septicemia, watery diarrhea, dysentery (infection of the intestines)

EXTRAINTESTINAL INFECTIONS — Guillain-barre syndrome

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17
Q

how can someone get campylobacter jejuni?

A

carried by animals and also by consuming unpasteurized milk

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18
Q

does campylobacter contain urease?

A

no

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19
Q

explain the structure of campylobacter jejuni.
gram positive or negative?

A

thin, curved GRAM NEGATIVE rods

20
Q

is campylobacter jejuni motile?

A

YES – has polar flagellum

21
Q

which is more common — campylobacter jejuni or salmonella?

A

campylobacter jejuni

22
Q

what does it mean to say that campylobacter jejuni are zoonotic

A

they are commonly in animals – along with other campylobacter species

23
Q

what extraintestinal infections does campylobacter jejuni cause? explain what it is

A

guillan barre syndrome

autoimmune disorder of the PNS. causes progressive, transient muscle weakness.

24
Q

explain how guillan barr syndrome is an autoimmune disorder

A

the antibodies created against the campylobacter jejuni and upsaliensis pathogen attack the peripheral nervous tissue instead

25
Q

name the campylobacter toxins and their function

A

CDT and LOS/LPS

CDT = cytolethal-distending toxin (AB2 exotoxin)
has DNase activity and causes cell cycle arrest

LOS/LPS are classic endotoxins to gram negative bacteria

26
Q

what are the only known bacteria that can survive in the stomach?

A

helicobacter

27
Q

explain helicobacter classification

A

there are 2 groups — gastric and enterohepatic

gastric – helicobacter pylori

enterhepatic – helicobacter cinaedi and fennelliae

28
Q

which helicobacter causes gastritis, ulcers, and gastric cancer?

A

the gastric helicobacter – h. pylori

29
Q

does h. pylori contain urease?

A

YES — this is used to make ammonia and CO2 from urea which counteracts the acid of the stomach — raises the pH so that h. pylori can survive in the stomach.

VERY UNIQUE

30
Q

Explain the growth conditions of H. pylori

A

microaerophilic

31
Q

where is h. pylori found?

A

in humans and gastric secretions

32
Q

how does h. pylori adhere to cell surfaces?

A

OMPs

33
Q

flagella are characteristic features of bacteria that infect where?

A

the stomach

34
Q

explain the structure of H. pylori
is it gram positive or negative?

A

curved or spiral GRAM NEGATIVE rods
when mature = coccoid form (spherical)

35
Q

is H. pylori catalse positive or negative?

A

positve

36
Q

is h pylori mobile

A

YES – highly motile
has flagella
characteristic of bacteria that infect the stomach

37
Q

what is so dangerous about H. pylori?

A

they can establish a chronic colonization of the stomach — prone to stomach cancer

38
Q

explain the enzymes of H. pylori

A

bacterial acid-inhibitory protein

urease activity

mucinases & phospholipases

39
Q

does h. pylori have adhesins?

A

yes – OMPs
to adhere to gastric epithelium

40
Q

what is the function of mucinases and phospholipases in h. pylori?

A

mucinases — breaks down mucus membranes in the stomach (necessary for infection)

phospholipases – break down cell membranes

41
Q

what kind of toxins does h. pylori contain

A

vacuolating cytotoxin A (VacA) – pore forming exotoxin that causes damage to gastric epithelium. makes vacuoles in the cells

Cag – cytotoxin associated gene (cagA)
-this is delivered by a TYPE 4 SECRETION SYSTEM
-this toxin interferes with p53 (causes programmed cell death)– linked to causing gastric cancer

42
Q

which kind of bacteria have secretion systems?

A

only gram negative can have secretion systems

43
Q

does h. pylori get into the blood

A

no

44
Q

the bacterial classifications mentioned earlier (gastric and enterohepatic) are put into these categories based on what?

A

the site of colonization

45
Q

what kind of clinical diseases does H. cinaedi and H. fenneliae cause?

A

gastroenteritis (may be linked to IBS) and can cause bacteremia (pretty rare)

46
Q

what kind of clinical diseases does H. pylori cause

A

gastritis (acute or chronic)
ulcers

chronic infection – tissue is replaced by fibrotic growth (risk for cancer)

cancer = MALT lymphoma

47
Q
A

Infectious Disease Final (13 decks)

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