Lecture 9 -- Vibrio, Campylobacter, and Helicobacter

Question 1

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

Answer 1

vibriocholerae = facultative
campylobacter jejuni and helicobacter pylori = microaerophilic

Question 2

what diseases does vibrio cholereae cause?

Answer 2

cholera (watery diarrhea

Question 3

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

Answer 3

only helicobacter pylori has urease

Question 4

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

Answer 4

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

Question 5

true or false

vibrio are NEVER commensal

Answer 5

true

Question 6

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

Answer 6

a siginificant number of the vibrio must be ingested

Question 7

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

Answer 7

in water. require NaCl for growth

Question 8

cholera is a severe _____ disease

Answer 8

diarrheal

Question 9

name the toxins of vibrio cholereae

Answer 9

endotoxin – LPS/LOS (bc gram negative)

cholera toxin

Question 10

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

Answer 10

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

Question 11

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

Answer 11

VO1 El Tor

Question 12

what is a newer strain of vibrio cholerae?

Answer 12

VO139 Bengal

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

Question 13

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

Answer 13

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

Question 14

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

Answer 14

campylobacter….

jejuni
coli
fetus
upsaliensis

Question 15

explain the growth conditions of campylobacter jejuni

Answer 15

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

Question 16

what kind of diseases does campylobacter jejuni cause?

Answer 16

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

EXTRAINTESTINAL INFECTIONS — Guillain-barre syndrome

Question 17

how can someone get campylobacter jejuni?

Answer 17

carried by animals and also by consuming unpasteurized milk

Question 18

does campylobacter contain urease?

Answer 18

no

Question 19

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

Answer 19

thin, curved GRAM NEGATIVE rods

Question 20

is campylobacter jejuni motile?

Answer 20

YES – has polar flagellum

Question 21

which is more common — campylobacter jejuni or salmonella?

Answer 21

campylobacter jejuni

Question 22

what does it mean to say that campylobacter jejuni are zoonotic

Answer 22

they are commonly in animals – along with other campylobacter species

Question 23

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

Answer 23

guillan barre syndrome

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

Question 24

explain how guillan barr syndrome is an autoimmune disorder

Answer 24

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

Question 25

name the campylobacter toxins and their function

Answer 25

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

Question 26

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

Answer 26

helicobacter

Question 27

explain helicobacter classification

Answer 27

there are 2 groups --- gastric and enterohepatic gastric -- helicobacter pylori enterhepatic -- helicobacter cinaedi and fennelliae

Question 28

which helicobacter causes gastritis, ulcers, and gastric cancer?

Answer 28

the gastric helicobacter -- h. pylori

Question 29

does h. pylori contain urease?

Answer 29

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

Question 30

Explain the growth conditions of H. pylori

Answer 30

microaerophilic

Question 31

where is h. pylori found?

Answer 31

in humans and gastric secretions

Question 32

how does h. pylori adhere to cell surfaces?

Answer 32

OMPs

Question 33

flagella are characteristic features of bacteria that infect where?

Answer 33

the stomach

Question 34

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

Answer 34

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

Question 35

is H. pylori catalse positive or negative?

Answer 35

positve

Question 36

is h pylori mobile

Answer 36

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

Question 37

what is so dangerous about H. pylori?

Answer 37

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

Question 38

explain the enzymes of H. pylori

Answer 38

bacterial acid-inhibitory protein urease activity mucinases & phospholipases

Question 39

does h. pylori have adhesins?

Answer 39

yes -- OMPs to adhere to gastric epithelium

Question 40

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

Answer 40

mucinases --- breaks down mucus membranes in the stomach (necessary for infection) phospholipases -- break down cell membranes

Question 41

what kind of toxins does h. pylori contain

Answer 41

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

Question 42

which kind of bacteria have secretion systems?

Answer 42

only gram negative can have secretion systems

Question 43

does h. pylori get into the blood

Answer 43

no

Question 44

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

Answer 44

the site of colonization

Question 45

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

Answer 45

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

Question 46

what kind of clinical diseases does H. pylori cause

Answer 46

gastritis (acute or chronic) ulcers chronic infection -- tissue is replaced by fibrotic growth (risk for cancer) cancer = MALT lymphoma