Gram Negative Bacteria A

Question 1

Heliobacter pylori

Answer 1

Gram Negative
Microaerophillic
Lophotrichous flagella
colonizes stomach and duodenum
spiral shape - burrows into mucous lining of the stomach
secretes urease that decreases pH of stomach

Question 2

When we are born are we H. pylori positive or negative?

Answer 2

negative

Question 3

70% of persons with gastric ulcers are ___?

Nearly all persons with duodenal ulcer are ___?

Answer 3

1. H. Pylori positive
2. colonized

Question 4

How much of the population is infected with H. Pylori?

Answer 4

30%
1% develop duodenal ulcer
1/3 have peptic ulcer disease

Question 5

Two treatment methods for H. pylori

Answer 5

1. Clarithromycin based triple therapy (PPI, amoxil and metronidazole)
2. Bismuth quadruple therapy (PPI, bismuth subsalicylate, tetracycline and metronidazole)

Question 6

Which type of Yersinia causes the plague? Which doesn’t?

Answer 6

Does - Yersinia pestis
doesn’t - Yersinia enterocolitica

Question 7

Y. enterocolitica characteristics

Answer 7

invasive pathogen that penetrates the gut lining
can enter the lymphatic system and the blood
not a gram staining bacteria
can grow in cold temperatures
motile at room temperature
safety pin appearance

Question 8

How is Y. enterocolitica transmitted?

Answer 8

ingestion of contaminated foods

Question 9

What does Y. enterocolitica cause?

Answer 9

Yersiniosis (severe intestinal inflammation)
release of enterotoxin –> severe pain similar to appendicitis

Question 10

The three types of plagues

Answer 10

bubonic, pneumonic and septicemic

Question 11

what does the bubonic plague cause?

Answer 11

swelling of the lymph nodes, skin blotches and delirium after a few days, can lead to death

Question 12

How is Y. pestis transmitted?

Answer 12

through flea (xenopsylla cheopis) bites

Question 13

What does the toxin of Y. pestis inhibit?

Answer 13

the electron transport chain function

Question 14

Treatment for Y. pestis

Answer 14

streptomycin and gentamicin

Question 15

The gold standard for diagnosis of H. pylori

Answer 15

endoscopy with biopsy; H. pylori IgG serology –> positive antibody screen (2nd test)

Question 16

Yersiniosis

Answer 16

severe intestinal inflammation caused by Y. enterocolitica

Question 17

Why is Y. enterocolitica easy to identify?

Answer 17

Because it grows in cold temperatures and is motile at room temperature

Question 18

Treatment for Y. enterocolitica

Answer 18

ahminoglycosides, chloramphenicol or tetracycline

Question 19

Bordetella pertussis characteristics

Answer 19

gram negative coccobacilli
strictly aerobic
whooping cough

Question 20

how is B. pertussis transmitted?

Answer 20

via droplets spread by coughing, cannot survive outside of URT

Question 21

whooping cough is most common in ages ___ when vaccination level is low. When vaccination level is high the age distribution is shifted to

Answer 21

1-5
adults and young infants without vaccination

Question 22

The incubation period for Bordetella pertussis

Answer 22

1-3 weeks

Question 23

Pertussis toxins inhibit

Answer 23

G protein coupling

Question 24

Lymphocytosis

Answer 24

sensitization to histamine; excess number of lymphocytes (WBCs and B cells)

Question 25

Pertussis toxins cause

Answer 25

lymphocytosis and activation of insulin secreting islet cells (hypoglycemia)

Question 26

Catarrhal Phase

Answer 26

2-3 weeks after incubation, mild coughing and sneezing, highly infectious not very ill

Question 27

Paroxysmal phase

Answer 27

cyanosis and vomiting, leukocytosis

Question 28

Treatment for Bordetella Pertussis

Answer 28

Macrolides (erythromycins, clarithromycins)
Adults - Bactrim (TMP-SMX)

Question 29

Drug of choice for Bordetella Pertussis

Answer 29

erythromycin

Question 30

Bordetella pertussis toxins (6)

Answer 30

1. pertussis toxin (lymphocytosis, hypoglycemia)
2. dermonecrotic toxin (vasoconstriction and ischemic necrosis)
3. filamentous hemagglutin ( attachment of bacteria to ciliated epithelial cells)
4. tracheal cytotoxin (inhibits cilia movement and regeneration of damaged cells)
5. adenylate cyclase toxin (decreased chemotaxis and phagocytosis of bacteria)
6. agglutinogens (attachment to host cells)