Other Gram ( - ) Bacteria Part I

Question 1

Describe the Gram ( - ) cell wall

Answer 1

LPS = O antigen
endotoxin
core polysaccharide
solid peptidoglycan membrane
Capsule = K antigen

Question 2

Severe pediatric disease:
meningitis
fever
headache, stiff neck  
permanent hearing loss 
sepsis & gangrene 
arthritis and cellulitis

Answer 2

Haemophilus influenza

Question 3

ENCAPSULATED virulent strain of Haemophilus causing upper respiratory tract infections

• Meningitis
• Otitis Media
• Sinusitis

Answer 3

HiB (Type B Strain of Haemophilus influenza)

Question 4

polyribosyl phosphate capsule (PRP)

Answer 4

antiphagocytic property of HiB and important virulence factor

Question 5

a nonmotile, facultatively anaerobic, Gram-negative coccobacillus that requires special growth factors, hemin (factor X) and NAD (factor V) to grow on chocolate agar

Answer 5

H. influenza

Question 6

Why is vaccine against H.influenza important?

Answer 6

Provides IgA for defense against the bacteria in the lining of the lung epithelium. The bacteria has a IgA protease.

Question 7

Complicated COPD in adults by causing pneumonia

Answer 7

H. influenza

Question 8

Gram negative
 Coccobacilli (*with intermediate morphology)
grows in upper respiratory tract
Encapsulated
*No bacteremia
*toxins cause local tissue damage

Answer 8

Bordetella pertussis

ciliated cells poisoned with Nitrous Oxide

Question 9

Paroxysmal Cough + Vomiting

Answer 9

Bordetella pertussis (whooping cough)

Question 10

Vaccination at 1yr, 5yr, 18yrs

Answer 10

B. pertussis

Question 11

kills ciliated epithelial cells of respiratory tract via

1. Filamentous hemagglutinin
2. Pertussin toxin

Answer 11

B. pertussis

Filamentous hemagglutinin attaches to and stops normal ciliary movement

Question 12

Describe the Incubation Stage of B. pertussis infection

Answer 12

Fever and cough after 10 days

Question 13

Describe the Catarrhal Stage of B. pertussis infection

Answer 13

Fever, sneezing, anorexia after 2 weeks

Question 14

Describe the Paroxysmal Stage of B. pertussis infection

Answer 14

Paroxysmal cough lasts 2-4 weeks
coughing+vomiting
toxemia
eye hemorrhage (from coughing)

Question 15

Describe the Convalescent Stage of B. pertussis infection

Answer 15

Lasts 3-4 weeks
pneumonia
seizures
convulsions

Question 16

What culture media would you use to diagnose B. pertussis?

Answer 16

Bordet-Gengou-blood agar charcoal and starch

Question 17

Fastidious
Aerobic
Gram Neg Rods
*No capsule
*Non-motile
3 Zoonotic reservoirs (cattle,swine,goats)

Answer 17

Brucellosis

Question 18

Cell wall has high concentrations of A antigens

Answer 18

B. abortus

Question 19

Cell wall has high concentrations of M antigens

Answer 19

B. melintensis

Question 20

Most virulent species causing Brucellosis

Answer 20

B. melintensis (goats)

Question 21

Pathogen affecting RES cells
(liver,spleen,lymph nodes)
AND all phagocytes EXCEPT monocytes

Answer 21

Brucella

Question 22

Undulating (spiking) fever

Answer 22

Answer: Brucellosis

anorexia, CNS symptoms, bacteria form granulomatous nodules 3days-3mos

Question 23

Gram Neg Rod
Non-spore forming
antiphagocytic capsule
aerobic and facultatively anaerobic
non-motile
biochemically inactive
*Class A bioterrorism agent

Answer 23

Francisella tularensis

Question 24

(non urban) wild animal reservoir;
infection upon skin contact via minor abrasions or ingestion of undercooked wild animals;
deer flies, tick bites;
lab infection;
symptoms similar to plague

Answer 24

Francisella tularensis

Question 25

``` Gram Neg short, pleomorphic encapsulated (antiphagocytic) non-motile grows on simple media Induces apoptosis in host cells septic shock *FDA approved Biosafety level 3 facilities only ```

Answer 25

Yersenia pestis

Question 26

Safety pins on gram stain

Answer 26

Yersenia pestis

Question 27

What are the 2 phases of plague? Which is more deadly?

Answer 27

Bubonic (lymph nodes) and Pneumonic (lungs) - more deadly

Question 28

Describe Endemic plague

Answer 28

pneumonic transmission-person to person via respiratory droplets cyanosis=black death

Question 29

Describe Sylvanic plague

Answer 29

passed via rodent vector (+fleas) swollen lymph nodes= bubos

Question 30

Describe the role of LPS with Yersenia pestis virulence

Answer 30

coagulation disturbances

Question 31

Describe the antiphagocytic properties of the Y. pestis cell wall

Answer 31

VW antigen system V=protein W=lipoprotein prevents intracellular destruction and produced at body temperature

Question 32

3 Extracellular Factors that cause clotting disturbances from Y. pestis

Answer 32

1. Pesticin I = a bacteriocin 2. Coagulase = activates the thrombin system 3. Fibrinolysis = a protein causing clot breakdown

Question 33

Type III secretion system allows Y. pestis to inject these proteins into cytoplasm of macrophages and other immune cells causing apoptosis

Answer 33

YOP= yersenia outer protein

Question 34

Diagnostic methods for Y.pestis

Answer 34

Bipolar staining with Wayson's stain (methylene blue with carbol fuchion *Safety pins

Question 35

``` Gram Neg bacillus Aerobic opportunistic flagella problem in hospitals with ventillators, IV's, Catheters Omnipresent (including gut) ```

Answer 35

Pseudomonas aeruginosa

Question 36

Infection smells like grapes

Answer 36

P. aeruginosa

Question 37

``` Has alginate (mucoid slime layer) Pili for adherence ``` LPS = causes septic shock/antibiotic resistance/suppresses neutrophils and lymphocytes Produces pyocyanin = impairs ciliary function/ tissue damage via oxygen radicals

Answer 37

P. aeruginosa

Question 38

Name 5 Toxins/Enzymes associated with virulence of P.aeruginosa

Answer 38

``` Exotoxin A Exoenzyme S&T Endotoxins Phospholipase C Elastase and Alkaline Protease ```

Question 39

P. aeruginosa: Exotoxin A

Answer 39

Similar in structure to Diptheria toxin Inhibits protein synthesis by ADP-ribosylating EF-2 (G-protein) Causes Dermatonecrosis in burn wounds, corneal damage in ocular infections, and tissue damage in chronic pulmonary infections. Also this toxin is immunosuppressive

Question 40

P. aeruginosa: Exoenzyme S & T

Answer 40

ADP-ribosylates G-proteins including p21 RAS interfering with host cell growth

Question 41

P.aeruginosa: Phospholipase C

Answer 41

Heat labile hemolysin Breaks down lipids and lecithin causing tissue destruction Stimulates inflammatory response

Question 42

P. aeruginosa: Elastase and Alkaline Protease

Answer 42

Destruction of elastin-containing tissues (blood vessels, lung tissue, skin), collagen, immunoglobulins, and complement factors Can produce hemorrhagic lesions (ecthyma gangrenosum) associated with disseminated infection Inactivation of interferon and TNF-Alpha

Question 43

Can transiently colonize the respiratory and GI tract of hospitalized patients Inherently resistant to many abx Can mutate to more resistant strains during therapy Penetration of abx highly dependent on outer membrane pores which can be altered Production of B-lactamases Combination of active abx generally required for successful therapy

Answer 43

P. aeruginosa

Question 44

Pulmonary Infections Burn Wound Infections and other skin and soft tissue infections (life threatening) UTI’s (especially catheterized) External Otitis (malignant OE, swimmer’s ear) Eye Infections and corneal ulceration via contaminated contact lens cleaning fluids Pseudomonal Endocarditis

Answer 44

Pseudomonas aeruginosa

Question 45

cutaneous manifestation of severe, invasive infection by Pseudomonas aeruginosa that is usually seen in immunocompromised(no neutrophils) BURN PATIENTS

Answer 45

Ecthyma Gangrenosum