Haemophilus - Legionella Flashcards Preview

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Flashcards in Haemophilus - Legionella Deck (24):
1

This is a Gram (-) rod that is ID'd by small rods in CSF. It grows on chocolate agar but not blood agar and requires X and V growth factors on trypstose agar.

Haemophilus influenzae

2

What is the satellite phenomenon of H. flu?

grows on blood agar around Staph. aureus

3

H. flu causes meningitis mostly in un-immunized kids. How does it progress?

initially a mild URI then progresses to fever and systemic signs

4

H. flu causes Epiglottitis and may lead to complete airway blockage. How do patients present?

appear sick, restless, pale or cyanotic, tachycardic

5

Conjunctivitis can result from what type of strains of H. flu?

un-encapsulated

6

H. flu causes Brazilian Purpuric fever. Describe its progression and symptoms.

caused by aegyptius biogroup; initial conjunctivitis, then fever, vomiting and abdominal pain after a few days, then with no treatment it progresses to petechiae, purpura, shock and death

7

What are the virulence factors of H. flu?

virulent strains are capsulated; pili

8

This is a Gram (-) rod with parallel chain rice grain morphology. It is ID'd by gram stain of swab of lesion. It requires factor X for growth.

Haemophilus ducreyi

9

How does one contract H. ducreyi?

STD; individuals are more susceptible when dehydrated

10

H. ducreyi causes what disease? remember, it's an STD

Chancroid - genital ulcers and inguinal adenitis

11

Describe the progression of Chancroid

4-7 d post exposure a papule develops with surrounding edema, then 2-3 d later it develops into a pustule that will rupture and evolve into a painful ulcer

12

This species of bacteria includes H. parainfluenzae, Actinobacillus, Cardiobacterium, Eikenella, and Kingella. They are Gram (-) rods that grow slowly on blood agar.

HACEK species

13

H. parainfluenzae requires ___ factor only

V

14

Where is the HACEK species found and where do individuals commonly get infected by it?

found in normal flora of URT and oral cavity; daycare setting

15

What diseases do HACEK species cause?

Endocarditis, Septic Arthritis, Bite wounds, Peridontal disease

16

This is a G(-) coccobacilli. It is ID'd on Regan-lowe charcoal agar or Bordet-gengou charcoal agar. It's oxidase positive and doesn't grow on MA

Bordatella pertussis

17

Bordatella pertussis causes whooping cough. Describe the progression of this disease.

catarrhal stage: after 7-10 d initial cold symptoms that last 1-2 weeks, most contagious during this stage

Paroxysmal phase: cough becomes frequent and spasmodic with repetitive bursts of 5-10 coughs, vomiting after coughing spell is common

Convalescent stage: coughs are less frequent and severe, may last 1-3 months and they may get neurological events like seizures and encephalopathy

18

In regards to virulence factors, Bordatella pertussis produces pertussis toxin. What does it do?

acts as adhesin and toxin; it causes ADP-ribosylation of a G protein that leads to more cAMP and inhibits phagocytic killing and monocyte migration

19

This is a Gram (-) pleomorphic rod. ID'd by culture on buffered charcoal yeast extract agar, immunofluorescence and pcr. It Gram stains poorly.

Legionella

20

What are clinical clues for Legionaire's disease?

high fever, diarrhea, high PMNs but no organism in gram stain of samples, hyponatremia

21

L. peumophila causes most of the Legionella infections. It is an ____ ____ and signifcant cause of community ____

aquatic saporphyte (lakes, shower heads, AC's); pneumonia

22

This disease caused by Legionella can be described as acute, self-limited, flu-like; malaise, fever, fatigue, and myalgia but pneumonia doesn't develop

Pontiac Fever

23

_____ disease (pneumonia) is usually atypical (non productive cough, non purulent sputum) but more severe than other atypical pneumonia. There is a mild cough and fever - widespread infiltration and multi-organ failure, GI symptoms, systemic signs (fever, dyspnea, DELERIUM, rigors)

Legionnaire's

24

In regards to virulence, outer membrane proteins help Legionella bind to ____ macrophages and once endocytosed, they prevent ____ ____ fusion by blocking acidification. They then replicate until the cell ruptures.

alveolar; phagosome lysosome