Actinomycetes Flashcards Preview

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Flashcards in Actinomycetes Deck (21):
1

Identify the partially-acid-fast positive genera of Actinomycetes.

Nocardia
Rhodococcus

2

Identify the partially-acid-fast negative genera of Actinomycetes.

Streptomyces
Actinomyces

3

List three aerobic actinomycetes.

Nocardia
Rhodococcus
Streptomyces

4

List one anaerobic actinomycetes.

Actinomyces

5

How do we differentiate Nocardia from Actinomyces & streptomyces?

AF Stains
Nocardia red
Actinomyces & streptomyces- blue

6

Nocardia causes infections primarily in what kind of patients?

Immunocompromised patients

7

Which organism causes pulmonary infection in immunocompromised patients?

N. asteroides

8

The cutaneous infections which is usually from traumatic inoculation is caused by_______

N. brasiliensis

9

Cutaneous infections-Traumatic inoculation may develop into _______

Actinomycotic mycetoma

10

List the major illnesses observed in infections related to Nocardia

Immunocompromised patients
-Pulmonary
-dissemination to brain
- cutaneous infections-traumatic inoculation

11

Which organism has high mortality?

Nocardia

12

Describe the microscopic appearance of Nocardia.

Beaded, branching, filamentous GPRs.

13

Describe the plate morphology of Nocardia.

Earthy smell
Slow growing
-often resemble fungi
-has dry, heaped, white to orange, aerial hyphae

14

What is the preferred method used for identifying Nocardia?

HPLC

15

Describe the methods for speciation in identifying Nocardia.

-speciation using hydrolysis of casein, xanthine, tyrosine, or hypoxanthine
- Looking for hydrolysis (+) vs no hydrolysis (-)

16

This organism has negative hydrolysis of casein, xanthine, tyrosine or hypoxanthine.

N. asteroides

17

This organism has casein and tyrosine hydrolysis- Positive

N.brasiliensis

18

Can we differentiate Streptomyces from Nocardia on gram stain?

NO

19

Describe the microscopic appearance of Streptomyces.

GPRs or filamentous, may be beaded

20

This organism is rare in human infections and commercial uses antibiotics, antifungals, and immunosuppressants.

Streptomyces- primarily saprophytes

21

Describe the microscopic appearance of Rhodococcus.

Short, branching gram positive rods