Unit 7 textbook + Lab book questions

Question 1

What is the primary purpose of microbiology examinations?

Answer 1

the identification of bacterial pathogens

Question 2

What are the two types of dermatophyte test media?

Answer 2

Standard dermatophyte test media (DTM) and Standard Sabouraud dextrose agar

Question 3

Partial hemolysis that creates a narrow band of greenish or slimy discoloration around the bacterial colony us referred to as?

Answer 3

alpha hemolysis

Question 4

Bacteria are small ____ cells.

Answer 4

prokaryotic

Question 5

Bacteria have specific requirements, in what areas?

Answer 5

temperature, pH, oxygen tension, and nutrition

Question 6

What type of fungal organisms have no known sexual stages?

Answer 6

Deuteromycetes

Question 7

The dermatophytes comprise of different organisms in the taxonomic genera?

Answer 7

Microsporum and Trichophyton

Question 8

3 common Dermatophytes?

Answer 8

Microsporum canis, Microsporum gypseum, and trichophyton mentagrophytes

Question 9

Dermatophytes are classified by what habitats?

Answer 9

Anthropophilic, zoophilic, geophilic

Question 10

Anthropophilic live on?

Answer 10

people

Question 11

Zoophilic live on?

Answer 11

animals

Question 12

Geophilic live in?

Answer 12

existing as freeliving saprophytes in the soil

Question 13

What is one test that us used when Dermatophyptes are found on the hair shaft?

Answer 13

1. pluck hairs
2. place on slide with 1 - 2 gtt of 10% KOH
3. After 2-10 min small globular arthrospores are visible on the shaft
   visualized microscopically

Question 14

Another Dermatophyte testing is using a Wood lamp , what is it?

Answer 14

an ultraviolet light source that may be used to screen suspect lesions for dermatophyte infection, but results may be ambiguous
50% success - positive result is a clear, apple green glow

Question 15

What can you use to culture dermatophytes?

Answer 15

• ## most common is DTM - which contains an indicator that turns red in the presence of most dermatophytes.

Question 16

What media is available to culture dermatophytes using DTM in tube format?

Answer 16

faster - RSM - rapid sporulation medium
faster - ESM - enhanced sporulation medium - both have color indicators and accerlate formation of macroconidia for ID
slower - Sabouraud dextrose agar - also promotes early formation of macroconidia but no color change

Question 17

How do you collect samples for Dermatophytes?

Answer 17

clean the skin lesion to remove some of the surface contamination and collect specimens from the lesion periphery, leave at room temp. - observe daily, at first sign, wet prep using tape and lactophenol cotton blue stain - on slide

Question 18

Test results for DTM are what color

Answer 18

positive - red in DTM
Teal in ESM or other media
support by microscope exam

Question 19

Fungal cultures, non-dermatophytes are plated on what medium?

Answer 19

on blood agar or sabouraud dextrose agar

Question 20

What is Bacillus anthracis?

Answer 20

a bacterium that causes amthrax in animals, humans, cattle, sheep, and guinea pigs

Question 21

Pasturella is?

Answer 21

a genus of Gram-negative, facultatively anaerobic bacteria.