INDIGENOUS ORGANISMS ASSOCIATED WITH SKIN AND MUCOSAL SURFACES

Question 1

Mucosal surfaces and their associated indigenous organisms
function together to

Answer 1

protect exogenous pathogens from entering the body.

Question 2

Colonization of
commensal normal flora inhibits

Answer 2

the growth of potential pathogens by competing for nutrients on
the surface of mucous membranes

Question 3

Most indigenous species have a commensal or mutualistic
relationship with

Answer 3

the mucous membrane by coexisting or equally benefiting from one another.

Question 4

The
following mucosal surfaces

Answer 4

Skin
Conjuctiva
oral cavity & nasal passages
lower respiratory tract
GI tract
Vaginal tract

Question 5

Skin organisms

Answer 5

S. aureus
S. epidermidis
Corynebacterium
and Propionibacterium acnes

Question 6

Conjuctiva (eyes) organisms

Answer 6

S. aureus
S. epidermidis
S. pneumoniae
H. influenzae
Neisseria
species
Candida
Aspergillus
and Penicillium

Question 7

Oral cavity and nasal passages organisms

Answer 7

S. aureus
S. epidermidis
S. pneumoniae
S. pyogenes
S. mitis
S. salivarius
S. mutans
Enterococcus faecalis
H. influenzae
Neisseria species
E. coli
Proteus
Corynebacterium
Lactobacillus
Actinomycetes
Candida
Mycoplasmas
and Cryptococcus

Question 8

Lower respiratory tract organisms

Answer 8

Staphylococcus
Streptococcus
Fusobacterium
Acinetobacter
Pseudomonas
Sphingomonas
Prevotella
Megasphaera
Candida
and Aspergillus species

Question 9

GI tract organisms

Answer 9

Lactobacillus
Clostridium
Bacteroides
Enterococcus
Streptococcus
Corynebacterium
Enterobacter
and Helicobacter species

Question 10

Genitourinary tract (vaginal) organisms

Answer 10

Lactobacillus
S. aureus
S. epidermidis
E. faecalis
S. pneumoniae
S. pyogenes
Neisseria species
E. coli
Proteus species
and Corynebacterium species

Question 11

Neisseria species biochemical reactions:

Answer 11

Biochemical reactions:
Catalase +
Oxidase +
Nitrate reduction +

Question 12

Neisseria species Gram stain

Answer 12

GND (diplococci)

Question 13

Neisseria species Growth requirements

Answer 13

aerobic and facultative anaerobe, grow best in a humid, 5–10% CO2
environment at 35–37 °C

Question 14

Neisseria species Colony morphology

Answer 14

small, white to gray-brown, smooth, butter-like, and translucent on
sheep blood agar with a green hue on agar underneath colonies possible

Question 15

Acinetobacter species biochemical reactions:

Answer 15

Oxidase −
Catalase +
Motile −
Nitrate reduction −

Question 16

Acinetobacter species gram stain

Answer 16

GNC (coccobacilli)

Question 17

Acinetobacter species growth requirements:

Answer 17

aerobic and facultative anaerobe, grows best at 35 °C in ambient air
or a CO2-rich environment

Question 18

Acinetobacter species colony morphology:

Answer 18

smooth, round, mucoid, opaque to white colonies on sheep blood
agar.

Question 19

Pseudomonas aeruginosa biochemical reactions:

Answer 19

Motility +
Oxidase +
Catalase +
Urease −
Indole −
Methyl red −
Voges–Proskauer −
Tryptic soy agar K/K

Question 20

P. aeruginosa gram stain:

Answer 20

GNRs

Question 21

P. aeruginosa growth requirements:

Answer 21

obligate aerobe, grow best at 35 °C in ambient air or a CO2-rich
environment

Question 22

P. aeruginosa colony morphology:

Answer 22

grayish white, translucent to opaque, circular with irregular edges on
sheep blood agar. Colorless, transparent, circular on MacConkey agar. Colonies are smooth
or mucoid, if swarming occurs. Produces a grape, or corn tortilla-like odor.

Question 23

Clostridium perfringens biochemical reactions:

Answer 23

Indole –
Urease –
Lecithinase +
Nagler test +
Reverse CAMP test +
Vancomycin S
Kanamycin S
Colistin R

Question 24

Clostridium perfringens gram stain:

Answer 24

Gram-positive to Gram-variable bacilli, straight rods with blunt ends, boxcar
shape. Some strains are spore forming

Question 25

Clostridium perfringens growth requirements:

Answer 25

anerobic, grow best at 35–37 °C

Question 26

Clostridium perfringens colony morphology:

Answer 26

gray to grayish yellow, circular, dome-shaped, translucent, and
glossy, with a double zone of beta-hemolysis on anaerobic sheep blood agar

Question 27

Bacteroides fragilis biochemical reactions:

Answer 27

Nitrate reduction –
Urease –
Motility –
Growth on bile +
Reverse CAMP test +
Vancomycin R
Kanamycin R
Colistin R

Question 28

B. fragilis gram stain:

Answer 28

Gram-negative bacilli, pleomorphic with rounded ends — commonly resemble
a safety pin

Question 29

B. fragilis growth requirements:

Answer 29

anaerobic, grow best at 35–37 °C

Question 30

B. fragilis colony morphology:

Answer 30

convex, circular, white to gray, and translucent with no hemolysis on
anaerobic sheep blood agar. At 48 hours of growth, colonies are >1 mm, circular, and gray,
surrounded by a gray zone on Bacteroides bile esculin agar