Staphylococcal Infections: 11.14.2022. IS Questions

Question 1

Compare and contrast the typical microscopic morphology of Staphylococcus aureus and Streptococcus pyogenes

Answer 1

Staph: clusters of gram-positive cocci.

Strep: chains of gram-positive cocci

Question 2

What biochemical test can distinguish a Staphylococcus isolate from a Streptococcus species?

Answer 2

catalase test

Question 3

What biochemical test can distinguish a Staphylococcus aureus from a non-pathogenic Staphylococci?

Answer 3

coagulase test

Question 4

Name two diseases caused by Staphylococcus aureus

Answer 4

Food poisoning
Impetigo
TSS
Staphylococcal Scalded Skin Syndrome
Wound infections

Question 5

Name two diseases caused by Streptococcus pyogenes

Answer 5

Strep Throat
Scarlet Fever
Impetigo
TSS
Rheumatic Fever

Question 6

Name the two diseases caused by both Staphylococcus aureus and Streptococcus pyogenes (3 options)

Answer 6

Impetigo (pyoderma)
Toxic shock syndrome
Scalded skin syndrome

Question 7

What is the outermost layer of skin called?

Answer 7

epidermis

Question 8

Where are the sebaceous glands located in the skin?

Answer 8

dermis. near/on hair follicles.

Question 9

What do sebaceous glands produce?

Answer 9

an oily secretion called sebum

Question 10

What do bacteria on the skin use as sources of nutrients?

Answer 10

substances in sebum and sweat, such as lipids

Question 11

How can sweat make you smell?

Answer 11

odorless when first secreted, but bacteria degrade some of its components, producing foul-smelling compounds.

Question 12

Why do acne causing Propionibacteria live in hair follicles in oily parts of the skin?

Answer 12

they want to live within hair follicles, where O2 is limited, because they are obligate anaerobes.

Question 13

Where is the subcutaneous tissue located relative to the dermis?

Answer 13

deep to the dermis

Question 14

Name two infections of the upper respiratory tract. Which ones are viral infections and which ones are bacterial infections?

Answer 14

Conjunctivitis (pink eye): bacterial
Streptococcal Pharyngitis (strep throat): bacterial
Diphtheria: bacterial

Common cold: viral
Adenovirus Respiratory Tract Infections: viral

Question 15

What is pneumonia?

Answer 15

inflammation of the lungs accompanied by filling of the air sacs with fluids such as pus and blood

Question 16

How is pneumonia different from pneumonitis?

Answer 16

Pneumonitis: general term that refers to the inflammation of lung tissue.

So technically, pneumonia is a type of pneumonitis because the infection causes inflammation.

Pneumonitis is typically used by doctors to refer to noninfectious causes of lung inflammation

Question 17

What are viridans streptococci?

Answer 17

subclass of Streptococci. alpha-hemolytic streptococci that have a greenish discoloration.

Question 18

Which part of the respiratory system is sterile and has no normal flora?

Answer 18

lower respiratory tract

Question 19

Staphylococcus aureus:
- air needs?
- coagulase positive or negative? why is that significant?
- catalase positive or negative? what’s the equation?

Answer 19

• facultative anaerobe
• coagulase positive (used to differentiate from other Staph species)
• catalase positive (2H2O2 –> 2H2O + O2)

Question 20

Streptococcus pyogenes:
- air needs?
- catalase positive or negative?

Answer 20

• obligate fermenter
• catalase negative

Question 21

the upper respiratory tract consists of…?

Answer 21

nose and nasal cavity
pharynx (throat)
larynx (voice box)
epiglottis

Question 22

purpose of the catalase test?

Answer 22

distinguish G+ cocci from Staphylococci or Streptococci

Question 23

purpose of coagulase test?

Answer 23

distinguish between pathogenic and nonpathogenic Staphylococcus