Microbiology: chapter 18 infectious diseases of the skin and eyes

Question 1

structure skin

Answer 1

-Epidermis
-Dermis
-subcutaneous layer

Question 2

Methicillin- resistant straphyloccocus aureus (MRSA)

Answer 2

-is a common cause of skin lesions in non hospitalized people.
-Even though the name mentions “methicillin,” these strains are usually resistant to multiple antibiotics.

Question 3

Staphylococcus aureus

Answer 3

-is a gram-positive coccus that grows in clusters, like a bunch of grapes. It is nonmotile
-Much of its destructiveness is due to its array of superantigens
-part of the normal biota in people

Question 4

Staphylococcus aureus can produce what?

Answer 4

Hemolysin postive, congulase postive

Question 5

Hemolysin postive

Answer 5

Can break down blood clots

Question 6

Congulase postive

Answer 6

Indicates the presence of S. aureus. (plasma will solidify partially or completely

Question 7

Other virulence:

Answer 7

streptokinase, hyaluronidase, lipases. (all enzymes that break down tissue)

Question 8

Impetigo:

Answer 8

-commonly seen in children

-is caused by strep and staph

-superficial bacterial infection that causes the skin to flake or peel off

Question 9

Necrotizing Fasciitis

Answer 9

-Strep and Staph most common to cause this

-produce enzymes that allow rapid spread

-include superantigens

-way down in the connective fascia, or way down in the tissue

Question 10

Staphylococcal scalded skin syndrome (SSSS):

Answer 10

-Cause by Staphylococcus aureus

-Although children and adults can be affected, SSSS develops predominantly in newborns and babies

-The phage-encoded exfoliative toxins A and B are responsible for the damage

-splitting with the epidermis-possible secondary infection

Question 11

Gas gangrene

Answer 11

-Caused by Clostridium perfringens

-Ischemia: are becomes anaerobic; necrosis (loss of oxygen)

-Gangrene: death of soft tissue due to loss of blood supply

Question 12

Clostridium pefringens:

Answer 12

-produces spores

-gas gangrene-gasses from fermentation

-enzymes degrade collagen and tissue

-enter bloodstream

(endospores in soil, on skin, intestines, vagina
Produce exotoxins under anaerobic conditions)

Question 13

Chickenpox and shingles:

Answer 13

-Caused by Human herpesvirus or (varicella-zoster virus)

-shingles will show up by the neuron branches

Question 14

Smallpox

Answer 14

-Caused by variola virus

-Two forms of smallpox
-variola major (20% mortality) and Variola minor (1% mortality)

-no animal reservoir for this disease

-smallpox no longer

-vaccine could be transported, could be given by a needle that could be dipped and put in the skin without a healthcare professional

Question 15

Hand/foot/mouth

Answer 15

-Caused Enteroviruses
-common in children under 5
-can have this with a fever
-no treatment

Question 16

Measles

Answer 16

-Highly contagious viral respiratory disease

-vaccine is 95% effective (herd immunity)

-Currently most concerning children (less than 1 year old)

-can cause fever

-In the developing world over 400 children die daily from measles

-newborn maternal antibodies

-measles are highly contagious before seeing symptoms

Question 17

Rubella (german measles):

Answer 17

-rare, less serious infection
-major concern to pregnant women
-baby can be blind, or even death

Question 18

Warts:

Answer 18

-caused by Human papillomavirus (50 plus types)
-to get rid of it kit from cvs
-can be transmitted, can be apart of normal flora

Question 19

Leishmaniasis:

Answer 19

-Leishmania donovani: visceral(guts)

-L. Tropica: cutaneous (lesions on the skin)

-L. Braziliensis- mucocutaneous (infects the face cause it loves moisture)
(transmitted by sand flies)

Not common in the united states

Question 20

Cutaneous Anthrax:

Answer 20

-direct contact with endospores

Question 21

Dermatophytes:

Answer 21

-Fungi that colonize hair, nails, and stratum corneum (tineas and ringworm)

Tinea capitis- scalp; head
Tinea cruris- groin
Tinea pedis- feet

Question 22

Candidiasis:

Answer 22

-oral candidiasis is called thrush
-seen in newborns

Question 23

Conjunctivitis:

Answer 23

inflammation of conjunctiva; pink eye

-Pink eye can be caused by viruses, bacterial infectious, and allergies

Question 24

Neonatal conjunctivitis:

Answer 24

bacterial and viral conjunctivitis

-often called Chlamydia, and gonera

Question 25

Trochoma

Answer 25

-low incidence in the U.S.

-major cause of blindness in parts of the world

-prevention: Hygiene, vector control, prompt treatment of initial infection

-transmission: indirect contact and mechanical vector

Question 26

Keratitis

Answer 26

-HSV-1&2
-HSV-1 oral herpes

-Acanthamoeba: common in tap water (reason why you don’t put contacts in tap water

-more serious eye infection than conjunctivitis.

Question 27

River blindness

Answer 27

-Caused by Wolbachia
-Helminth Onchocerca volvulus.
-Helminth (little worm)
-transmitted by black flies
-(release larvae that turn into worms)
-to prevent: reduce black flies and treatment