Skin & Eye Infections Flashcards
The skin is a ____ environment for microbial growth
poor
What are some reasons why its difficult for microbes to grow on the skin?
- Dry
- High salt concentration
- Sebum
- Secretes lysozyme
What is the mucous membrane?
The internal skin amde of epithelial cells attached to a basement membrane
What does the mucous membrane line?
Body cavities
____ cells secrete mucus
Goblet
What are the 4 types of lesions?
Vesicle, bulla, macule, pustule
Describe a vesicular lesion
- <1 cm
- Raised interstitial fluid
Describe a bullar lesion
- > 1cm
- Raised interstitial fluid
Describe a macular lesion
Flat red rash
Describe a pustular lesion
Pocket of pus deep in skin
What is impetigo?
Superficial skin infection often in newborns & young children
What can cause impetigo?
Staphylo & streptococci
What is blepharitis?
Inflammation & infection of the lid margins.
What is Toxic Shock Syndrome?
A life threating, systemic infection common in patients after surgery or IV abusers
What can cause Toxic Shock Syndrome?
S. aureus’ exotoxin TSST-1
S. pyogenes’ GAS
How do you treat Toxic Shock Syndrome?
IV antibiotic
What is Scalded Skin Syndrome?
Bacteria attack epidermal cell junctions + cause loosening (starts as a lesion)
What can cause Scalded Skin Syndrome?
S. aureus’ exfoliative toxin
How do you treat Scalded Skin Syndrome?
IV antibiotic
The eye surface is also known as the:
conjunctival surface.
List 3 bacteria considered normal flora in the eye.
- Micrococcus sp. (like S. epidermidis).
- Alpha-hemolytic streptococci.
- Diphtheroids (corynebacterium sp.).
The interior of the eye contains:
Sterile fluid.
What are some ways that the eye protects itself from infection? (2)
- Eyelid serves as a mechanical barrier to organisms.
2. Tears contain lysozyme & IgA, acting as a chemical barrier.
Warts on the skin are often caused by:
HPV (human papillomavirus).
What are 3 common staphylococcus bacteria?
S. aureus
S. epidermis
S. saprophyticus
What is keratitis?
Inflammation of the cornea.
What is the main difference between bacterial & viral keratitis?
Bacterial produces more pus than viral.
Which parasite can also cause eye infections?
Acanthamoeba sp.
Staphylococcus aureus infections often occur in the:
eyelids.
What is a stye?
When the eyelid glands/follicles become involved in an infection.
How do we treat styes?
Hot & cold compresses or antimicrobial eyedrops.
Trachoma is caused by the bacterium:
Chlamydia trachomatis A-C.
Where is trachoma found & how is it transmitted?
The tropics; vectors (flies).
Trachoma can lead to:
blindness.
What does hyaluronidase do?
Break down connective tissue
Differentiate between Chlamydia trachomatis A-C and Chlamydia trachomatis D-K/LGV.
C. trachomatis A-C causes trachoma (eye infection).
C. trachomatis D-K/LGV are genital chlamydia. When these organisms cause eye infections (rare), it is called inclusion conjunctivitis (not trachoma).
What kind of vaccine is the measles vaccine?
Live attenuated vaccine.
Ophthalmia neonatorum can cause _________ or spread to the vascular system, causing ________ _______ or _____.
blindness; systemic illness; death.
What do we do as a precautionary measure to prevent ophthalmia neonatorum?
Give newborns anitbiotic eyedrops.
Warts on the skin are often caused by:
HPV (human papillomavirus).
What is erysipelas?
Infection of dermal layer of skin
Describe the progression of erysipelas
Pharyngitis –> septicemia
How do you treat erysipelas?
Antibiotics
Describe staphylococcus sp.
G+, none-spore forming, non-motile, cocci in clusters
Describe streptococcus sp.
G+ cocci in chains
What are 3 common staphylococcus bacteria?
S. aureus
S. epidermis
S. saprophyticus
HSV-1 causes:
cold sores.
HSV-2 causes:
genital herpes.
HSV-3 causes:
chickenpox/shingles.
Herpes gladitorium is common in:
wrestlers.
Herpes whitlow is an occupational hazard of:
healthcare workers.
Measles is also known as:
rubeola.
What kind of virus causes measles?
Rubeola virus, an enveloped paramyxovirus (RNA).
What kind of rash does measles cuase?
Flat red rash (macular).
What species is measles’ natural host?
Humans.
Measles can cause blindness in children with _______ _ deficiency.
Vitamin A.
What are the 3 characteristic symptoms of measles?
Maculopapular rash: starts from behind the ears → face → upper arms → trunk → legs.
Respiratory symptoms (ex: tracheobronchitis & pneumonia).
Koplik’s spots (red, white & blue): appear on buccal mucosa.
Measles causes immunosuppression by:
infecting dendritic cells & monocytes to compromise antigen presenting activity.
What kind of vaccine is the measles vaccine?
Live attenuated vaccine.
S. auerus is a ____ pathogen
primary
What are some virulence factors of S. aureus?
- Coagulase
- Adhesion molecules
- Exotoxins + superantigens (MRSA & MSSA)
- Protein A
- DNase
S. epidermis is an ____ pathogen
opportunistic
S. saprophyticus is a ____ pathogen
primary
S. pyogenes is a group _ beta streptococcus sp.
A
S. agalactiae is a group _ beta streptococcus sp.
B
S. pyogenes has 2 post-infectious diseases which are:
- Acute glomerulonephritis
- Rheumatic fever
What makes S. pyogenes infectious?
GAS
What does streptokinase do?
Break down blood clots
What does hyaluronidase do?
Break down connective tissue
What can be found in normal flora of the skin?
- Staphylococcus epidermidis
- Other micrococci sp.
- Diphtheroids (aerobic: corynebacterium; anaerobic: propionibacterium)
- Some yeasts
5th disease is caused by what type of virus?
Non-enveloped DNA parvovirus.
What is the first noticeable symptom of 5th disease?
Pink lacy rash causing cheeks to become very red.
Describe the major complication of 5th disease.
TAC (transient aplastic crisis) in pregnant women: parvovirus invades & destroys RBCs in bone marrow, causing mother’s hemoglobin to drop significantly. The fetus will not be getting enough O2 from mother’s blood and will likely be stillborn/spontaneously aborted.
