-
Microbes have tolerate to
Salt on skin
-
Stratum corneum
horny outer layer of the skin
-
Million of cells of the _______ _______ slough off daily, shedding microorganisms with them
stratum corneum
-
Defense: Antimicrobial peptides
positively charged chemicals disrupt the negatively charged membranes of bacteria
-
Defense: Sebum
- low pH makes the skin inhospitable to microorganisms
- toxic byproducts of fatty acids metabolism inhibit the growth of microorganism
-
Defense: Sweat
Inhibitory to microorganisms due to low pH and high salt concentration
-
Defense: Lysozyme
- Enzyme found in sweat, tears, and saliva
- specifically breaks down peptidoglycan found in cell wall of bacteria
-
Exanthem
- skin rash arising from another focus of the infection
- outside
- not skin to skin, has to inhale
- ex. chicken pox
-
Enanthem
- mucous membrane rash arising from another focus of the infection
- inside
- ex. kopliks spots associated with measle virus
-
Skin Lesion: Vesicle
fluid in socket, herpes, chicken pox
-
Skin lesion: Bulla
large blister
-
Skin lesion: Macule
- slightly raised, no fluid
- hive, measles
-
Skin lesion: Pustule
- Pus underneath deep skin
- boil, cystic acid
-
maculopapular
flat to slightly raised colored bumps
-
Most common skin disease in the world
Acne
-
Acne is a ________ _________ condition involving Propionibacterium acnes
chronic inflammatory
-
Staphylococcus epidermidis
- gram positive cocci
- coagulase negative (enzyme virulence, clumping of RBC)
-
Staphylococcus aureus
- Gram positive cocci
- Coagulase positive
-
Salt inhibits ____ ____ bacteria to grow
gram negative
-
Mannitol Salt Agar
salt content selects for Staphylococcus
-
Staphylococcus aureus
ferments sugar mannitol, and changes red agar to yellow
-
Staphylococcus epidermidis
no color change, but still grows staph, and no epidermidis
-
Folliculitis
infection of the hair follicles
-
Sty
folliculitis of an eye lash
-
Impetigo
- crusting (nonbullous) sores, spread by autoinoculation (scratching)
- usually stap aureus
- get by contact
- superficial bacterial infection that causes the skin to flake, peel
-
Furuncle
abscess; pus surrounded by inflamed tissue
-
Carbuncle
group of furuncles, inflammation of tissue under the skin
-
Toxic shock syndrome (TSS)
Toxic shock syndrome toxin 1
-
Scalded skin syndrome
exfoliative toxin A and B affects mostly newborns and babies
-
Methicillian Resistant Staphylococcus Aureus (MRSA)
any strain of S. aureus that has developed resistance to beta lactam antibiotics
-
MRSA espescially troublesome in ____ and ____ ____, where patients with open wounds, invasive devices, and weaken immune systems
hospitals, nursing homes
-
Streptococci
- blood agar for hemolysis
- A= no change
- B= see through agar
- C= greening partially, alpha hemolysis
-
Streptococcus pyogenes
- Group A beta-hemolytic streptococci
- Hemolysins
- Hyaluronidase
- Stretolysins
- M Proteins
- Cause strep throat, all virulence factors
-
Group A Streptococci
causes Necrotising fasciatis and strep, see zone of inhibition
-
Catalase test
- differentiate streptococci from non streptococci
- streptococcus does not react in this test
-
Catalase test
break down by products of aerobic respiration, bubbles positive for hydrogen peroxide
-
Erysipelas
not spread but painful
-
Necrotizing Fascists
Exotoxin A, super antigen spread
-
Nonbullous Lesions of impetigo
crusty, dry
-
Bullous impetigo
fluid inside
-
Viral infection of the skin-
Warts
-
-
Warts
- papillomaviruses
- over 100 different types
-
treatments for warts
- Removal: cryotherapy, electrodesiccation, salicylic acid
- Imiquimod: stimulates interferon production
- Bleomycin
-
Smallpox (variola)
- orthopox virus
- variola major has 20% mortality
- variola minor has less than 1% mortality
- Eradicated by vaccination
-
Monkeypox
prevention by smallpox vaccination
-
Chickenpox
- varicella-zoster virus (human herpesvirus 3)
- causes pus filled vesicles
- virus may remain latent in dorsal root ganglia
-
Chicken pox transmitted by
transmitted by respiratory route
-
Chicken pox prevention
live attenuated vaccine
-
Breakthrough varicella: chicken pox
in vaccinated people, still got it, need booster
-
Shingles:
- Reaction of latent HHV-3
- move along peripheral nerves to skin
- post herpetic neuralgia- damage nerves
- Acyclovir (all herpes) lessen symptoms
-
Shingles prevention
live attenuated vaccine
-
Herpes Simplex
Human herpesvirus 1 (HSV-1) and 2 (HSV-2)
-
Herpes Simplex: Cold sores or fever blisters
Vesicles on lips
-
Herpes Simplex: herpes gladiatorum
vesicles on skin
-
Herpes Simplex: Herpetic whitlow
vesicles on fingers
-
Herpes Simplex: Herpes encephalitis
central nervous system
-
HSV-1 can remain latent in where
trigeminal nerve ganglia
-
Human herpes simplex infections are
widespread and often recurrent
-
Herpesviradae
- simplexvirus
- varicellovirus
- roseoloviruse
- lymphocryptovirus
- rhadinovirus
-
-
Measles transmitted by
respiratory route
-
Measles prevented by
vaccination
-
Measles spot and rash
- Macular rash
- Kopliks spots
-
-
Rubella viruse
maculopapular rash and fever
-
Congenital rubella syndrome causes
severe fetal damage
-
Fifth disease (Erythema Infectiosum) produces
a mild rash
-
Fifth disease (Erythema Infectiosum) transmitted
respiratory droplets
-
Fifth disease (Erythema Infectiosum) (2)
Parvoviridae, parvovirus B19
-
Fifth disease (Erythema Infectiosum) symptoms
fiery red rash on cheeks, ears, and trunks. it appears within a few days
-
Fifth disease (Erythema Infectiosum) adults experience symptoms similar to those of
rheumatoid arthritis
-
Cutaneous Mycoses (4)
- Dermatomycoses
- pityriasis versicolor
- sportotrichosis
- candidiasis
-
Dermatomycoses
- fungi on skin
- also known as tinaes or ringworm
- metabolize keratin
-
Pitryriasis versicolor
endogenous skin infection that occurs in warm humid climates (yeast)
-
Sporotrichosis
- gardening, fungus in soil
- subcutaneous- go through skin in cut
-
Candidiasis albicans (yeast) may result from
suppression of competing bacteria by antibiotics
-
Candidiasis albicans (yeast) occurs in
skin and mucous membranes of genitourinary tract and mouth
-
Candidiasis albicans (yeast) treatment
topical treatment with miconazole or nystatin
-
Thrush
infection of mucous membrane of mouth
-
Parasites (4)
- Scabies
- chiggers
- pediculosis (lice)
- leishmaniasis
-
Scabies
Sarcoptes scabiei
-
Scabies ______ in the _____ to lay eggs
burrow, skin
-
scabies treatment
topical insecticide
-
Chiggers immature stages are
red harvest mite
-
Chiggers, ____ into ____ _____ and inject ________ ______ which ______ host cells
crawl, hair follicles, salivary fluid, dissolves
-
Pepdiculosis
- Lice
- pediculus humanus capitis
-
P. h. corporis
body louse
-
P. h. pubis
- Crabs
- feed on blood
- lay eggs (nits) on hair
- treatment with topical insecticides
-
Leishmaniasis
protozoan disease spread by the bite of the sandfly
-
Lacrimal Apparatus of the Eye
protect from dabre and infection
-
Bacterial eye infections involve
eyelid, cornea, and conjuctiva
-
three types of bacterial eye infection
- bacterial conjunctivitis
- trachoma
- keratitis
-
Keratitis
- invasion of deeper eye tissue
- blindness can result
- herpes simplex type 1 (HSV-1) or type 2 (HSV-2)
-
Trachoma
Chlamydia trachomatis
-
Trachoma spread through
- direct contact with infected eye, nose, or throat secretion
- contact with towels or clothes
- flies can spread bacteria
-
Viral and parasite eye infections involve the conjunctiva or cornea
- Viral pink eye
- Acute conjunctivitis
- Ochocerciasis
- River blindness
-
River blindness
- caused by onchocerca volvulus, a nematode, ringworm
- spread by bit of a black fly
- when the worm dies, the bacterial symbiot, Wolbachia is released which causes an immune response
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