Cutaneous Micro/Immuno Flashcards
normal flora dry vs wet skin
dry exposed: G+ mostly
wet occluded: G-
most in superficial layers of stratum corneum and upper hair follicle
main bacterial skin bugs (6)
staph epidermidis- aerobic
staph aureus- in nose, perineum and vulva, common in atopic derm
propionibacterium- aerotolerant, common in sebaceous glands (acne)
beta hemolytic strep not common on skin, inhibited by lipids
-cause impetigo in kids
alpha hemolytic strep common in mouth
G- are enterobacter, klebsiella, E coli- maybe normal flora
2 beta hemolytic
s pyogenes and agalactiae
2 alpha hemolytic
s viridans and pneumoniae
keratinocyte role in immunity
have TLRs
secrete cytokines and chemokines
antimicrobial peptides like Beta defensins and LL37
staph epi immune fn
“educates” CD8 T cells- antigens sampled by dendritic cells, presented to T cells and stim IL17
evokes response from keratinocytes w/ more barrier fn
changes in skin defense w/ atopic derm
less AMPs- more infection
more staph aureus than epi
chronic inflammation allows for infection
staph aureus toxins
exfoliative toxins:
- cause scalded skin syndrome
- exotoxins: non mitogenic, cleave desmoglein and cause intraepidermal splitting
3 non strep/staph infections on ddx w/ skin manifestations
rickettsia (RMSF)
neisseria meningitidis
treponema pallidum (syphilis)
most common dermatophytes
trichophyton rubrum
name of superficial dermatophyte infections
tinea modified by body site
aka ringworm
virulence factors of dermatophytes
keratinases, proteases, lipases
candida presences means..
colonizes normal skin
overgrowth causes infection w/ epithelial damage
predispoing factors to candida
antibiotics, steroid therapy, DM and obesity
can be more invasive and systemic in immunocompromisd
describe HPV
non enveloped DNA virus causes warts
