Cutaneous Microbiology and Immunology Flashcards
what are antimicrobial peptides important for
- innate immune mediators of skin
gram-positive bacteria predominate where on the skin
- dry areas
gram-negative bacterial predominate where on the skin
- moist areas
most bacteria are the in the superficial layers of the stratum ______ and in the upper parts of the ______-
- stratum corneum
- upper parts of hair follicles
what is the main aerobic bacterial resident of the skin
- staph epidermidis
what organisms colonizes normal skin in the nose, perineum, and vulva
- S. aureus
what organism is common on the skin of patients with atopic dermatitis
how does it occur?
- S. aureus
- reduce antimicrobial peptides
- chronic inflam allows bacterial and viral infection
what are G+, aerotolerant anaerobes prevalent in areas with sebaceous glands
- P. acnes (Propionibacterium spp.)
also known as Cutibacterium acnes
why are beta-hemolytic streptococci not common on normal skin
- inhibited by lipid
what is a cause of impetigo in kids
- group A strep
what are common inhabitants of the mouth that may rarely spread to the skin
- alpha hemolytic streptococci
S. viridians and S. pneumonia
fungi are found where
- under nails
what do keratinocytes have on them that allow them to contribute as an innate immune player
- toll like receptors (TLRs)
what do keratinocytes secrete that allow them to contribute as an innate immune player
- cytokines
- chemokine
what is the role of beta defenses and LL37
they are AMPs (Antimicrobial peptides)
- makes resistance difficult
- pokes holes in the membrane in irregular pattern
how does S. epidermis educate CD8+ T cells
- dendritic cells sample S. epidermiditis antigens
- present to CD8+ T cells
- induce IL17
- keratinocytes enhance barrier function and limit pathogen invasion
dysregulated innate immune responses in the skin result in what
- chronic cutaneous inflammation
more diverse skin flora correlate with _________
- disease remission
what do staphylococcus aureus and streptococcus pyogenes produce
- superantigens
- toxic shock toxins
how superantigen works
- binds outside of antigen specific pocket
- massive polyclonal expansion of T cells and “cytokine storm”
what does the exfoliative toxin of S. aureus cause
- scalded skin syndrome
role of S. aureus exotoxins
- cleave desmoglein causing intraepidermal splitting
how is S. aureus resistant to antimicrobial peptides
- binding and cleavage
- surface alteration mechanisms
superficial infections of dermatophytes are called
- ringworm
- tinea
fungal virulence factors include
- keratinases
- proteases
- lipases
predisposing factors for candida
- antibiotics
- steroid therapy
- diabetes and obesity
candida causes invasive, systemic infections in ___________ patients
- immunocompromised
which are the enveloped RNA viruses
- measles
- rubella
what are the noneveloped RNA viruses
- parvovirus B19
what does parvovirus B19 cause
- fifth disease
what are the enveloped DNA viruses
- HHV 6/7
- poxvirus
what virus causes warts
- HPV
what are the noneveloped DNA viruses
- papillomaviruses
what causes molluscum contagiosum
- poxvirus
describe papillomavirus
- small
- double stranded
- circular DNA genome
where does VZV reside
- latency in trigeminal and dorsal root ganglia
VZV reactivates along the _________ of the sensory nerve
- dermatome
which shingles vaccine is the live, attenuated virus
contraindicated for
- Zostavax
- immunocompromised
- pregnant
which shingles vaccine is the recombinant viral antigen + adjuvant
- shingrix
