Microbiology of skin infections Flashcards
gram positive cocci in clusters
staph aureus
coagulase positive staph
staph aureus (golden colour)
is staph epidermidis coagulase positive or negative
negative
main cause of wound infections
staph aureus
gram positive cocci in chains
strep
what staph can cause UTI in women of child bearing age?
staph. saprophyticus
describe the classification of strep by haemolysis
beta- complete haemolysis
alpha- partial haemolysis
gamma- no haemolysis
what type of strep are the most aggressive?
group A and group B beta haemolytic strep
which strep group tend to cause sever skin and throat infections?
Group A
which strep group causes meningitis in neonates?
Group B
what are the 2 important alpha haemolytic strep?
strep. viridans
strep. pneumoniae
what is the most common cause of pneumonia
strep. pneumoniae
what are the main competitive bacterial flora of skin?
staph.epidermidis
corynebatcerium sp. (diptehroids)
proprionobacterrium sp.
can staph aureus cause impetigo?
yes
what infections can staph aureus cause?
impetigo cellutlitis boils infected eczema wound infection
what skin infections can strep pyogenes cause?
infected eczema impetigo cellulitis erysipelas -red on both cheeks necrotising fascitis
what type of strep is strep pyogenes
groups A beta haemolytic
how do you go about diagnosing skin infections?
swab of lesion
pus of tissue
blood cultures if deeper infection
how do you treat staph aureus infection?
flucloxacillin
how do you treat strep. pyogenes infection?
penicillin
+flucloxacillin
how do you treat necrotising fascititis?
surgical debridement and antibiotics
what is necrotising fascitits?
bacterial infection spreading below skin surface along fascial planes leading to rapid tissue destruction
causes severe pain!!
when should you swab leg ulcers/
only if cellulitis or other infection is present
what is the main underlying problem of leg ulcers?
vascular problem
tinea=?
ringworm
tinea capitis
scalp
tinea barbae
beard
tinea corporis
body
tinea pedis
feet (athletes foot)
tinea manuum
hand
describe the pathogensis of dermatophyte (ring worm)
fungus enter abraded or soggy skin
hyphae spread in stratum conreum
who is affected more by ringworm?
males.- foot and groin
scalp ringworm mainly affect children
main causal organism of ringworm?
trichophyton rubrum
how do you go about diagnosing skin infections?
clinical appearance
wood lights
skin scraping, nail clipping etc.- get microscopy and culture
how do you treat ringworm infections?
clotrimazole creamfor small areas of infected skin/nails
for scalp infections- terbinafine orally or intraconazole orally
how to treat candida
clotrimazole cream or oral fluconazole
what causes scabies?
sarcoptes scabei
where do you feel the itch in scabies?
finger webs, wrist and genital area
how do you treat scabies?
benzyl benzoate (adults only) malathion lotion, applied overnight to whole body
what is pediculus capitis
head lice
what is pediculus corporis?
body lice
what is phthirus pubis?
pubic louse
how to you treat lice
malathion
