Microbiology Flashcards
list factors preventing skin infections
dry environment killing microorganisms
sebum contains fatty acids inhibiting bacterial growth
competitive bacterial flora
list some skin commensals
staph epidermidis
corynebacterium
propionibacterium
list the two most common pathogens causing infections in the skin
staph aureus
group A strep (strep pyogenes)
how do you diagnose skin infections
swab of lesion/pus sample
also blood cultures
what is the treatment for staph aureus infection
flucloxacillin
methicillin resistant staph aureus requires different treatment - what is this
vancomycin or doxycycline
what type of skin infections can staph aureus cause
boils infected cuts cellulitis impetigo wound infection
what is the most common type of fungal infection of the skin
tinea infection - ringworm
where are the following fungal infections located: 1 tinea capitis 2 tinea corporis 3 tinea manuum 4 tinea unguium 5 tinea cruris 6 tinea pedis
1 - scalp 2 - body 3 - hand 4 - nail 5 - groin 6 - feet (athletes foot)
what is the appearance of tinea infection
red circular rings which may overlap and cause itching - may scale and cause plaques
ringworm only affects keratinised tissues true/false
true
what organisms cause fungal infections of the skin
trichophyton rubrum
trichophyton mentagraphytes
what investigations are required for ringworm infection
woods light
skin scraping/nail clippings sent away in dermpak for microscopy and culture
what is the treatment for ringworm infection
small area of skin affected - topical clotrimazole or topical nail paint called amorolfine
extensive area/scalp affected - terbinafine orally
where is a candida skin infection most likely to occur
warm moist areas where the skin folds eg under the breast, groin and nappy areas in babies
what is the treatment of candida infection
clotrimazole cream and oral fluconazole
what is cellulitis and what organisms are most likely to cause it
acute infection of the skin and soft tissues, caused by beta-haemolytic strep and staph
describe the appearance of impetigo
well defined lesions on nose/lips area with honey coloured crusts on erythematous base - can cause blistering
who does impetigo usually affect
children aged 2-5 years old
candida infection in the mouth will wipe off with a spatula true/false
true - lichen planus will not
which virus causes chickenpox
varicella zoster virus
what is the presentation of chickenpox
widespread rash forming into vesicles then scabbing, inflamed skin with fever and itch
list some complications of chickenpox
secondary bacterial infection
pneumonitis
scarring
encephalitis
what are the precursors of severity with chickenpox
extremes of age - neonatal chickenpox if contracted in womb severe
depressed cell mediated immunity
what is shingles
reactivation of varicella zoster virus
describe the distribution of shingles
dermatomal
what is the presentation of shingles
tingling pain and erythematous vesicles which turn to crusts
pain is neuralgic in affected area
what is post herpetic neuralgia
neuralgia from shingles lasting more than 4 weeks
what are some complications of shingles
ramsay-hunt syndrome - vesicles and pain in auditory canal
facial palsy if CN VII affected
tinnitus, deafness and vertigo if CN VIII affected
who is the shingles vaccine routinely available for
over 70s
what is the initial presentation of herpes simples virus
primary gingivostomatitis - extensive red ulceration around the mouth lasting up to a week
what is the secondary presentation of herpes simples virus
cold sore - blistering rash around vermillion border
what type of lesions do HSV type 1 and 2 cause
type 1 - majority of oral lesions, half of genital lesions
type 2 - half of genital lesions and encephalitis in neonates
is aciclovir effective in treating HSV in active and latent disease
active yes but not latent disease
molluscum contagiosum is self-limiting but what can help remove lesions
local application of liquid nitrogen
which virus is the main cause of warts
human papilloma virus
list which types of HPV cause which conditions
type 1 - warts and veruccas
type 6 and 11 - genital warts
type 16 and 18 - cervical cancer
HPV vaccine is protective against which types of HPV
types 6, 11, 16 and 18
what is the treatment of a wart/verucca
topical application of salicylic acid
what causes hand, foot and mouth disease
enterovirus typically coxsackie virus
what causes slapped cheek disease
parvovirus B19
what is the presentation of slapped cheek disease
initially rash on the face with slapped cheek appearance
as the face changes get lacy macular rash on body
what non-dermatological manifestation of slapped cheek disease can affect adults
polyarthritis of the small joints
what investigations are carried out for slapped cheek disease
parvovirus B19 IgM antibody
list some complications of parvovirus
spontaneous abortion - foetal hydrops is precursor
aplastic crises
chronic anaemia
which animal does orf usually affect
sheep - known as scabby mouth disease
what is the presentation of orf
large, firm, fleshy nodule on typically farmers hand - usually self-limiting
what organism causes syphilis
bacterium cause treponema pallidum
how does primary syphilis present
chancre - painless ulcers at the site of entry usually mouth or genitalia
how does secondary syphilis present
red rash affecting whole of body esp palms and soles
how does tertiary syphilis present
CNS, CVS and gummatous involvement
what is the treatment for syphilis
injections of penicillin
what causes lyme disease
bacteria borrelia burgdorferi but ticks are a vector
what is the treatment for lyme disease
amoxicillin or doxycycline