Bacterial I Lecture Review Flashcards
Gram positive stain? why?
blue (crystal violet)
peptidoglycan in cell wall (no outer membrane)
gram negative stain? why?
pink (safranin counterstain)
outer membrane with LPS
beta hemolytic? alpha hemolytic?
beta: strep pyogenes (GAS)
alpha: strep pneumo
catalase positive?
coagulase positive?
catalase: staph
coagulase: aureus
CA-MRSA virulence factor
Panton-Valentine leukocidin
CA-MRSA txt
clindamycin, bactrim +/- rifampin, minocycline, linezolid, vanco
mupirocin to nares
I&D abscesses <5cm, bleach, tea tree, BPO
name for superficial folliculitis? name for deep folliculitis & folliculitis of beard?
mcc?
Bockhart’s impetigo
Sycosis, sycosis barbae
staph aureus
risk of chlorhexidine
ototoxicity
difference between furuncle and cabuncle
furuncle = acute, hair follicle only carbuncle = collections of furuncles extending into subq, sinus tracts, possibly systemic sxs
types of paronychia and characteristics?
cause?
acute abscess: s. aureus
acute erythema & swelling: strep pyogenes
chronic swelling: candida
cause: separation eponychium from plate from trauma
botryomycosis mcc? presentation?
aka granular bacteriosis, bacterial pseudomycosi
staph aureus
nodular purulent lesions draining sulfure granules
splendore-hoeppli phenomenon? DDx?
granule of non-filamentous bacteria in hyaline matrix with IgG and C3 = eosinophilic periphery wiht basophilic center = bunch of grapes actinomycosis mycetoma sarcoid botryomycosis sporotrichosis nocardia
pyomyositis cause? presentation? test?
s. aureus
abscess in deep muscles. tropics in children: thigh, immunocompromised in temperate: deltoid
test: MRI w/gadolinium
MC bacterial infection in kids? cause?
impetigo contagiosa
staph aureus, then GAS (newborns - GBS)
strep w/ LAD
acute glomerulonephritis cause? preceding infection? prognosis affected by abx?
group A beta-hemolytic strep M type 2
impetigo contagiosa, bullous impetigo, scarlet fever, perianal dermatitis (GAS)
prognosis not affected by abx
bullous impetigo cause? pathology? culture from lesion?
staph aureus group 2 phage type 71 or 55 –> exfoliative toxins A & B –> binds desmoglein 1
positive culture from blister
Staph Scalded Skin Syndrome other names? cause? culture? presentation?
Ritter’s ds, pemphigus neonatorum
children and renal failure pts: staph aureus group 2 phage type 55 & 71 exfoliative toxins A&B not cleared by kidneys + no immunity. binds dsg1
culture nasopharynx/conjunctiva. sterile bullae
erythema head to generalized, then flaccid bullae, facial edema. spares palms, soles, mucous membranes
Toxic Shock Syndrome cause? presentation? culture?
staph aureus exotoxin TSST-1 binds MHC class II –> cytokine release
acute febrile illness with scarlatiniform exanthem starts on trunk, strawberry tongue, erythema of palms and soles, desquamation 1-3 wks after onset. rapid progression to shock, organ involvement
negative cultures
Strep Toxic Shock Syndrome cause? presentation?
GAS M types 1 and 3 –> exotoxin A
adults 20-50 yo, portal of entry into skin –> superantigens bind to MHC II –> T cell cytokine release –> severe local pain +/- violaceous bullae –> shock, multi-organ failure, generalized erythema –> 30-60% mortality
ecthyma cause? presentation?
staph or strep pyoderma
shin or feet: vesiculopustule –> crust –> ulcer
urban, IVDA, HIV
pupura fulminans three forms
intravascular thrombosis and hemorrhagic infarction –> DIC
- neonatal: hereditary def protein C, protein S, antithrombin III
- idiopathic: follows febrile illness, def of protein S
- acute infectious: MCC. children after strep infection
scarlet fever cause? presentation? test?
GAS types A, B, C exotoxin –> delayed hypersensitivity rxn
1-10 yo’s
strep pharyngitis –> blanchable erythema at neck –> trunk & extremities –> sandpaper papules with skin fold accentuation
circumoral pallor, palatal petechiae, cervical LAD
palm&sole desquamation
ASO titer
schultz-carlton phenomenon
blanching erythema secondary to exotoxin in scarlet fever
erysipelas cause? location of infection?presentation?
mcc: GAS (gbs in newborns)
infection of dermis and superficial dermal lymphatics
erythema, induration, constitutional symptoms, leukocytosis >20
cellulitis mcc? location? presentation?
s. aureus & s. pyogenes, mixed in diabetics
deep dermal & SQ
portal of entry t. pedis
rubor, dolor, calor, tumor. no wbc. can have fever with prodrome
result of chronic cellulitis/erysipelas?
elephantiasis verrucosa nostras
recurrent lymphangitis and hypertrophic fibrosis
meleney’s gangrene
polymicrobial necrotizing fasciitis secondary to surgical trauma
three types of necrotizing fasciitis
type I: polymicrobial
type II: GAS
type III: gas gangrene/clostridial myonecrosis
GAS tense superficial blisters on volar fat pads
blistering distal dactylitis
strep intertrigo presentation? differentiation from candida?
well-demarcated fiery-red erythematous patches with pain and foul odor.
no satellite lesions
rheumatic fever diagnostic skin signs/major criteria? cause?
erythema marginatum (early) = patchy, polycyclic, evanescent erythema spreads peripherally
subcutaneous nodules (late)
also carditis, chorea, polyarthritis
strep
strep iniae
fish pathogen –> cellulitis of hands (tilapia, hawaiian sunfish)
fever, lymphangitis, cellulitis. PCN
erysipeloid of rosenbach cause? two types? presentation?
erysipelothrix rhusiopathiae (gram + rods)
fisherman, meat handlers (swine)
1. MC: localized purplish swelling of finger webs, spares phalanges
2. Generalized: fever, arthralgias, perifollicular papules –> violaceous plaques, endocarditis, septic arthritis
pneumococcal cellulitis presentation
strep pneumo
children w/ facial or periorbital edema & cellulitis with blue violaceous hue
fever, leukocytosis, septicemia
IVDA: extremity
anthrax cause? capsule? toxins? presentation? treatment?
woolsorter’s disease
bacillus anthracis (aerobic gram + spore forming rod)
polyglutamic acid capsule (inhibits phagocytosis)
edema toxin –> increased cAMP
lethal toxin –> TNF alpha and IL-1beta release
abx does not alter progression of cutaneous ds
vesicle –> ulcer –> eschar. nontender but suppurative adenitis
doxy or cipro. do not I&D
listeriosis presentation?
listeria monocytogenes (gram + bacillus)
eating cheese/dairy
skin: erythematous papules & pustules, LAD, fever
encephalitis/meningitis. neonates, pregnancy, alcoholics
cutaneous diphtheria organism? presentation? complications? what to do before treatment?
corynebacterium diphtheria (Klebs-Loeffler bacillus) gram + bacillus
punched out ulcer with rolled edges, pseudomembranous eschar on acral sites in tropics
complications: paralysis, cardiac ds
rule out hypersensitivity to horse serum via conjunctival test before txt
erythrasma cause? presentation? cause of coral red fluorescence?
corynebacterium minutissimum (gram + spore forming rod)
excessive growth in SC in humid environment –> pink brown scaling patches in intertriginous areas
coproporphyrin III causes coral-red w/ woods lamp
pitted keratolysis cause? pathophys? presentation? txt?
kytococcus sedentarius –> serine proteases K1 and K2 and sulfur compounds –> pits & odor
1-7 mm crater-like depressions in SC on weight bearing surfaces
BPO gel, erythromycin/clinda, antifungles, aluminum chloride
trichomycosis axillaris cause? presentation? txt?
corynebacterium tenuis
superficial bacterial infection of axillary/pubic hair w/ adherent yellow, red, black nodules on woods lamp
txt: shave, abx soap
gas gangrene cause? pathology? presentation?
clostridium perfringens (anaerobe)
membrane active toxins: alpha toxin & perfingolysin
infection of muscle with sudden onset shock, hemolytic anemia, leukocytosis, gas bubbles on palpation from hydrogen sulfide and CO2
tropical ulcer cause?
bacteriodes vincentii
desert sore cause?
corynebacterium diptheriae, staph, strep
grouped vesicles rupture –> ulcers covered by pseudomembrane
actinomyces israelii infection? txt?
anaerobic gram +, non-acid fast
dental procedures
lumpy jaw: nodules draining sulfure granules, may have underlying osteo
pcn
nocardia asteroides and norcadia brasilliensis presentations? 4 types? txt?
acid fast gram +
asteroides: MC disseminated in immunocomp
brasiliensis: MC primary cutaneous due to penetrating injury
4 forms: mycetoma, lymphocutaneous, superficial cutaneous, pulm/systemic
sulfa (bactrim)
