Bacterial I Lecture Review Flashcards by carolyn Ellis

Gram positive stain? why?

blue (crystal violet)

peptidoglycan in cell wall (no outer membrane)

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gram negative stain? why?

pink (safranin counterstain)

outer membrane with LPS

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beta hemolytic? alpha hemolytic?

beta: strep pyogenes (GAS)
alpha: strep pneumo

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catalase positive?

coagulase positive?

catalase: staph
coagulase: aureus

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CA-MRSA virulence factor

Panton-Valentine leukocidin

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CA-MRSA txt

clindamycin, bactrim +/- rifampin, minocycline, linezolid, vanco
mupirocin to nares
I&D abscesses <5cm, bleach, tea tree, BPO

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name for superficial folliculitis? name for deep folliculitis & folliculitis of beard?
mcc?

Bockhart’s impetigo
Sycosis, sycosis barbae
staph aureus

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risk of chlorhexidine

ototoxicity

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difference between furuncle and cabuncle

furuncle = acute, hair follicle only
carbuncle = collections of furuncles extending into subq, sinus tracts, possibly systemic sxs

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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

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botryomycosis mcc? presentation?

aka granular bacteriosis, bacterial pseudomycosi
staph aureus
nodular purulent lesions draining sulfure granules

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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

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pyomyositis cause? presentation? test?

s. aureus
abscess in deep muscles. tropics in children: thigh, immunocompromised in temperate: deltoid
test: MRI w/gadolinium

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MC bacterial infection in kids? cause?

impetigo contagiosa
staph aureus, then GAS (newborns - GBS)
strep w/ LAD

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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

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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

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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

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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

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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)