Pyogenic skin infections Flashcards
Infection of subq tissue with draining sinuses that is endogenous from mucus membrane that may present with lock jaw
Actinomycosis
Gram positive cocci arranged in clusters with positive catalase and coagulase tests
S aureus
Staphs with negative coagulase test
S epidermidis
S saprophyticus
Most common cause of localized pyogenic cutaneous infections
S aureus
Causes of impetigo
Streptococcus pyogenes
S aureus
Erythematous macule, vesicle, and pustule with ruptures leaving honey-colored crusts with lymphadenitis
Non-bullous impetigo
Superficial fragile serum-filled bullae on trunk and extremities
Bullous impetigo
Rapidly growing, gram-positive cocci in chains with beta-hemolytic colonies on blood agar
Streptococcus pyogenes
Positive bacitracin test of blood agar and negative catalase test
Streptococcus pyogenes
Complications of streptococcal pyogenes infection in a person with soft tissue infection
Streptococcal toxic shock syndrome
Complications in pts with prior streptococcal pharyngitis
Rheumatic fever
Glomerulonephritis
Exotoxins A and C of streptococcus pyogenes are related to what presentation
Scarlet fever
Exotoxin B of streptococcus pyogenes is related to what presentation
Necrotizing fasciitis
Hyaluronidase streptokinase produced by streptococcus pyogenes is related to what presentations
Erysipelas
Cellulitis
Key virulence factor of streptococcus pyogenes
M protein
Well demarcated, salmon red rash with pain, edema and erythema that is commonly on the legs
Erysipelas
Systemic manifestations in Erysipelas
Leukocytosis and lymphadenopathy
Chills and fever
Progression of erysipelas
Sepsis
Local necrosis of skin
Pathogens that cause cellulitis
S pyogenes
S aureus
Clostridium perfringens
Erysipelothrix rhusiopathiae
Vibrio vulnificus
Pasteurella mutocida
Pseudomonas
Main virulence factor of Clostridium perfringens
Alpha toxin/lecithinase
Effect of alpha toxin of Clostridium perfringens
Hemolytic, cytotoxic, and necrotic by degrading lecithin
Gram positive rods in pus without any inflammatory cells due to lysis
Clostridium perfringens
Treatment for gas gangrene
Penicillin
Clindamycin
Debridement
Amputation
Test for alpha toxin of Clostridium perfringens
Nagler reaction
Contaminates wounds caused during fishing, whaling, butchering, and in veterinarians
Erysipelothrix rhusiopathiae
Gram positive, filamentous, catalase negative bacilli
Erysipelothrix rhusiopathiae
Viral factors and their functions in Erysipelothrix rhusiopathiae
Neuraminadase –> penetrates epithelial cells
Capsule –> antiphagocytic
Erythematous violaceous rash on finger that proceeds to cellulitis and can lead to erysipeloid and septicemia
Cellulitis from Erysipelothrix rhusiopathiae
Treatment for Erysipelothrix rhusiopathiae cellulitis
Penicillin
Cephalosporins
Clindamycin
Fluoroquiniolones
Gram negative, curved rods. Oxidase positive and halophilic.
Vibrio vulnificus
Transmission of Vibrio vulnificus
Contact with marine shellfish
Symptoms of Vibrio vulnificus infection
Ecchymosis
Painful bullae
Cellulitis
Septicemia
Treatment for Vibrio vulnificus infection
Tetraclycin
Cefotaxime
Fluoroquinolones
Debdridement
Gram negative rods. Green pigmented colonies with fruity odor on culture. Oxidase positive.
Pseudomonas aeruginosa
Virulence factors of pseudomonas aeruginosa
Elastases
Exotoxin
Endotoxin
Capsule
Slime layer
Pathogen causing erythematous centrally necrotic lesions that rapidly progresses to sepsis and direct invasion and destruction of blood vessels
Pseudomonas aeruginosa
Ecthyma gangrenosum
Skin lesion with central necrosis and erythematous margins
Treatment of Pseudomonas aeruginosa infections
Cephalosporins
Carbapenems
Pharyngitis, strawberry tongue, flushed face, oral pallor, diffuse blanching rash
Scarlet fever after streptococcus pharyngitis
Rash with separation of epidermis diffusely due to loss of adhesion in young children
Staphylococcal scalded skin syndrome (SSSS)
Acute onset of fever, hypotension and multi-organ dysfunction with diffuse macular desquamating erythematous rash
Toxic shock syndrome
Virulence factor implicated in scalded skin syndrome
Exfoliative toxin