Bacterial skin infections and dermatophytes Flashcards
Propionibacterium acnes
Gram-positive
Anaerobic, nonmotile, pleomorphic rod
Gram + coagulase + cocci
Staph aureus
What toxin is responsible for bullous impetigo?
exfoliation toxin (ET digests intracellular connections)
Cause of cellulitis
Pleomorph, HA SSTI (EMERGING INFECTION!!!)
Associated with previous trauma/surgery
Acinetobacter baumannii
Coccobacillus associated with cat or dog bite
Pasteurella multocida
Bacillus associated with FRESH water injuries
Aeromonas hydrophilia
Vibrio associated with SALT water injuries
Vibrio vulnificus
Causitive agent of myonecrosis is spore-forming, gram-positive anaerobic bacillus. What is it?
Clostridium perfringens type A
What is the VF found in CP type A? What is it responsible for?
Alpha-toxin = Phospholipase C
-Lyses RBCs, myocytes, fibroblasts, platelets, leukocytes
Crepitant skin, sweet mousy smell (cut hay), fever, tachycardia. Causitive agent? Key VF?
C. Perfringens, alpha toxin
What is the most common causitive agent of tinea capitis? Treatment of choice?
M. canis; Systemic griseofulvin
What are the most common causitive agents of t. pedis?
E. floccosum, T. mentgrophytes, and
T. rubrum
What does tinea unguium usually have involved as well?
systemic candida
What are the most common causitive agents of tinea cruris?
T. mentagrophytes, T. Rubrum, E. Floccosum, and M. Canis
Causitive agent of tinea versicolor? What does it look like microscopically?
Malassezia furfur; “spaghetti and meatballs”
Tx of tinea versicolor
Topical selenium sulfide, miconazole
Dimorphic species (yeast and mold) Can grow in saturated salt solutions. What is the causitive agent and what is the name of the infection?
Hortaea werneckii; tinea nigra
How is sarcoptes scabiei (mites) reproduced?
female is fertilized on the skin surface and burrows deep in skin, eggs will mature in skin and adult mites will appear in 2 weeks
When are symptoms of scabies more noticeable?
AT NIGHT
What population is crusted scabies found in? How is pediatric scabies different?
HIV infection; similar to crusted lesions except possibly blood filled
How do you ID scabies?
Mineral oil scrapings and microscopy
Pubic lice
Phithirus pubis
human lice. What is different about it?
pediculus humanus; LARGER than scabies and p. pubis
What can result from years of infestation with p. humanus?
“Vagabond’s disease” =darkened, thickened skin
