Infection of Skin, Soft Tissue, Muscle, and Associated Systems Flashcards
Is Staphylococcus aureus catalase positive or negative?
Positive
Is Streptococcus pyogenes catalase positive or negative?
Negative
S. pyogenes gram stain
Positive
What toxin causes scarlet fever?
Erythrogenic toxin
How do superantigens mediate their effects?
By binding to multiple types of T cell receptors and releasing an over abundance of cytokines
What is streptolysin?
Hemolysis enzyme produced by Streptococcus
What is streptokinase?
Enzyme that dissolves blood clots
What is a bulla indicative of?
Staph infection
What are carbuncle/furuncles indicative of?
Strep infection
How does strep manifest in the skin?
Erysipelas due to dermal lymphangitis erythema and induration (skin thickening/hardening); clear borders of rash
What does cellulitis involve?
The hypodermis
What do red streaks in cellulitis indicate?
Lymphangitis
What is lymphangitis?
Inflammation of the lymphatic channels in the skin
Which cellulitis infection is faster strep or staph?
Strep
What is necrotizing fasciitis?
Infection of muscles and fascia (typically Strep pyogenes)
Are clostridium gram positive or negative?
Positive
What does C. tetani cause?
Rigid paralysis
What does C. botulinum?
Flaccid paralysis
What does C. perfringens produce and what are it’s effects?
Lecithinase
Dissolves cell membranes
What is C. perfringens involved in?
Gas gangrene
What are genital warts called?
Condyloma
Which HPV strains are associated with cervical cancer?
16, 18, 31, 45
Which strains of HPV cause genital warts?
6, 11, 18, 31
What is the HPV genome?
dsDNA
Which genes in HPV genome are oncogenic?
E6
E7
What proteins are desmosomes associated with?
Cadherin
What proteins are hemidesmosomes associated with?
Integrins
What does viral replication require from host cells?
DNA replication enzymes
Transcription enzymes
What vaccine is more effective: Gardasil or Cervarix?
Gardasil
What is herpesviruses genome?
dsDNA viruses
Which herpes strand is roseola infantum?
Human Herpesvirus 6
What test is used to diagnose herpes?
Tzanck test
How can you distinguish between HSV 1 and 2?
PCR test
What is indicative of measles?
Koplick’s spots before rashes and maculopapules emerging
What type of virus is measles?
Paramyxovirus
What are Paramyxovirus genome?
ssRNA
What do Paramyxovirus use to enter cells?
Hemagglutin for recognition of cells and fusion protein for entry
What do Paramyxovirus create?
Multinucleate giant cells (syncytia) in lungs
What is togaviridae?
German measles (rubella)
Who is affected by German measles?
Fetus in the first three months of pregnancy
What does rubella cause?
Cataracts
Heart defects
What is the parvoviruses genome?
ssDNA
What does parvovirus B19 cause?
Erythem Infectiosum: slapped cheek syndrome, fever, infection of bone marrow
What are small discoloration of skin patches by fungi?
Pityriasis versicolor
What causes Pityriasis versicolor?
Malassezia furfur
How do you treat malassezia furfur?
Selenium sulphide or azole
What are three dermatophytes (ringworms)?
Epidermophyton, Trichophyton, and Microsporum
What type of skin can candida albicans infect?
Wet skin
What grow subcutaneously in nodules?
Sporothrix schenkii
typically found in farmers from thorns pricking
What are two systemic mycosis?
Blastomyces and Coccidioides