23 - Skin Infections

  1. What are the three classes of Microbiota found on the skin?
    • Diptheroids
    • Staphyococci
    • Yeasts
  2. What are the characteristics of Diptheroids?
    • Gram Positve
    • Varied in Shape
    • Low Virulence
    • Body odor caused by bacterial breakdown of sweat
  3. What are the characteristics of Staphylococci?
    • Gram positive
    • Salt tolerant
    • Principle species on skin is Staphylococcus epidermidis
    • Prevents colonization of pathogenic flora
    • Maintains balance among microbial skin flora
  4. What are the characteristics of yeast (fungi)?
    • Tiny
    • Round or oval, but can be short rods
    • Causes rash, dandruff
    • Women have more yeast than men
  5. Symptoms - Small red bump or pimple stemming from hair follicle
    Agent - Stapylococcus Aureus
    Pathogenesis - Inflammation caused by
    accumulation of leukocytes, becomes a plug of cells and dead tissue, can
    spread to the heart, bones, brain
    Epidemiology - Found primarily in
    nostrils, transmission usually on the hands, shed large numbers of
    Prevention - Difficult
    Treatment - Furuncles and
    carbuncles need to be surgically drained, treatment complicated by
    antibiotic resistance
  6. What is a furuncle?
    • Sore stemming from folliculitis
    • Extended redness, tenderness swelling
    • Numerous furuncles lesions produce a carbuncle
  7. What is a carbuncle?
    Large areas of redness or swelling, stemming from furuncles caused by folliclulitis
  8. Symptoms - skin appears to be scalded, malaise, irritability, fever
    Agent - Staphylococcus aureus, RNA coded
    Pathogenesis - Caused by
    exfoliatins produced by S. aureus, split in epidermis, outer layer of
    skin lost, mortality rate 40%
    Epidemiology - Usually isolated, small
    outbreaks in nurseries
    Prevention - Patient isolation
    Treatment -
    Bacteriocidal antibiotics, removal of dead skin to prevent secondary
    Scalded Skin Syndrome
  9. Symptoms - Blisters, followed by yellow crusting, little fever or pain,
    lymph nodes enlarge near area
    Causative Agent - Streptococcus
    pyogenes, gram positive, beta hemolitic
    Pathogenesis - through
    scratches and minor injuries, bacterial surface components interfere
    with phagocytosis
    Epidemiology - 2 to 6 year olds living in tropical
    regions, usually spread person to person but also through insects and
    Prevention - Cleanliness and avoidance of people with
    Treatment - Penicillin and Erythromycin
    Streptococcal Impetigo
  10. Symptoms - Initially light pink spots on palms, wrists, ankles and soles
    of feet. Becomes raised bumps all over body. Shock or death can occur.
    Agent - Rickettsia rickettsii, obligate intracellular bacteria, gram
    negative, non-motile, coccobaccilus
    Pathogenesis - ticks infected
    with R. rickettsii
    Epidemiology - Zoonotic, US, Canada, Mexico, wood
    tick and dog tick
    Prevention - No vaccine, avoid tick infested areas,
    use DEET
    Treatment - Doxycyline and Chloramphenicol high effective
    Rocky Mountain Spotted Fever
  11. Symptoms - First stage, skin rash, chills, fever, headache, stiff neck,
    joint and muscle pain. Second stage, 2 - 8 weeks post rash, effects
    heart and nervous system. Third stage, arthritis, chronic nervous
    system may occur
    Causative Agent - Borrelia burgdorferi, large
    microaerophillic spirochete, linear genome, not circular
    - Bite of infected tick, host immunity supressed, enter bloodstream and
    spread to other parts of the body
    Epidemiology - Zoonotic, wide
    spread in US, black-legged in nymph stage main carrier
    Prevention -
    Avoid ticks, no vaccine
    Treatment - Antibiotics effective early, less
    effective in late stages
    Lyme Disease
  12. Symptoms - skin rash on back of head, face and mouth. Red spots called
    macules, small bumps called papuales, small blisters called vesicles,
    pus filled blisters called pustules. Can later become Shingles, herpes
    zoster, or reyes syndrome
    Causative Agent - Varicella-Zoster virus,
    medium sized, enveloped, double stranded DNA
    Pathogenesis - Enters
    through respiratory route, moves to skin via blood stream, cell mediated
    immunity T or B cells
    Epidemiology - Incidences have decreased,
    incubation period 1 to 2 days
    Prevention - attenuated vaccine, 12
    months and older
    Treatment - Treat symptoms, benadryl, calamine
  13. Symptoms - Begins with fever, funny nose, cough, red weepy eyes, rash
    appears within first few days, disappear within 1 week. Pneumonia and
    earache are common secondary infections
    Causative Agent - Rubeola
    virus, pleomorphic, medium sized, enveloped, single strand RNA
    - Respiratory route, spreads and replicates in lymph nodes, spreads to
    all parts of body. Has infected mucous, membranes have "Koplik spots",
    white spots can be seen in the back of throat.
    Epidemiology - Humans
    only natural host, spraed by respiratory droplets. Before vaccine, 99%
    infection rate.
    Prevention - MMR vaccination
    Treatment - no
    antiviral treatment
  14. Symptoms - slight fever with mild cold symptoms, enlarged lymph nodes
    behind ears and back of neck, faint facial rash, joint pain in adults
    Agent - Rubella Virus, member of togavirus family, small enveloped,
    single stranded RNA
    Pathogenesis - Respiratory route, causes
    sustained viremia
    Epidemilogy - Humans only natural host, 40% of
    infected people fail to develop symptoms
    Prevention - attenuated
    vaccine, 12 months, boostered at 4 to 6 years
    Treatment -
    German Measles (3 Day Measles)
  15. Common in children 6 months to 3 years
    Begins abruptly with high
    fever, after fever subsides, develops rash on chest and abdomen,
    vanishes in a few hours to days
    Children do not appear ill.
    by herpes type 6 virus
    No vaccine
    Treat symptoms
  16. Caused by Papillomavirus
    Can infect skin through minor abrasion
    nonenveloped, double stranded DNA
    Virus can survive on a number of
    inanimate objects
    Infects deeper cells of epidermis
    Incubation 2 -
    18 months
Card Set
23 - Skin Infections
23 - Skin Infections