Micro Ch 21

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  1. Describe the structure of the skin and mucous membranes and the ways pathogens can invade the skin
    • Epidermis
    • Keratin ( waterproof protein on epidermis)
    • Dermis

    Perspiration provides moisture and nutrients for growth - Salts in it inhibit growth 

    • Lysozyme break down bacterial cell walls
    • Sebum=acid
  2. Examples of normal skin microbiota
    State the general locations and ecological roles of its members
    Large numbers of gram positive cocci ( staphylococci, micrococci)

    • - Resistant to drying and high salt concentration 
    • -Areas with moisture have higher populations 

    • Locations: Gram + Diphtheroids 
    • - propiniobacterium acnes - hair follices 
    • -produce acids for low skin pH

    Corynebacterium xerosis occupy skin surface

    Yeast: Malassezia furfuf = cause dandruff
  3. Staphylococci from streptococci 
    - name infections caused by each
    -which one features the virulence factor M protein
    • Staphylococci: Gram + , form clusters, make coagulase ( clots blood) 
    • ex. 
    • negative strain: Staphylococcus epidermis( biofilm maker) 
    • -Staphylococcus aureus: MRSA
    • -Folliculitis, sty, furuncle, carbuncle, impetigo 
    • -Scalded skin syndrome: ( impetigo on new borns)
    • - Toxic shock syndrome 


    Streptococcal: Gram +, make hemolysins that lyse red blood cells, B-hemolytic cause disease 

    Ex. Group A Streptococci ( streptococcus pyogenes

    -- Use M proteins: external cell wall allows adherance and immune system avoidance 

    - Dissolve blood clots 

    • Ex. Erysipelas: infect dermal skin layer 
    •  Necrotizing Fascitis: flesh eating disease 

    Streptococcal toxic shock syndrome
  4. Causative agent, mode of transmission, and clinical symptoms of pseudomas dermatitis
    Superficial rash 

    Cause: Pseudomonas aeruginosa, enters by skin abrasion

    Mode : Swimming water/ hot tubs
  5. Cause, transmission, symptoms of otitis externa
    " swimmers ear" 

    Pseudomas aeruginosa

    Enters the ear, superficial infection of external ear canal 

    Swimming water transmission
  6. Acne cause, transmission, symptoms
    Propionibacterium acne 

    enters sebum channels

    Inflammatory lesions, accumulated sebum/ rupture hair follicle 

    Direct contact transmission
  7. Buruli ulcer 

    cause, mode ,
    Mycobacterium ulceran

    Enters the skin via break/insect , through contaminated water also 

    "leprosy"
  8. Cause, transmission  warts
    Papillomavirus : small skin growths 

    - transmitted via contact
  9. cause, transmission small pox (variola)
    • Orthopoxvirus 
    • 2 forms..
    • variola major and minor 

    Transmitted via respiratory route ( Air)  moves in the bloodstream and infects the skin 


    -- erradicated
  10. Monkey pox
    Respiratory tract ( contact with air from infected small mammals) 

    Pustules similar to small pox
  11. Chickenpox ( Varicella) / shingels ( Herpes Zoster)
    • chicken pox : Varicella-zoster virus 
    • -respiratory entry 
    • -vesicles face throat lower back 

    --also reyes syndrom( severe chicken pox) vomiting brain 

    • shingels : herpes zoster
    • -endogenous infection of peripheral nerves 
    • -vesicles typically on 1 side of waist, face, scalp
  12. Cold Sores
    • HSV 1: spread by oral/ respiratory
    • HSV 2: spread sexually 

    • tongue cheek inner lip 
    • UV light hormonal change 
    • skin contact
  13. Measles (rubeola)
    Transmitted respiratory 

    • Cold like symptoms, macular rash 
    • Koplik spots: red spots opposite of molars


    Pathogen: measles virus 

    transmission : aerosol
  14. Rubella
    German measles 

    cause: rubella virus

    Mild disease with a macular rash that looks like measles but less intense and goes away in 3 days 

    Transmit: respiraorty route 2-3 week incubation
  15. 5th disease
    ( Erythema infectiosum)

    - Human paravovirus B19 

    - mild flu, "slapped cheek: face rash
  16. Hand-foot-mouth disease
    • Enteroviruses
    • -spread via mucous /saliva

    • fever, sore throat
    • rash on hands feet mouth tongue
  17. Roseola
    Herpesvirus 6, 7 

    high fever, body rash, recovery within 1 to 2 days
  18. Cutaneous mycoses vs subcutaneous  mycoses
    • Cutaneous mycoses: fungal infection that colonize the hair nails and outer epidermis
    • also metabolize keratin 
    • Ex. trichophyton, microsporum, epidermphyton 
    • - dermatomycoses: ringworm
    • tinea pedis:  athletes foot 


    • Subcutaneous mycoses: more serious than cutaneous mycoses, penetrate the stratum corneum 
    • - usually caused by fungi that inhabit the soil 


    Ex. sporotrichosis ( enters wound-->ulcer)
  19. Cause of candidiasis
    • Yeast forms psydohyphae making it resistant to phagocytosis 
    • - In skin/ mucuous membranes of genitourinary tract and mouth 

    Ex. thrush 


    Happens when antibiotics suppress competing bacteria and the mucus pH changes
  20. Scabies
    • Caused by sarcopetes scabiei mites ( burrow in the skin and lay eggs)
    • - cause inflammatory skin lesions 
    • - transmitted via intimate contact
  21. Pediculosis ( lice)
    • Pediculus humanus capitis ( head louse) 
    • P.h corporis ( body louse) 

    • - feed on host blood 
    • -lay eggs on hair and attach to shaft 


    treatment: topical insecticides (permethrin/pyretheran)
  22. Ophthalmia neonatorum
    • Neisseria gonorrhoeae
    • Large amount of pus form, ulcers on cornea 

    - transmit to newborn during birth canal
  23. Inclusion conjunctivitis
    Chlamydia trachomatis 

    bacteria that grows as an obligate intracellular parasite 

    • - newborns eyes during birth
    • -swimming pool water
  24. Trachoma
    • Chlamydia trachomatis
    • -leading cause of worldwide blindness
    • -hand contact/flies transmitted 

    scaring on cornea/blindness
  25. Why have antibiotics almost entirely replaced the less expensive use of silver nitrate for preventing ophthalmia neonatorum
  26. herpetic keratitis
    • herpes simplex virus 1 ( HSV-1) 
    • infect cornea may cause blindess
  27. Acanthamoeba keratitis
    • Ameba transmitted via water/soil
    • Unsantiary contacts 

    Mild inflammation severe pain

Card Set Information

Author:
skoops
ID:
325801
Filename:
Micro Ch 21
Updated:
2016-11-19 01:33:55
Tags:
microbiology
Folders:
microbiology
Description:
Microbial disease of the skin and eyes
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