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TORTORA  FUNKE  CASE
ninth edition
MICROBIOLOGY
an introduction
21
Part A
Microbial
Diseases of the
Skin and Eyes
PowerPoint® Lecture Slide Presentation prepared by Christine L. Case
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Skin
 Salt inhibits microbes.
 Lysozyme hydrolyzes
peptidoglycan.
 Fatty acids inhibit some
pathogens.
 Defensins are
antimicrobial peptides.
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Figure 21.1
Mucous Membranes
 Line body cavities.
 Cells secrete mucus.
 Some cells have cilia.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Normal Microbiota of the Skin
 Gram-positive, salt-
tolerant bacteria
 Staphylococci
 Micrococci
 Diphtheroids
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14.1a
Microbial Diseases of the Skin
 Exanthem: Skin rash arising from another focus
of the infection.
 Enanthem: Mucous membrane rash arising from
another focus of the infection.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Microbial Diseases of the Skin
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 21.2
Staphylococcal Skin Infections
 Staphylococcus epidermidis
 Gram-positive cocci and coagulase-negative
 Staphylococcus aureus (golden colonies)
 Gram-positive cocci and coagulase-positive
 Leukocidin
 Exfoliative toxin
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Staphylococcal Biofilms
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Figure 21.3
Staphylococcus aureus
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Staphylococcus aureus
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Staphylococcal Skin Infections
 Folliculitis: Infections of the hair follicles.
 Sty: Folliculitis of an eyelash.
 Furuncle: Abscess; pus surrounded by inflamed tissue.
 Carbuncle: Inflammation of tissue under the skin.
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Furuncle (boil) and Carbuncle
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Staphylococcal Skin Infections
 Impetigo of the newborn
 Toxemia
 Scalded skin syndrome
 toxin caused
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 21.4
Streptococcal Skin Infections
 Streptococcus
pyogenes
 hemolytic
streptococci
 M proteins
 Prevent
complement &
phagocytosis
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 21.5
Streptococcal Skin Infections
 Erysipelas
 Impetigo
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Figures 21.6, 21.7
Invasive Group A Streptococcal Infections
 “flesh eating bacteria”
 Necrotizing fasciitis
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Figure 21.8
Infections by Pseudomonads
 Pseudomonas aeruginosa
 Gram-negative, aerobic rod
 Pseudomonas dermatitis
 “tub rash”
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Acne
 Comedonal acne occurs when sebum channels are
blocked with shed cells.
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Acne
 Inflammatory acne
 Propionibacterium acnes
 Gram-positive, anaerobic rod
 Treatment
 Preventing sebum formation (isotretinoin)
 Antibiotics
 Benzoyl peroxide to loosen clogged follicles
 Nodular cystic acne
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Inflammatory Acne
Nodular Cystic
Acne
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings