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Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
Microbial Diseases of the Skin and Eyes
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Microbial Diseases of the Skin and Eyes

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Microbiology, an introduction. Basics microbiology, specially diseases caused by bacteries and virus

Microbiology, an introduction. Basics microbiology, specially diseases caused by bacteries and virus

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  • 1. Chapter 21 Microbial Diseases of the Skin and EyesCopyright © 2010 Pearson Education, Inc. Lectures prepared by Christine L. Case
  • 2. Q&A  How does the morphology of Candida albicans contribute to the microbe’s pathogenicity?Copyright © 2010 Pearson Education, Inc.
  • 3. Structure and Function of the SkinLearning Objective 21-1 Describe the structure of the skin and mucous membranes and the ways pathogens can invade the skin.Copyright © 2010 Pearson Education, Inc.
  • 4. The Structure of Human Skin Perspiration and sebum contain nutrients Salt inhibits microbes Lysozyme hydrolyzes peptidoglycan Fatty acids inhibit some pathogensCopyright © 2010 Pearson Education, Inc. Figure 21.1
  • 5. Mucous Membranes Line body cavities The epithelial cells are attached to an extracellular matrix Cells secrete mucus Often acidic Some cells have cilia In eyes, washed by tears with lysozymeCopyright © 2010 Pearson Education, Inc.
  • 6. Check Your Understanding The moisture provided by perspiration encourages microbial growth on the skin. What factors in perspiration discourage microbial growth? 21-1Copyright © 2010 Pearson Education, Inc.
  • 7. Normal Microbiota of the SkinLearning Objective 21-2 Provide examples of normal skin microbiota, and state the general locations and ecological roles of its members.Copyright © 2010 Pearson Education, Inc.
  • 8. Normal Microbiota of the Skin Gram-positive, salt-tolerant bacteria  Staphylococci  Micrococci  DiphtheroidsCopyright © 2010 Pearson Education, Inc. Figure 14.1a
  • 9. Normal Microbiota of the Skin Grow on oils Aerobes on surface  Corynebacterium xerosis Anaerobes in hair follicles  Propionibacterium acnes Yeast  Malassezia furfurCopyright © 2010 Pearson Education, Inc.
  • 10. Check Your Understanding Are skin bacteria more likely to be gram-positive or gram-negative? 21-2Copyright © 2010 Pearson Education, Inc.
  • 11. 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 infectionCopyright © 2010 Pearson Education, Inc.
  • 12. Skin LesionsCopyright © 2010 Pearson Education, Inc. Figure 21.2
  • 13. Bacterial Diseases of the SkinLearning Objectives21-3 Differentiate staphylococci from streptococci, and name several skin infections caused by each.21-4 List the causative agent, mode of transmission, and clinical symptoms of Pseudomonas dermatitis, otitis externa, acne, and Buruli ulcer.Copyright © 2010 Pearson Education, Inc.
  • 14. Staphylococcal Skin Infections Staphylococcus epidermidis  Gram-positive cocci, coagulase-negative Staphylococcus aureus  Gram-positive cocci, coagulase-positiveCopyright © 2010 Pearson Education, Inc. Clinical Focus, p. 593
  • 15. Staphylococcus aureus Antibiotic resistant Leukocidin Resists opsonization Survives in phagolysosome Lysozyme resistant Exfoliative toxin SuperantigenCopyright © 2010 Pearson Education, Inc. Clinical Focus, p. 593
  • 16. Staphylococcal BiofilmsCopyright © 2010 Pearson Education, Inc. Figure 21.3
  • 17. 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 Impetigo: crusting (nonbullous) sores, spread by autoinoculationCopyright © 2010 Pearson Education, Inc.
  • 18. Nonbullous Lesions of ImpetigoCopyright © 2010 Pearson Education, Inc. Figure 21.4
  • 19. Scalded Skin Syndrome Toxic shock syndrome (TSS)  Toxic shock syndrome toxin 1 Scalded skin syndrome  Bullous impetigo  Impetigo of the newbornCopyright © 2010 Pearson Education, Inc.
  • 20. Lesions of Skin SyndromeCopyright © 2010 Pearson Education, Inc. Figure 21.5
  • 21. Streptococcal Skin Infections Streptococcus pyogenes Group A beta-hemolytic streptococci Hemolysins Hyaluronidase Stretolysins M proteinsCopyright © 2010 Pearson Education, Inc.
  • 22. Group A Beta-Hemolytic StreptococciCopyright © 2010 Pearson Education, Inc. Figure 21.6
  • 23. Streptococcal Skin Infections Necrotizing fasciitis ErysipelasCopyright © 2010 Pearson Education, Inc. Figure 21.7
  • 24. Invasive Group A StreptococcalInfections Exotoxin A, superantigenCopyright © 2010 Pearson Education, Inc. Figure 21.8
  • 25. Streptococcal Toxic Shock Syndrome M proteins Complex with fibrinogen Binds to neutrophils Activates neutrophils Release of damaging enzymes Shock and organ damageCopyright © 2010 Pearson Education, Inc.
  • 26. Infections by Pseudomonads Pseudomonas aeruginosa  Gram-negative, aerobic rod  Pyocyanin produces a blue-green pus Pseudomonas dermatitis Otitis externa, or “swimmer’s ear” Post-burn infections OpportunisticCopyright © 2010 Pearson Education, Inc.
  • 27. Buruli Ulcer Caused by Mycobacterium ulcerans Deep, damaging ulcers Exceeds incidence of leprosyCopyright © 2010 Pearson Education, Inc.
  • 28. Classifications of Acne Comedonal (mild) acne Inflammatory (moderate) acne Nodular cystic (severe) acneCopyright © 2010 Pearson Education, Inc.
  • 29. Comedonal Acne Mild  Sebum channels blocked with shed cells Treatment  Topical agents  Salicyclic acid preparations  Retinoids  AdapaleneCopyright © 2010 Pearson Education, Inc.
  • 30. Inflammatory Acne Propionibacterium acnes  Gram-positive, anaerobic rod Treatment  Preventing sebum formation (isotretinoin)  Antibiotics  Benzoyl peroxide to loosen clogged follicles  Visible (blue) light (kills P. acnes)Copyright © 2010 Pearson Education, Inc.
  • 31. Nodular Cystic Acne Severe Treatment  IsotretinoinCopyright © 2010 Pearson Education, Inc. Figure 21.9
  • 32. Check Your Understanding Which bacterial species features the virulence factor M protein? 21-3 What is the common name for otitis externa? 21-4Copyright © 2010 Pearson Education, Inc.
  • 33. Viral Diseases of the SkinLearning Objective21-5 List the causative agent, mode of transmission, and clinical symptoms of these skin infections: warts, smallpox, monkeypox, chickenpox, shingles, cold sores, measles, rubella, fifth disease, and roseola.Copyright © 2010 Pearson Education, Inc.
  • 34. Warts Papillomaviruses  Treatment − Removal − Cryotherapy − Electrodesiccation − Salicylic acid − Imiquimod (stimulates interferon production) − BleomycinCopyright © 2010 Pearson Education, Inc.
  • 35. Poxviruses Smallpox (variola)  Smallpox virus (orthopox virus) − Variola major has 20% mortality − Variola minor has <1% mortality  Eradicated by vaccination Monkeypox  Prevention by smallpox vaccinationCopyright © 2010 Pearson Education, Inc.
  • 36. Smallpox LesionsCopyright © 2010 Pearson Education, Inc. Figure 21.10
  • 37. Chickenpox Varicella-zoster virus (human herpesvirus 3) Transmitted by the respiratory route Causes pus-filled vesicles Virus may remain latent in dorsal root ganglia Prevention: Live attenuated vaccine Breakthrough varicella in vaccinated peopleCopyright © 2010 Pearson Education, Inc.
  • 38. Copyright © 2010 Pearson Education, Inc. Figure 21.11a
  • 39. Shingles Reactivation of latent HHV-3 releases viruses that move along peripheral nerves to skin Postherpetic neuralgia Prevention: Live attenuated vaccine Acyclovir may lessen symptomsCopyright © 2010 Pearson Education, Inc.
  • 40. Copyright © 2010 Pearson Education, Inc. Figure 21.11b
  • 41. Herpes Simplex Human herpesvirus 1 (HSV-1) and 2 (HSV-2) Cold sores or fever blisters (vesicles on lips) Herpes gladiatorum (vesicles on skin) Herpetic whitlow (vesicles on fingers) Herpes encephalitis HSV-1 can remain latent in trigeminal nerve gangliaCopyright © 2010 Pearson Education, Inc.
  • 42. Cold Sores Caused by Herpes SimplexVirusCopyright © 2010 Pearson Education, Inc. Figure 21.12
  • 43. HSV-1 in the Trigeminal Nerve GanglionCopyright © 2010 Pearson Education, Inc. Figure 21.13
  • 44. Herpes Simplex HSV-2 can remain latent in sacral nerve ganglia HSV-2 encephalitis: 70% fatality Encephalitis treatment: AcyclovirCopyright © 2010 Pearson Education, Inc.
  • 45. Measles (Rubeola) Measles virus Transmitted by respiratory route Macular rash and Kopliks spots Prevented by vaccinationCopyright © 2010 Pearson Education, Inc. Figure 21.14
  • 46. Measles (Rubeola) Encephalitis in 1 in 1,000 cases Subacute sclerosing panencephalitis in 1 in 1,000,000 casesCopyright © 2010 Pearson Education, Inc.
  • 47. Reported U.S. Cases of Measles, 1960–2007Copyright © 2010 Pearson Education, Inc. Clinical Focus, p. 505
  • 48. Rubella (German Measles) Rubella virus Macular rash and fever Congenital rubella syndrome causes severe fetal damage Prevented by vaccinationCopyright © 2010 Pearson Education, Inc. Figure 21.15
  • 49. Fifth Disease Name derived from a 1905 list of skin rashes, which included  1. Measles  2. Scarlet fever  3. Rubella  4. Filatov Dukes disease (mild scarlet fever), and  5. Fifth disease, or erythema infectiosum − Human parvovirus B19 produces mild flu-like symptoms and facial rashCopyright © 2010 Pearson Education, Inc.
  • 50. Roseola Caused by human herpesvirus 6 (HHV-6) and 7 (HHV-7) High fever and rash lasting for 1–2 daysCopyright © 2010 Pearson Education, Inc.
  • 51. Check Your Understanding How did the odd designation of “fifth disease” arise? 21-5Copyright © 2010 Pearson Education, Inc.
  • 52. Diseases in Focus: Macular Rashes  A 4-year-old boy with a history of cough, conjunctivitis, and fever (38.3°C) now has a macular rash that starts on his face and neck and is spreading to the rest of his body.  Can you identify infections that could cause these symptoms?Copyright © 2010 Pearson Education, Inc.
  • 53. Diseases in Focus:Vesicular and Pustular Rashes  An 8-year-old boy has a rash consisting of vesicular lesions of 5 days’ duration on his neck and stomach. Within 5 days, 73 students in his elementary school had illness matching the case definition for this disease.  Can you identify infections that could cause these symptoms?Copyright © 2010 Pearson Education, Inc.
  • 54. Fungal Diseases of the Skin and NailsLearning Objectives21-6 Differentiate cutaneous from subcutaneous mycoses, and provide an example of each.21-7 List the causative agent and predisposing factors for candidiasis.Copyright © 2010 Pearson Education, Inc.
  • 55. Cutaneous Mycoses Dermatomycoses  Also known as tineas or ringworm  Metabolize keratinCopyright © 2010 Pearson Education, Inc.
  • 56. DermatomycosesCopyright © 2010 Pearson Education, Inc. Figure 21.16
  • 57. Cutaneous Mycoses Genera of fungi involved  Trichophyton: Infects hair, skin, and nails  Epidermophyton: Infects skin and nails  Microsporum: Infects hair and skin Treatment  Topical miconazole  Topical allylamineCopyright © 2010 Pearson Education, Inc.
  • 58. Cutaneous Mycoses Tinea unguium Treatment  Itraconazole  TerbinafineCopyright © 2010 Pearson Education, Inc.
  • 59. Subcutaneous Mycoses More serious than cutaneous mycoses Sporotrichosis  Most common U.S. disease of this type  Sporothrix schenchii enters puncture wound  Treated with potassium iodide (KI)Copyright © 2010 Pearson Education, Inc.
  • 60. Candidiasis Candida albicans (yeast) Candidiasis may result from suppression of competing bacteria by antibiotics Occurs in skin and mucous membranes of genitourinary tract and mouth Thrush: An infection of mucous membranes of mouth Topical treatment with miconazole or nystatinCopyright © 2010 Pearson Education, Inc.
  • 61. Candida albicansCopyright © 2010 Pearson Education, Inc. Figure 21.17a
  • 62. Case of Oral CandidiasisCopyright © 2010 Pearson Education, Inc. Figure 21.17b
  • 63. Systemic Candidiasis Fulminating disease can result in immunosuppressed individuals Treatment: FluconazoleCopyright © 2010 Pearson Education, Inc.
  • 64. Q&A  How does the morphology of Candida albicans contribute to the microbe’s pathogenicity?Copyright © 2010 Pearson Education, Inc.
  • 65. Check Your Understanding How do sporotrichosis and athlete’s foot differ? In what ways are they similar? 21-6 How might the use of penicillin result in a case of candidiasis? 21-7Copyright © 2010 Pearson Education, Inc.
  • 66. Parasitic Infestation of the SkinLearning Objective21-8 List the causative agent, mode of transmission, clinical symptoms, and treatment for scabies and pediculosis.Copyright © 2010 Pearson Education, Inc.
  • 67. Scabies Sarcoptes scabiei burrows in the skin to lay eggs Treatment with topical insecticidesCopyright © 2010 Pearson Education, Inc. Figure 21.18
  • 68. Pediculosis (Lice) Pediculus humanus capitis (head louse) P. h. corporis (body louse)  Feed on blood  Lay eggs (nits) on hair  Treatment with topical insecticidesCopyright © 2010 Pearson Education, Inc. Figure 21.19
  • 69. Check Your Understanding What diseases if any, are spread by head lice, such as Pediculus humanus capitis? 21-8Copyright © 2010 Pearson Education, Inc.
  • 70. Diseases in Focus:Patchy Redness and Pimple-Like Conditions  An 11-month-old boy came to clinic with a 1-week history of an itchy red rash under his arms. He seemed more bothered at night and had no fever.  Can you identify infections that could cause these symptoms?Copyright © 2010 Pearson Education, Inc.
  • 71. Microbial Diseases of the EyeLearning Objectives 21-9 Define conjunctivitis. 21-10 List the causative agent, mode of transmission, and clinical symptoms of these eye infections: ophthalmia neonatorum, inclusion conjunctivitis, trachoma. 21-11 List the causative agent, mode of transmission, and clinical symptoms of these eye infections: herpetic keratitis, Acanthamoeba keratitis.Copyright © 2010 Pearson Education, Inc.
  • 72. Bacterial Diseases of the Eye Conjunctivitis  An inflammation of the conjunctiva  Also called pinkeye or red eye  Commonly caused by Haemophilus influenzae  Various other microbes can also be the cause  Associated with unsanitary contact lensesCopyright © 2010 Pearson Education, Inc.
  • 73. Bacterial Diseases of the Eye Ophthalmia neonatorum  Caused by Neisseria gonorrhoeae  Transmitted to a newborns eyes during passage through the birth canal  Prevented by treating a newborns eyes with antibioticsCopyright © 2010 Pearson Education, Inc.
  • 74. Bacterial Diseases of the Eye Chlamydia trachomatis  Causes inclusion conjunctivitis, or chlamydial conjunctivitis  Transmitted to a newborns eyes during passage through the birth canal  Spread through swimming pool water  Treated with tetracyclineCopyright © 2010 Pearson Education, Inc.
  • 75. Bacterial Diseases of the Eye Chlamydia trachomatis  Causes trachoma  Leading cause of blindness worldwide  Infection causes permanent scarring; scars abrade the cornea leading to blindnessCopyright © 2010 Pearson Education, Inc.
  • 76. TrachomaCopyright © 2010 Pearson Education, Inc. Figure 21.20a
  • 77. TrachomaCopyright © 2010 Pearson Education, Inc. Figure 21.20b
  • 78. Other Infectious Diseases of the Eye Keratitis  Inflammation of the cornea  Bacteria (U.S.)  Fusarium and Aspergillus (Africa and Asia)Copyright © 2010 Pearson Education, Inc.
  • 79. Other Infectious Diseases of the Eye Herpetic keratitis  Caused by herpes simplex virus 1 (HSV-1).  Infects cornea and may cause blindness  Treated with trifluridineCopyright © 2010 Pearson Education, Inc.
  • 80. Other Infectious Diseases of the Eye Acanthamoeba keratitis  Transmitted via water  Associated with unsanitary contact lensesCopyright © 2010 Pearson Education, Inc.
  • 81. Check Your Understanding What is the common name of inclusion conjunctivitis? 21-9 Why have antibiotics almost entirely replaced the less expensive use of silver nitrate for preventing ophthalmia neonatorum? 21-10 Of the two eye diseases herpetic keratitis and Acanthamoeba keratitis, which is the more likely to be caused by an organism actively reproducing in saline solutions for contact lenses? 21-11Copyright © 2010 Pearson Education, Inc.
  • 82. Diseases in Focus:Microbial Diseases of the Eye  A 20-year-old man had eye redness with dried mucus crust in the morning. The condition resolved with topical antibiotic treatment.  Can you identify infections that could cause these symptoms?Copyright © 2010 Pearson Education, Inc.

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