Microbiology: A Systems Approach Chapter 18 Infectious Diseases Affecting the Skin and Eyes PowerPoint to accompany Cowan/Talaro Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 Chapter 18 Topics - Skin Defenses - Eye Defenses - Skin Diseases - Eye Diseases

3 Skin Defenses Skin Normal flora

4 Skin Epidermis –Stratum corneum (dead cells are sloughed off) Keratin (protein) –Waterproof the skin –Protects from microbial invasion –Replaced every days –No nerve endings or blood vessels

5 Skin continued Dermis –Source for epidermis cells –Connective tissue (fibers) –Nerves, blood vessels, lymphatic –Hair follicles, glands (sebum, lysozyme) Subcutaneous layer

6 The different layers of the skin are important defenses of the skin. Fig A cross-section of skin

7 Normal flora Survive dry and salty conditions Dense populations in the skin folds Types –Diphtheroids (Propionbacterium acnes) –Micrococci (Staphylococcus epidermis) –Yeast (Candida albicans)

8 Eye defenses Eye Normal flora

9 Eye Conjunctiva –Thin membrane that covers the eye, except the cornea –Secretes oil and mucous-containing fluids Best defense Cornea –Covers the iris –Several layers of epithelial cells –Epithelial cells can regenerate if damaged No lymphocytes, no inflammation –Immune privilege

10 The main parts of the eye that are important eye defenses. Fig The anatomy of the eye.

11 The best defense of the eye is the film of tears, which originates from the lacrimal apparatus of the eye. Fig The lacrimal apparatus of the eye.

12 Normal flora Very few present Resemble skin normal flora –Diphtheroids –Staphylococci –Micrococcus –Streptococci –Yeast

13 Skin Diseases Acne Impetigo Cellulitis Staphylococcal Scalded Skin Syndrome (SSSS) Gas gangrene Hansen’s Disease Skin rashes Warts Large skin lesions

14 Acne Bacterial infection Follicle-associated lesion Types –Comedo –Whitehead –Blackhead –Pustule –Cystic

15 Features of acne. Checkpoint 18.1 Acne

16 Impetigo Types –Staphylococcus aureus –Streptococcus pyogenes Peeling skin

17 An example of impetigo. Fig Impetigo lesions on the face

18 Staphylococcus aureus Associated with a number of diseases, including impetigo Enzymes –Coagulase –Hyaluronidase –Staphylokinase –Lipases Most study non-spore forming pathogen

19 Scanning Electron Micrograph (SEM) and colonies of Staphylococcus aureus, the causative agent of impetigo. Fig Staphylococcus aureus

20 A positive coagulase test is a primary method of identifying Staphylococcus aureus. Fig The coagulase test.

21 A miniturized test system for the identification of Staphylococcus. Fig Miniaturized test system used in further

22 Streptococcus pyogenes Associated with a number of disease, including impetigo Beta hemolytic M protein

23 Pathogenesis of S. pyogens involves the conversion of plasminogen to plasmin, which can degrade host tissue. Fig Plamin activation by S. pyogens

24 Features of impetigo caused by either Streptococcus pyogenes or Staphylococcus aureus. Checkpoint 18.2 Impetigo

25 Cellulitis Bacterial infection Fungal infection Infection of the dermis and subcutaneous tissues Lymphagitis Immunocompromised individuals are at risk

26 Features associated with cellulitis. Checkpoint 18.3 Cellulitis

27 SSSS Bacterial infection Affects mostly newborns and babies Bullous lesions Desquamation (lose of protetive keratinized layer)

28 Exofoliative toxin causes the major signs and symptoms of SSSS. Fig Staphylococcus scalded skin syndrome in a newborn

29 Features of SSSS or desquamation diseases. Checkpoint 18.4 Major Desquamation Diseases

30 Gas Gangrene Bacterial infection Anaerobic Toxins Gas formation Two forms –Localized –Diffused (myonecrosis)

31 An example of myonecrosis, where the necrosis has spread to other areas of the body. Fig The clinical appearance of myonecrosis in A compound fracture of the leg.

32 An example of the gas-filled spaces produced by Clostridium perfringens. Fig Growth of Clostridium perfringens

33 Features of gas gangrene. Checkpoint 18.5 Gas gangrene

34 Hansen’s Disease Bacterial infection Chronic and progressive Skin and nerve disease –Tuberculoid leprosy –Lepromatous leprosy (LL)

35 Tuberculoid leprosy is less severe, and can be treated effectively. Fig Leprosy lesions

36 LL is a more severe lesion, and is associated with disfigurement (lepromas). Fig A clinical picture of lepromatous leprosy.

37 Features of leprosy. Checkpoint 18.6 Leprosy

38 Skin rashes Vesicular or pustular rash diseases Maculopapular rash diseases

39 Vesicular rash diseases Elevated lesions filled with fluid Viral infection –Chickenpox –Smallpox

40 Chickenpox Common Benign Life-threatening for immunocompromised individuals Recuperation can result in Varicella- zoster virus infection –Reemerge as shingles (skin lesion)

41 Chicken pox reemerges as shingles, due to stress, X-ray treatments, drug therapy, or a developing malignancy. Fig Varicella-zoster virus reemergence as shingles/

42 Smallpox Eliminated due to world-wide vaccine program Very infectious viral disease (epidemic) Considered a bioterrorism agent

43 Examples of the rashes associated with chickenpox and smallpox in humans. Fig Images of chickenpox and small pox.

44 Features of chicken pox and small pox. Checkpoint 18.7 Vescular/pustular rash

45 Maculopapular rash diseases Flat to slightly raised colored bump –Measles or rubeola –Rubella –Fifth disease –Roseola

46 Measles Viral infection Vaccine available (MMR-measles, mumps, rubella), but disease still exists Koplik’s spots Exanthemum Complications – subacute sclerosing panencephalitis (SSPE) Syncytia formation

47 An example of the rash of measles. Fig The rash of measles.

48 Rubella Viral infection Vaccine available (MMR) Mild Serious for a fetus (teratogenic) –Disrupts fetus development

49 Fetal injury varies based on the time of infection. Fig An infant born with congenital rubella

50 Fifth disease Viral infection Erythema infectiosum Mild No vaccine

51 Roseola Viral infection Latent period – reactivates as mononucleosis-like or hepatitis-like symptoms Immunocompromised individuals are at risk

52 Features for measles, rubella, fifth disease, and roseola. Checkpoint 18.8 Maculopapular rach diseases

53 Warts Papillomas Molluscum contagiosum

54 Papillomas Viral infection Benign Nearly everyone is infected Different virus types –Plantar warts (HPV-1) –Flat warts (HPV-3,10,28,49)

55 Molluscum contagiosum Viral infection Distributed world-wide (endemic) Spread by contact Inclusion bodies contain viruses

56 Features of papillomas and molluscum contagiosum. Checkpoint 18.9 Wart and wart-like eruptions.

57 Large skin lesions Leishmaniasis Cutaneous anthrax Ringworm Superficial mycoses

58 Leichmaniasis Protozoan infection –Cutaneous –Mucocutaneous –Systemic Zoonosis No vaccine

59 Cutaneous anthrax Bacterial infection Endosporulation and germination Untreated cases can be fatal Vaccine available

60 Features of leishmaniasis and cutaneous anthrax. Checkpoint large pustula skin lesions

61 Ringworm Fungal infection (mycosis) –dermatophyte Conditions name – tinea –Scalp (tinea capitis) –Beard (tinea barbae) –Body (tinea corporis) –Groin (tinea cruris) –Foot (tinea pedis) –Hand (tinea poris) –Nail (tinea unguium)

62 An example of ringworm of the scalp. Fig Ringworm of the scalp.

63 An example of ringworm of the body. Fig Ringworm of the body.

64 An example of ringworm of the feet and fingernail. Fig Ringworm of the extremities

65 Fungal or dermatophyte spores associated with ringworm. Fig Examples of dermatophyte spores.

66 Superficial mycosis Fungal infection –yeast Cosmetic effects with no inflammation –Tinea versicolor

67 An example of tinea versicolor. Fig Tinea versicolor

68 Features of cutaneous and superficial mycoses. Checkpoint Cutaneous and superficial mycoses.

69 Eye Diseases Conjunctivitis Trachoma Keratitis River blindness

70 Conjunctivitis Bacterial infection Viral infection Neonates are at risk during birth Inflammation

71 An example of neonatal conjunctivitis. Fig Conjunctivitis

72 Features of neonatal, bacterial and viral conjunctivitis. Checkpoint Conjunctivitis

73 Trachoma Bacterial infection Endemic Pannus - inflammatory Blindness – chronic and secondary infections

74 An example of ocular trachoma. Fig Ocular trachoma.

75 Features of trachoma. Checkpoint Trachoma

76 Keratitis Viral infection Serious infection – complete corneal destruction

77 Features of keratitis. Checkpoint keratitis

78 River blindness Parasite infection –Parasite contains bacteria (mutualism) that contribute towards the infection Chronic Endemic

79 Features of river blindness. Checkpoint River blindness

80 Summary of diseases of the skin and eye. Taxanomic organization of microorganisms causing diseases of the skin and eyes.

81 Fig. 18.p573 Infectious Diseases Affecting the Skin and Eyes.