Skin

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Skin

  1. 1. Microbial Diseases of the Skin and Eyes<br />
  2. 2. Skin<br />Salt inhibits microbes.<br />Lysozyme hydrolyzes peptidoglycan.<br />Fatty acids inhibit some pathogens.<br />Defensins are antimicrobial peptides.<br />Figure 21.1<br />
  3. 3. Mucous Membranes<br />Line body cavities.<br />The epithelial cells are attached to an extracellular matrix.<br />Cells secrete mucus.<br />Some cells have cilia.<br />
  4. 4.
  5. 5.
  6. 6.
  7. 7. Normal Microbiota of the Skin<br />Gram-positive, salt-tolerant bacteria<br />Staphylococci<br />Micrococci<br />Diphtheroids<br />Malasseziafurfur<br />Figure 14.1a<br />
  8. 8. Microbial Diseases of the Skin<br />Exanthem: Skin rash arising from another focus of the infection.<br />Enanthem: Mucous membrane rash arising from another focus of the infection.<br />
  9. 9. Microbial Diseases of the Skin<br />Figure 21.2<br />
  10. 10. Staphylococcal Skin Infections<br />
  11. 11. Streptococcus<br />Staphylococcus<br />
  12. 12. Staphylococcal Biofilms<br />Figure 21.3<br />
  13. 13. S. aureus<br />Differential Characteristics<br />Coagulase<br />Fibrinogen  Fibrin<br />
  14. 14. Mannitol Salts Agar (MSA)<br />Staphylococcus aureus<br />
  15. 15. Staphylococcal Skin Infections<br />
  16. 16. Clinical Manifestations/Disease<br />SKIN<br /> folliculitis<br /> boils (furuncles)<br /> carbuncles<br />
  17. 17. Folliculitis<br />
  18. 18.
  19. 19. Furuncles (boil)<br />
  20. 20. Staphylococcal Skin Infections<br />
  21. 21. Clinical Manifestations/Disease<br /><ul><li>impetigo (bullous & pustular)
  22. 22. scalded skin syndrome
  23. 23. Neonates and </li></ul> children under 2years<br />
  24. 24. Impetigo<br />
  25. 25. Staphylococcal Skin Infections<br />Scalded skin syndrome<br />Bright red lesionsthat easily peels off in sheets<br />Exfoliative toxin<br />Antibiotic tx<br />Part of Toxic Shock Syndrome TSS<br />Figure 21.4<br />
  26. 26.
  27. 27. Staphylococcal scalded skin syndrom (SSSS)<br /><ul><li>Dermonecrotic toxin (exfoliative toxin)
  28. 28. Bullous exfoliative dermatitis</li></li></ul><li>Clinical Manifestations/Disease<br />Other infections<br />Primary staphylococcal pneumonia<br /> Food poisoning vs. foodborne disease<br /> Toxic shock syndrome<br />
  29. 29. Toxic shock syndrome<br /><ul><li>Toxic shock syndrome toxin (TSST-1)
  30. 30. Super antigen
  31. 31. Produced by 5-25% isolates
  32. 32. Tampon or infected wound
  33. 33. Fever
  34. 34. Rash
  35. 35. Exfoliation of skin
  36. 36. Shock (death rate 3%)</li></li></ul><li>Staphylococcal Skin Infections<br />
  37. 37. Metastatic Infections<br /><ul><li>Bacteremia
  38. 38. Osteomyelitis</li></ul>disease of growing bone<br />Pulmonary and cardiovascular infection<br />
  39. 39. Streptococcal Skin Infections<br />Streptococcus pyogenes<br />Group A beta-hemolytic streptococci<br />M proteins<br />Figure 21.5<br />
  40. 40.
  41. 41.
  42. 42.
  43. 43. Streptococcus pyogenes<br />Local infections<br />Impetigo<br />Erysipelas<br />Cellulitis<br />Necrotizing fasciitis (flesh-eating bacterium)<br />Systemic effect<br />Streptococcal toxic shock-like syndrome (STSS)<br />Spe (similar to TSS by S. aureus)<br />Scarlet fever (pyrogenic toxin by lysogenized )<br />Post-infection<br />Rheumatic fever (associated with pharyngitis)<br />Glomerulonephritis<br />
  44. 44. Invasive Group A Streptococcal Infections<br />M protein<br />Streptokinases<br />Hyaluronidase<br />Exotoxin A, <br />superantigen<br />Cellulitis<br />Necrotizing <br /> fasciitis<br />Figure 21.8<br />
  45. 45. Virulence factors<br />Adhesins<br />M protein (fibrillar Ag)<br />Fibronectin binding proteins (Protein F)<br />Lipoteichoic acid (LTA)<br />Hyaluronic acid capsule<br />Invasins<br />Streptolysins (S & O)<br />Hyaluronidase<br />Streptokinases <br />activates blood clot dissolving protein-plasminogen (human specific)<br />Dnase<br />Exotoxins<br />Pyrogenic (erythrogenic) toxin - Spe<br />Scarlet fever<br />Toxic shock syndrome<br />
  46. 46. Streptococcal Infections<br />
  47. 47. S. pyogenes<br />Necrotizing <br />fasciitis<br />Scarlet Fever<br />
  48. 48. Streptococcal Infections<br />
  49. 49. Streptococcal Skin Infections<br />Erysipelas<br />Impetigo<br />Figures 21.6, 21.7<br />
  50. 50. Erysipelas<br />NOTE:<br /><ul><li>erythema
  51. 51. bullae</li></li></ul><li>Erysipelas<br />Caused by group A streptococci, is characterized by raised, bright-red plaques with sharply defined borders.<br />
  52. 52. Cellulitis<br />
  53. 53. Pseudomonas Infections<br />
  54. 54. Infections by Pseudomonads<br />Pseudomonas aeruginosa<br />Gram-negative, aerobic rod<br />Pyocyanin produces a blue-green pus<br />Pseudomonas dermatitis<br />Otitis externa<br />Post-burn infections<br />
  55. 55. Pseudomonas Infections<br />
  56. 56. Acne<br />Comedonal acne occurs when sebum channels are blocked with shed cells.<br />Inflammatory acne<br />Propionibacterium acnes<br />Gram-positive, anaerobic rod<br />Treatment<br />Preventing sebum formation (isotretinoin)<br />Antibiotics<br />Benzoyl peroxide to loosen clogged follicles<br />Visible (blue) light (kills P. acnes)<br />
  57. 57. Propionibacterium Infections<br />
  58. 58.
  59. 59. Acne<br />Inflammatory acne (continued)<br />Nodular cystic acne<br />Treatment: isotretinoin<br />
  60. 60. Skin and other infections<br /><ul><li>Staphylococcus aureus
  61. 61. Skin, food poisoning, osteomyelitis, kidney abscess, endocarditis
  62. 62. Streptococcus pyogenes
  63. 63. Skin, pharyngitis and blood stream
  64. 64. Botulinum
  65. 65. Wound, food & infant
  66. 66. C. perfringens
  67. 67. Skin and diarrhea
  68. 68. Anthrax
  69. 69. Cutaneous, respiratory & GI</li></li></ul><li>Gas gangrene (Clostridium perfringens)<br />Alpha toxin (phospholipase C)<br />Zinc metallophospholipase<br />hemolysis and bleeding<br />Gas formation<br />Myonecrosis, shock, <br />renal failure and death<br />
  70. 70. ClostridialCellulitis<br />
  71. 71. NOTE:Large rectangular gram-positive bacilli<br />NOTE:Double zone of hemolysis<br />Inner beta-hemolysis = θ toxin Outer alpha-hemolysis = α toxin<br />Micro & Macroscopic C. perfringens<br />
  72. 72. Alpha toxin<br />Treatment<br />Debridement and excision<br />Antibiotics (prevent further spreading)<br />Hyperbaric oxygen therapy<br />Inhibit or kill the anaerobic bacteria<br />
  73. 73. Epidemiology of Bacillus anthracis<br /><ul><li>Rare in the US (1974-1990, 17 cases reported by CDC)
  74. 74. Enzootic in certain foreign countries (e.g., Turkey, Iran, Pakistan,and Sudan)
  75. 75. Anthrax spores infectious for decades
  76. 76. Biologic warfare experiments (annual tests for 20 years)
  77. 77. Three well-defined cycles
  78. 78. Survival of spores in the soil
  79. 79. Animal infection
  80. 80. Infection in humans</li></li></ul><li>Epidemiology of Bacillus anthracis(cont.)<br /><ul><li>Primarily a disease of herbivorous animals
  81. 81. Most commonly transmitted to humans by direct contact with animal products (e.g., wool and hair)
  82. 82. Also acquired via inhalation & ingestion
  83. 83. Increased mortality with these portals of entry</li></li></ul><li>Epidemiology of Bacillus anthracis(cont.)<br /><ul><li>Still poses a threat
  84. 84. Importing materials contaminated with spores from these countries (e.g., bones, hides, and other materials)
  85. 85. Usually encountered as an occupational disease
  86. 86. Veterinarians, agricultural workers</li></li></ul><li>Cutaneous Anthrax<br />Bacilllusanthracis<br />G+ and spore forming<br />Farm animals are major reservoir<br /> Inhalation, GI, cutaneous<br />Day 7<br />Day 4<br />Day 5<br />Day 12<br />
  87. 87. Cutaneous Anthrax<br />Bacilllusanthracis<br />G+ and spore forming<br />Farm animals are major reservoir<br /> Inhalation, GI, cutaneous<br />Virulence factors:<br /> Capsules<br /> Edema factor<br /> Lethal factor<br />Vaccine<br />Toxoid (protective antigen)<br /> Effective in short term but not long term<br />Day 4<br />Day 5<br />Day 7<br />Day 12<br />
  88. 88. Clinical Presentation of Anthrax<br /><ul><li>95% human cases are cutaneousinfections
  89. 89. 1 to 5 days after contact –
  90. 90. Small, pruritic, non-painful papule
  91. 91. hemorrhagic vesicle & ruptures
  92. 92. Slow-healing painless ulcer with black escharsurrounded by edema
  93. 93. Infection may spread -- Septicemia -- 20% mortality</li></li></ul><li>
  94. 94. Other Skin and Mucus Membrane Infections<br />Staphylococcus epidermidis<br />Catheters and prostheses<br />Vibriovulnificus<br />From shellfish and salt water<br />Obligate anaerobes (usually polymicrobic and foul smelling)<br />Puncture wounds<br />Deep wounds<br />Impaired blood supply<br />Gram negative bacteria<br />Decubitus ulcer (bed sores) <br />After intestinal “spill”<br />Pseudomonas aeruginosa<br />Catheters and prostheses<br />Burns and Surgical wounds<br />
  95. 95. VIRAL SKIN INFECTION<br />
  96. 96. Warts<br />Papillomaviruses<br />Treatment<br />Removal<br />Imiquimod (stimulates interferon production)<br />Interferon<br />
  97. 97. WART<br />
  98. 98. HPV and skin warts<br />(From Fields Virology, 4th ed, Knipe & Howley, eds, Lippincott Williams & Wilkins, 2001, Table 66-3.)<br />
  99. 99.
  100. 100.
  101. 101.
  102. 102.
  103. 103. Poxviruses<br />Smallpox (variola)<br />Smallpox virus (orthopox virus)<br />Variola major has 20% mortality<br />Variola minor has <1% mortality<br />Monkeypox<br />Prevention by smallpox vaccination<br />Figure 21.9<br />
  104. 104. SMALLPOX<br />
  105. 105. Distinguishing features of Smallpox from other rashes<br />Note in this slide that the density of the rash is greater on the face than on the body. <br />Pocks are usually present on the palms of the hands and on the soles of the feet.<br />
  106. 106. Monkeypox an emerging disease<br />
  107. 107. Monkeypox – an indigenous virus of equatorial Africa<br />Although not a virus of humans, the clinical symptoms are indistinguishable from smallpox. <br />Lethality is only slightly less than smallpox.<br />Although not as efficient as smallpox, Human to human transmission has been well documented<br />Monkeypox should perhaps be considered a bioterrorist agent<br />
  108. 108. In smallpox, fever is present for 2 to 4 days before the rash begins, while with chickenpox, fever and rash develop at the same time.All the pocks of the smallpox rash are in the same stage of development on any given part of the body and develop slowly. In chickenpox, the rash develops more rapidly, and vesicles, pustules, and scabs may be seen at the same time.<br />
  109. 109. Herpesviruses<br /><ul><li>Herpes simplex I & II (cold sores, genital herpes)
  110. 110. Varicella zoster (chicken pox, shingles)
  111. 111. Cytomegalovirus (microcephaly, infectious mono)
  112. 112. Epstein-Barr virus (mononucleosis,Burkitt’slymphoma)
  113. 113. Human herpesvirus 6 & 7 (Roseola)
  114. 114. Human herpesvirus 8 (Kaposi’s sarcoma)</li></li></ul><li>Herpesviruses<br />Varicella-zoster virus (human herpes virus 3)<br />Transmitted by the respiratory route<br />Causes pus-filled vesicles<br />Virus may remain latent in dorsal root ganglia<br />Figure 21.10a<br />
  115. 115. CHICKENPOX (VARICELLA)<br />
  116. 116.
  117. 117. Zoster<br />
  118. 118. Neonatal Varicella<br />
  119. 119. Varicella Vaccine<br /><ul><li>Prevents 40 - 70% of chickenpox occurrence
  120. 120. Greatly reduces the severity in the rest
  121. 121. Attenuated virus
  122. 122. Can still establish latency and reactivate</li></li></ul><li>SHINGLES (HERPES ZOSTER)<br />
  123. 123. Shingles<br />Reactivation of latent HHV-3 releases viruses that move along peripheral nerves to skin.<br />Figure 21.10b<br />
  124. 124.
  125. 125.
  126. 126. Zoster<br />
  127. 127.
  128. 128. Human Herpesviruses<br />Virus Subfamily Disease Site of Latency<br />Herpes Simplex Virus Ia Orofacial lesions Sensory Nerve Ganglia<br />Herpes Simplex Virus IIa Genital lesions Sensory Nerve Ganglia<br />Varicella Zoster Virusa Chicken Pox Sensory Nerve Ganglia<br />Recurs as Shingles<br />Cytomegalovirusb Microcephaly/Mono Lymphocytes<br />Human Herpesvirus 6b Roseola Infantum CD4 T cells<br />Human Herpesvirus 7b Roseola Infantum CD4T cells<br />Epstein-Barr Virus g Infectious Mono B lymphocytes, salivary<br />Human Herpesvirus 8g Kaposi’s Sarcoma Kaposi’s Sarcoma Tissue<br />
  129. 129. Herpes Simplex 1 and Herpes Simplex 2<br />Human herpes virus 1 and HHV-2<br />Cold sores or fever blisters (vesicles on lips)<br />Herpes gladiatorum (vesicles on skin)<br />Herpes whitlow (vesicles on fingers)<br />Herpes encephalitis (HHV-2 has up to a 70% fatality rate)<br />
  130. 130. Herpes Simplex 1 and Herpes Simplex 2<br />HHV-1 can remain latent in trigeminal nerve ganglia.<br />HHV-2 can remain latent in sacral nerve ganglia.<br />Acyclovir may lessen symptoms.<br />
  131. 131. Tissue tropism of HSV-1 and HSV-2<br />HSV-1:<br /><ul><li>Causes 95% of orofacial herpes (remainder caused by HSV-2)
  132. 132. Causes 10 - 30% of primary genital herpes (but seldom recurs there)</li></ul>HSV-2:<br /><ul><li>Causes primary and recurrent genital herpes infections
  133. 133. May cause primary oral herpes but, like HSV-1 in genital area, it seldom recurs there </li></li></ul><li>HERPES SIMPLEX INFECTION<br />
  134. 134. Cold Sores<br />
  135. 135.
  136. 136.
  137. 137. Eczema/Herpes<br />
  138. 138.
  139. 139. Herpes Simplex Virus type 2<br /><ul><li>Infects the genital tract
  140. 140. Is sexually transmitted
  141. 141. Complicates childbirth</li></li></ul><li>
  142. 142.
  143. 143. ROSEOLA<br />
  144. 144. Roseola<br />
  145. 145.
  146. 146. Measles (Rubeola)<br />Measles virus<br />Transmitted by respiratory route.<br />Macular rash and Koplik's spots.<br />Prevented by vaccination.<br />Encephalitis in 1 in 1,000 cases.<br />Subacute sclerosing panencephalitis in 1 in 1,000,000 cases.<br />Figure 21.14<br />
  147. 147. MEASLES (RUBEOLA)<br />
  148. 148. Measles induced syncytia<br />Formation of giant cells (syncytia) in measles pneumonia. Notice the eosinophilic inclusions in both the cytoplasm and nuclei. (From Schaechter’s Mechanisms of Microbial Disease; 4th ed.; Engleberg, DiRita & Dermody; Lippincott, Williams & Wilkins; 2007; Fig. 34-3)<br />
  149. 149. Measles pathogenesis<br />Mechanisms of spread of the measles virus within the body and the pathogenesis of measles. CMI, Cell-mediated immunity; CNS, central nervous system. (From Medical Microbiology, 5th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 59-3.)<br />
  150. 150. Measles time course<br />Time course of measles virus infection. Characteristic prodrome symptoms are cough, conjunctivitis, coryza, and photophobia (CCC and P), followed by the appearance of Koplik's spots and rash. SSPE, Subacute sclerosing panencephalitis. (From Medical Microbiology, 5th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 59-4.)<br />
  151. 151. Koplik’s spots<br />Koplik's spots in the mouth and exanthem. Koplik's spots usually precede the measles rash and may be seen for the first day or two after the rash appears. (Courtesy Dr. J.I. Pugh, St. Albans; from Emond RTD, Rowland HAK: A color atlas of infectious diseases, ed 3, London, 1995, Mosby.) (From Medical Microbiology, 5th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 59-5.)<br />
  152. 152. Measles rash<br />Measles rash. (From Habif TP: Clinical dermatology: Color guide to diagnosis and therapy, St Louis, 1985, Mosby.) (From Medical Microbiology, 5th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 59-6.)<br />
  153. 153. Rubella (German Measles)<br />Rubella virus<br />Macular rash and fever<br />Congenital rubella syndrome causes severe fetal damage.<br />Prevented by vaccination<br />Figure 21.15<br />
  154. 154. GERMAN MEASLES (RUBELLA)<br />
  155. 155. Rubella virus<br />Pathogenesis<br /><ul><li>respiratory transmission
  156. 156. replication in cytoplasm; budding
  157. 157. Viremia
  158. 158. Mild rash in adults; congenital rubella syndrome (CRS) after infection in first trimester when virus passes the placenta and infects fetus
  159. 159. CRS- deafness, blindness, mental retardation</li></li></ul><li>RUBELLAPATHOPHYSIOLOGY<br />Transmission is by respiratory droplets<br />Respiratory tract -->cervical lymph nodes-->hematogenous dissemination<br />Incubation period is 2 to 3 weeks<br />
  160. 160. RUBELLACLINICAL MANIFESTATIONS<br />Malaise<br />Headache<br />Myalgias and arthralgias<br />Post-auricular adenopathy<br />Conjunctivitis<br />NON-PRURITIC, ERYTHEMATOUS, MACULOPAPULAR RASH<br />
  161. 161. RUBELLACLINICAL MANIFESTATIONS<br />
  162. 162. RUBELLACLINICAL MANIFESTATIONS<br />
  163. 163. A 1905 list of skin rashes included (1)measles, (2)scarlet fever, (3)rubella, (4)Filatow-Dukes (mild scarlet fever), and<br />(5)Fifth Disease: Erythema infectiosum<br />Human parvovirus B19 produces milk flu-like symptoms and facial rash.<br />Roseola<br />Human herpesvirus 6 causes a high fever and rash, lasting for 1-2 days.<br />
  164. 164. Parvovirus<br />Structure<br />Small (5 kb) linear ssDNA genome, naked capsid<br />Pathogenesis<br />respiratory transmission<br />replication in nucleus, very host dependent, needs S phase cells or helper virus<br />viremia<br />antibody important in immunity<br />targets erythroid lineage cells; fifth disease (symptoms immunological); transient aplastic crisis; hydropsfetalis<br />Diagnosis<br />serology, viral nucleic acid<br />Treatment/prevention<br />none<br />
  165. 165. FIFTH DISEASE(ERYTHEMA INFECTIOSUM)<br />
  166. 166. Parvovirus pathogenesis<br />From Medical Microbiology, 5th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 56-3. <br />
  167. 167.
  168. 168. Parvovirus pathogenesis<br />A "slapped-cheek" appearance is typical of the rash for erythema infectiosum.(From Medical Microbiology, 5th ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 56-5.)<br />
  169. 169. PARVOVIRUSERYTHEMA INFECTIOSUM<br />
  170. 170. Coxsakie Viral infection<br />
  171. 171. Hand and mouth disease<br />
  172. 172. FUNGAL SKIN INFECTION<br />
  173. 173. Cutaneous Mycoses<br />Dermatomycoses: Tineas or ringworm<br />Metabolize keratin <br />Trichophyton:Infects hair, skin, and nails<br />Epidermophyton: Infects skin and nails<br />Microsporum: Infects hair and skin<br />Treatment<br />Oral griseofulvin<br />Topical miconazole<br />
  174. 174. Tinea<br />Ringworm (moth)<br />
  175. 175. RINGWORM (TINEA)<br />
  176. 176.
  177. 177.
  178. 178. Tinea corporis(the body)<br />
  179. 179. Tinea pedis(feet)<br />
  180. 180.
  181. 181. Tinea unguium(nails)<br />
  182. 182.
  183. 183. Tinea capitis(scalp)<br />
  184. 184.
  185. 185. Tinea cruris(jock itch)<br />
  186. 186.
  187. 187. Tinea barbae(bearded area)<br />
  188. 188.
  189. 189. Tinea versicolor<br />(Spaghetti and meatballs) <br />
  190. 190. Ecology of Dermatophytes<br />To determine the source of infection<br />Anthropophilic<br />Zoophilic<br />Geophilic<br />
  191. 191. Anthropophilic<br />Associated with humans only. Person -to-person transmission through contaminated objects (comb, hat, etc.)<br />
  192. 192. Zoophilic<br />Associated with animals. Direct transmission to humans by close contact with animals.<br />
  193. 193. Geophilic<br />Usually found in soil. Transmitted to humans by direct exposure.<br />
  194. 194. Geographic Distribution<br />Worldwide<br />
  195. 195. Dermatophytes3 Genera<br />Trichophyton<br />Microsporum<br />Epidermophyton<br />
  196. 196. Trichophyton(19 species)<br />Hair <br />Skin<br />Nails<br />
  197. 197. Trichophyton species<br />Large, smooth, thin wall, septate, pencil-shaped<br />
  198. 198.
  199. 199. Trichophytonrubrum<br />Causes a chronic infection in patients with a cell-mediated immune defect.<br />(most common in SC blacks)<br />
  200. 200.
  201. 201. Microsporum(13 species)<br />Skin<br />Hair<br />
  202. 202. Microsporum species<br />Thick wall, spindle shape, multicellular<br />
  203. 203. Microsporum canis<br />.<br />Most common etiologic agent of tinea in SC whites<br />
  204. 204. Epidermophytonfloccosum<br />Skin<br />Nails<br />
  205. 205. Epidermophyton floccosum<br />Bifurcated hyphae with multiple, smooth, club shaped macroconidia (2-4 cells)<br />
  206. 206. Therapy<br />Griseofulvin<br />Tinactin<br />Clotrimazole<br />Miconazole<br />Ketoconazole<br />Itraconazole<br />Terbinafine<br />
  207. 207.
  208. 208. Dermatophytid Reaction(ID)<br />Dermatophyte infection on feet<br /> (not clinically evident)<br /> Ringworm Lesion on hand<br /> (usually the dominant side)<br />
  209. 209. Dermatophytid Reaction(ID)<br />Culture skin scrapings from feet<br />Treat the tineapedis<br />The hand lesion (ID phenomenon) will respond to therapy of the foot.<br />
  210. 210. Dermatophyte Culture<br />
  211. 211. Cutaneous Mycoses<br />Figure 21.16<br />
  212. 212. Subcutaneous Mycoses<br />Sporotrichosis<br />Sporothrix schenckii enters puncture wound<br />Treated with KI<br />
  213. 213. SPOROTRICHOSIS<br />Primarily a disease of the cutaneous tissue and lymph nodes. Recently, pulmonary disease.<br />
  214. 214. SPOROTRICHOSIS<br />
  215. 215. PORTALS OF ENTRY<br /> Inhalation<br /> Inoculation<br />
  216. 216.
  217. 217. ECOLOGICAL ASSOCIATIONS<br /> Rose thorns<br /> Sphagnum moss<br /> Timbers<br /> Soil<br />
  218. 218. SPOROTRICHOSIS<br />
  219. 219.
  220. 220. Subcutaneous mycoses<br />Tineacorporis<br />Subcutaneous infections - produce chronic inflammatory disease of subcutaneous tissues and lymphatics. <br />sporotrichosis - ulcerated lesions at site of inoculation followed by multiple nodules - caused by a dimorphic fungus: Sporotrixschenckii.<br />
  221. 221. Daisies<br />
  222. 222. DRUGS OF CHOICE<br />CUTANEOUS OR SYSTEMIC FORM <br />Itraconazole<br />
  223. 223. Candidiasis<br />Candida albicans (yeast)<br />Candidiasis may result from suppression of competing bacteria by antibiotics.<br />Occurs in skin; mucous membranes of genitourinary tract and mouth.<br />Thrush is an infection of mucous membranes of mouth.<br />Topical treatment with miconazole or nystatin.<br />
  224. 224. CANDIDIASIS<br />
  225. 225. Candidiasis<br />Figure 21.17<br />
  226. 226.
  227. 227. Candidiasis<br />Thrush<br />Risk factors for candidiasis<br /> Post-operative status<br />Cytotoxic cancer Chemotherapy<br /> Antibiotic therapy<br /> Burns<br /> Drug abuse<br /> Gastrointestinal damage.<br />Cutaneous<br />
  228. 228. Chronic mucocutaneous candidiasis<br /><ul><li> given to a group of overlapping syndromes that have in common a clinical pattern of persistent, severe, and diffuse cutaneouscandidal infections.
  229. 229. These infections affect the skin, nails and mucous membranes. </li></li></ul><li>SCABIES & PEDICULOSIS<br />
  230. 230. Scabies<br />Sarcoptes scabiei burrows in the skin to lay eggs<br />Treatment with topical insecticides<br />Figure 21.18<br />
  231. 231.
  232. 232.
  233. 233.
  234. 234.
  235. 235. Pediculosis<br />Pediculus humanus capitis (head louse)<br />P. h. corporis (body louse)<br />Feed on blood.<br />Lay eggs (nits) on hair.<br />Treatment with topical insecticides.<br />Figure 21.19<br />
  236. 236.
  237. 237. Macular Rashes<br />A 9-year-old girl with a history of cough, conjunctivitis, and fever (38C) has a mcular rash that starts on her face and neck and is spreading to the rest of her body. Can you identify the cause of her symptoms<br />Measles<br />Rubella<br />Fifth disease<br />Roseola<br />Candidiasis<br />
  238. 238. BACTERIAL INFECTION<br />
  239. 239.
  240. 240.
  241. 241.
  242. 242. Bacterial Diseases of the Eye<br />Conjunctivitis (pinkeye)<br />Haemophilus influenzae<br />Various microbes<br />Associated with unsanitary contact lenses<br />Neonatal gonorrheal ophthalmia<br />Neisseria gonorrhoeae<br />Transmitted to a newborn's eyes during passage through the birth canal.<br />Prevented by treatment of a newborn's eyes with antibiotics<br />
  243. 243.
  244. 244.
  245. 245. BACTERIAL INFECTION<br />Chlamydia trachomatis<br />
  246. 246.
  247. 247.
  248. 248. Bacterial Diseases of the Eye<br />Chlamydia trachomatis<br />Inclusion conjunctivitis<br />Transmitted to a newborn's eyes during passage through the birth canal<br />Spread through swimming pool water<br />Treated with tetracycline<br />Trachoma<br />Leading cause of blindness worldwide<br />Infection causes permanent scarring; scars abrade the cornea leading to blindness<br />
  249. 249.
  250. 250. Figure 21.20a<br />Trachoma<br />
  251. 251.
  252. 252.
  253. 253. Viral Diseases of the Eye<br />Conjunctivitis<br />Adenoviruses<br />Herpetic keratitis<br />Herpes simplex virus 1 (HHV-1).<br />Infects cornea and may cause blindness<br />Treated with trifluridine<br />
  254. 254. VIRAL INFECTION<br />
  255. 255.
  256. 256.
  257. 257.
  258. 258. Protozoan Disease of the Eye<br />Acanthamoeba keratitis<br />Transmitted from water<br />Associated with unsanitary contact lenses<br />
  259. 259. PROTOZOAN INFECTION<br />
  260. 260.
  261. 261. Guinea worm<br />
  262. 262.
  263. 263.
  264. 264. 222<br />What is MRSA?<br />Easily transmitted and drug resistant, MRSA can survive on hands, clothing, environmental surfaces, and equipment.<br />About 126,000 hospitalized patients develop MRSA infections each year.<br />Over 5,000 of those patients die.<br />
  265. 265.
  266. 266. 224<br />More about MRSA<br />Staphylococcus aureus is commonly carried on healthy people’s skin, nares, and perineum.<br />It may cause superficial skin infections treatable with beta-lactam inhibitors (such as methicillin).<br />Over time, some strains have become resistant.<br />First cases of MRSA in the United States occurred in the 1960s.<br />Today, 46 out of 1,000 patients have MRSA.<br />
  267. 267.
  268. 268. 226<br />Controlling the spread of MRSA in a health care facility<br />Improve hand hygiene.<br />Make fastidious environmental cleaning and disinfection a priority.<br />Consider performing active surveillance cultures.<br />Identify colonized patients and implement contact precautions.<br />Implement and perform all interventions from the central line bundle and the ventilator bundle.<br />
  269. 269.
  270. 270. 228<br />Stopping antimicrobial drug resistance<br />Using antibiotics appropriately is key.<br />Encourage cultures before antibiotics are started, and, if necessary, narrow the spectrum of antibiotics based on culture results.<br />Review all culture reports to ensure that bacteria are sensitive to the prescribed antibiotics.<br />Teach the patient how to use antibiotics:<br />Take as prescribed<br />Finish the course of treatment<br />Don’t take someone else’s prescribed medication<br />
  271. 271. 229<br />Two types of MRSA<br />Community-associated MRSA (CA-MRSA)<br />Causes skin and soft-tissue infections, such as boils, blisters, abscesses, folliculitis, and carbuncles<br />Also, fever and local warmth, swelling, pain, and purulent drainage<br />Health care-associated MRSA<br />More highly drug resistant<br />Causes more invasive infections, such as surgical site infection, endocarditis, osteomyelitis, bacteremia, pneumonia<br />“According to the Centers for Disease Control and Prevention definition, a diagnosis of CA-MRSA requires that the patient have no medical history of MRSA or colonization and no risk factors associated with <br />health care–associated MRSA.”<br />
  272. 272. 230<br />MRSA transmission<br />CA-MRSA<br />Person-to-person by sharing personal items (clothing and towels) <br />Close contact<br />Health care-associated MRSA<br />Contaminated environmental surfaces<br />Staff members<br />

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