BACTERIAL DISEASES OF HUMANS

1. BACTERIAL DISEASES OF HUMANS

2. AIRBORNE DISEASES

3. Diphtheria (Corynebacterium diphtheriae) organism: lysogenized by phage ? symptoms: exotoxin source: humans antitoxin therapy cutaneous diphtheria

5. Legionnaires' Disease (Legionella pneumophila) symptoms source: environment, water cooling towers, etc. treatment: erythromycin, rifampin prevention: chlorination of heating water 3-6% of nosocomial pneumonias

6. Bacterial Meningitis organisms Streptococcus pneumoniae (11% of children) Neisseria meningitidis (27% of children) Haemophilis influenzae (43% of children) respiratory secretions from carriers colonize nasopharynx: spread through bloodstream to meninges

7. Bacterial Meningitis: Symptoms respiratory illness or sore throat meningeal symptoms vomiting headache lethargy confusion stiffness in neck and back

8. Bacterial Meningitis: Diagnosis and Treatment Diagnosis gram stain culture of spinal fluid Treatment chloramphenicol, etc.

9. Streptococcal Diseases: Streptococcus pyogenes (group A ?-hemolytic) pathogenesis extracellular enzymes that break down host molecules streptokinases (dissolve fibrin clots) cytolysins, streptolysin O, S: kill leukocytes capsules, M-protein: retard phagocytosis

11. Streptococcal Diseases (2) asymptomatic carriers droplet transmission diagnosis: clinical observation, culture, serology treatment: penicillin, erythromycin

12. Cellulitis and Erysipelas cellulitis spreading infection of subcutaneous tissue erythema and edema erysipelas acute inflammation and infection of dermal layer of skin infants, over 30 with streptococcal sore throat may recur periodically at same site

13. S. pyogenes (knee effusion)

14. Poststreptococcal Disease glomerulonephritis kidney damage immune complexes school age children 80-90% spontaneous slow healing

15. Poststreptococcal Disease rheumatic fever heart valves, joints, subcutaneous tissues, central nervous system post strep throat 6-15 years of age more frequent in tropical countries

16. Streptococcal Pharyngitis stimulates inflammatory response plus lysis of erythrocytes and leukocytes exudate on tonsils symptoms fever malaise headache

17. Streptococcal Pharyngitis (2) self-limited: disappears within a week penicillin to shorten course of infection, reduce poststreptococcal disease

18. Scarlet Fever throat infection with toxin producing strain of group A strep strawberry tongue, other symptoms of strep throat droplets of saliva or nasal secretions incubation 2-4 days

20. Streptococcal Pneumonia (Streptococcus pneumoniae) endogenous infection: normal flora predisposing factors viral infections of respiratory tract physical injury to tract fluid accumulation alcoholism diabetes

22. Streptococcal Pneumonia: Pathogenesis rapid multiplication in alveolar spaces alveoli fill with blood cells, fluid and become inflamed sputum rust colored: blood in lungs onset abrupt: chills, hard labored breathing, chest pain

23. Streptococcal Pneumonia: Diagnosis & Treatment diagnosis: chest X-ray, quellung reaction, culture penicillin (if not resistant) Pneumovax

24. Tuberculosis (most Mycobacterium tuberculosis) most common among elderly malnourished alcoholic Native Americans immunocompromised respiratory transmission

27. Tuberculosis: Infectious Process bacteria grow in lungs surrounded by lymphocytes, macrophages, connective tissue: hypersensitivity reaction tubercle formation disease usually stops as this point: bacteria still alive at center of lesion

28. Tuberculosis: Infection Process may undergo caseation necrosis if calcifies becomes Ghon complex: shows on X-ray if liquifies forms air-filled tuberculous cavities: can disseminate (miliary TB, reactivation TB)

29. Tuberculosis: Symptoms & Diagnosis symptoms fever fatigue weight loss cough with sputum diagnosis Mantoux test culture chest X-ray

30. Tuberculosis: Treatment isoniazid streptomycin ethambutol rifampin two or more simultaneously

31. Whooping Cough (Bordetella pertussis) 2000-4000 cases annually in U.S. (10 deaths) respiratory transmission incubation 7-14 days

32. Whooping Cough (2) pertussis toxin responsible for symptoms increases sensitivity of tissue to histamine and serotonin increased lymphocyte response secretion of thick mucus impedes ciliary action

33. Whooping Cough: Stages of Infection catarrhal stage: resembles cold paroxysmal stage: characteristic cough convalescent (after 6 weeks): may take months

34. Whooping Cough: Diagnosis& Treatment diagnosis culture fluorescent AB: nasopharyngeal swabs serology treatment: erythromycin, tetracycline, chloramphenicol prevention with DPT vaccine

35. ARTHROPOD-BORNE DISEASES

36. Lyme Disease (Borrelia burgdorferi) natural hosts: deer and field mice transmitted by deer tick Ixodes dammini

37. B. burgdorferi

38. Lyme Disease: Symptoms initial symptoms expanding, ring-shaped localized red rash accompanied by flu-like symptoms malaise and fatigue fever chills

39. Lyme Disease: Symptoms weeks or months later neurological abnormalities heart inflammation arthritis years later: nerve demyelination (Alzheimer's or MS)

40. Lyme Disease: Diagnosis & Treatment diagnosis spirochetes in skin lesions culture of organism serology treatment: penicillin or tetracycline early in course of disease prevents complications

41. Plague (Yersinia pestis) ground squirrels and prairie dogs Black Death: subcutaneous hemorrhages bite of infected rat flea multiplies in blood and lymph, phagocytic cells

43. Plague: Symptoms subcutaneous hemorrhages fever buboes: enlarged lymph nodes death in 50-70% of untreated cases (toxemia) pneumonic plague: inhalation; 100% fatal

45. Plague: Diagnosis & Treatment diagnosis direct blood smears culture serology treatment: streptomycin, tetracycline.

46. DIRECT CONTACT DISEASE

49. Anthrax (Bacillus anthracis) cutaneous anthrax incubation: 1-15 days papule ulcerates to form eschar headache, fever, nausea fatal if invade bloodstream pulmonary: wool sorter's disease

50. Cutaneous Anthrax

51. Anthrax: Diagnosis & Treatment diagnosis direct microscopic exam culture serology therapy: penicillin G vaccination of cattle, occupations at risk

53. Gas Gangrene (Clostridium perfringens) found in soil, intestinal tracts hydrolytic enzymes collagenase Dnase hyaluronidase proteinases cytotoxins

54. Gas Gangrene: Pathology death of tissue: gangrene gas from fermentation of tissue components carbon dioxide hydrogen death from severe toxemia

55. Gas Gangrene: Diagnosis & Treatment diagnosis culture gram stains treatment wound debridement removal of dead and dying tissue antitoxins hyperbaric oxygen chambers penicillin

56. Gonorrhea (Neisseria gonorrhoeae) acute infectious sexually transmitted disease mucous membranes genitourinary tract eye rectum throat

57. Gonorrhea: Pathogenesis attachment by pili phagocytosed by epithelial cells may be intracellular in PMN's host tissue responds mast cells more PMN's plasma cells later replaced by fibrous tissue

58. N. gonorrhoeae (urethral swab)

59. Gonorrhea in Males incubation 2-8 days urethral discharge: yellow, creamy pus painful urination

60. Gonorrhea in Females symptoms in 7-21 days some vaginal discharge may be very mild symptoms pelvic inflammatory disease fallopian tubes, etc. 10-20% of infected females

61. Gonorrhea: Other Infections arthritis gonorrheal endocarditis pharynx ophthalmia neonatorum

62. Gonorrhea: Diagnosis & Treatment diagnosis gram stain (males) culture (transport medium necessary) treatment penicillin/ampicillin + probenecid tetracycline some pen resistant strains

63. Gonorrhea: Prevention condoms treating asymptomatic carriers patient education no long-lasting immunity

64. Staphylococcal Disease (Staphylococcus aureus) normal flora pyogenic coagulase: pathogenic strains golden pigment can cause severe chronic infections

65. Staphylococcal Disease: Source & Transmission source asymptomatic carrier patient with disease transmitted by hands, respiratory tract, fomites

67. S. aureus (wound)

68. Staphylococcal Disease in Compromised Patients pimples, impetigo boils and carbuncles wound infections, abscesses septicemia osteomyelitis endocarditis meningitis respiratory infections: pharyngitis, laryngitis, bronchitis, pneumonia

69. Staphylococcal Disease: Localized Abscess pathogenesis: many exotoxins, enzymes (plasmids) tissue necrosis coagulase cause fibrin wall to form liquefaction of necrotic tissue

70. Localized Abscess (2) spreads in direction of least resistance furuncle: large abscess around hair follicle carbuncle: around several hair follicles central necrotic lesions drains, eventually heals bacteria may spread in lymphatics and bloodstream

71. STAPHYLOCOCCAL DISEASE: OTHER INFECTIONS

72. Staphylococcal Disease: Impetigo staph and strep highly contagious in schoolchildren pustules later crust over

73. Staphylococcal Disease: Toxic Shock Syndrome toxin-1 production symptoms low blood pressure fever diarrhea extensive skin rash shedding of skin

74. Staphylococcal Disease: Scalded Skin Syndrome plasmid gene for exfoliatin epidermis peels off infants, children, neonatal nurseries

75. Staphylococcal Disease: Diagnosis & Treatment diagnosis culture and identification phage typing for epidemiology therapy: tested for antimicrobial susceptibility

76. Syphilis (Treponema pallidum) congenital: in utero sexually transmitted mucous membranes, breaks in skin migrates to regional lymph nodes disseminated throughout body not highly contagious: 1/10 for one contact

77. Syphilis: Stages of Infection primary incubation 10 days to 3 weeks chancre: small painless, reddened ulcer with hard ridge at infection site contact with chancre: disease transmission (contains spirochetes) 1/3 of cases chancre disappears, no further disease serology positive 80% of cases remaining cases: spirochete enters bloodstream

78. Syphilis: Stages of Infection secondary 2-10 weeks after primary lesion skin rash 100% of individuals positive serology also loss of patches of hair malaise fever rash lesions also infectious

79. Syphilis: Stages of Infection latent phase: not normally infectious except mother to child in utero

80. Syphilis: Stages of Infection tertiary after many years 40% of untreated individuals gummas: degenerative lesions skin bone nervous system: mental retardation, blindness, shuffle walk (tabes), insanity result of hypersensitivity reaction reduction of spirochetes in body

82. Syphilis: Diagnosis clinical history physical exam dark-field, immunofluorescent microscopy serological tests VDRL, etc. (reagin) antitreponemal antibody: FTA

83. Syphilis: Treatment early stages: penicillin later stages: longer time course no immunization, long lasting immunity control measures prompt and adequate treatment of new cases follow-up on contacts sexual hygiene condoms

84. Tetanus (Clostridium tetani) soil and large intestine low invasiveness: symptoms from exotoxin tetanospasmin (plasmid gene) inhibition of release of neurotransmitters from inhibitory synapses: tetany also tetanolysin: hemolysin aids in tissue destruction fatality rate 30-90%

85. Tetanus: Prevention active immunization with toxoids DPT immunization proper care of wounds contaminated with soil prophylaxis with antitoxin penicillin

86. Leprosy Hansen's disease: Mycobacterium leprae nine-banded armadillo animal model often in tropical countries exposure for long periods necessary: nasal secretions incubation 3-5 years (or longer)

87. Leprosy: Pathogenesis invades skin cells, peripheral nerves pigmented skin eruption spontaneous healing: cell-mediated immunity (3/4 of all infections) remainder develop leprosy

88. Leprosy: Tuberculoid (Neural) Leprosy mild, nonprogressive delayed-type hypersensitivity reaction to antigens on surface damaged nerves and regions of skin that have lost sensation: surrounded by border of nodules

89. Leprosy: Lepromatous (Progressive) Leprosy patients do not develop delayed hypersensitivity bacteria kill skin tissue progressive loss of facial features, fingers, toes, other structures disfiguring nodules over surface of the body nerves less damaged than tuberculoid leprosy

90. Leprosy: Diagnosis & Treatment acid fast bacilli in lesions leptomin skin test treatment dapsone rifampin clofazimine chemoprophylactic drugs to contacts

91. FOOD-BORNE AND WATERBORNE DISEASES

92. Mechanisms of Pathogenesis colonization and growth in intestine invade tissues of host secrete exotoxins ingestion of preformed exotoxin (enterotoxin): intoxication or food poisoning disruption of intestinal functioning nausea, vomiting, diarrhea

93. Botulism (Clostridium botulinum) canned food insufficiently heated to kill spores botulinum toxin produced after germination of spores prevents release of acetylcholine from synapse muscles do not contract flaccid paralysis

94. Botulism: Symptoms within two days of toxin ingestion blurred vision difficulty in swallowing and speaking muscle weakness nausea vomiting

95. Infant Botulism infants under 1 year ingested endospores germinate in intestine organisms multiply and produce exotoxin honey in formula

96. Infant Botulism (2) symptoms constipation listless generally weak feeds poorly death from respiratory failure

97. Botulism: Diagnosis & Treatment untreated: 1/3 will die of respiratory or cardiac failure treatment supportive care antitoxins diagnosis hemagglutination tests inoculation of mice with patient serum, stools or vomitus for toxigenicity

98. Gastroenteritis (Campylobacter jejuni) intestinal tract of birds and animals chickens turkeys cattle also in surface waters humans: contaminated food, water, anal-oral sexual activity 2 million cases per year

99. Campylobacter Gastroenteritis: Pathogenesis incubation 1-10 days invades intestinal epithelium causes inflammation exotoxin secretion antigenically similar to cholera toxin

100. Campylobacter Gastroenteritis: Symptoms diarrhea high fever severe inflammation of intestine along with ulceration bloody stools

101. Campylobacter Gastroenteritis: Diagnosis & Treatment diagnosis: culture on blood agar in high carbon dioxide treatment self-limiting supportive therapy erythromycin in severe cases recovery in 5-8 days

102. Salmonellosis (Salmonella spp.) 2000 serovars of Salmonella intestinal tracts of animals poultry eggs beef products 50,000 cases per year reported (may be as high as 2-3 million cases)

103. Salmonellosis incubation time 8-48 hours food infection: bacteria multiply and invade intestinal epithelium symptoms abdominal pain cramps diarrhea fever

104. Salmonellosis (2) last for 2-5 days one billion Salmonella per gram feces loss of fluid problem for children, elderly

105. Salmonellosis: Diagnosis & Treatment diagnosis: culture of organism from stool treatment: supportive prevention good sanitation wash cutting boards well (separate for meat and vegetables)

106. Staphylococcal Food Poisoning (Staphylococcus aureus) food intoxication ingestion of toxin produced in improperly stored food ham processed meats chicken salad pastries ice cream hollandaise sauce

107. Staphylococcal Food Poisoning (2) heat-stable enterotoxin: cannot taste symptoms severe abdominal pain diarrhea vomiting nausea onset 1-6 hours after ingestion last 24 hours or less

108. Staphylococcal Food Poisoning: Diagnosis & Treatment diagnosis: symptoms treatment: supportive

109. E. coli Gastroenterritis (Escherichia coli O157:H7) also known as enterohemorrhagic E. coli or EHEC sources of outbreaks meats: undercooked or raw hamburger (ground beef), game meat, dry-cured salami fruits and vegetables: alfalfa sprouts, unpasteurized fruit juices, lettuce dairy products, cheese curds, raw milk (Canada.)

110. E. coli Gastroenterritis: Pathogenesis exotoxins that cause severe damage to the lining of the intestine verotoxin (VT) shiga-like toxin closely related or identical to the toxin produced by Shigella

111. E. coli Gastroenterritis: Symptoms severe cramping (abdominal pain) diarrhea: initially watery but becomes grossly bloody occasionally vomiting fever is either low-grade or absent self-limited: lasts for an average of 8 days

112. E. coli Gastroenterritis: Complications children hemolytic uremic syndrome (HUS) renal failure hemolytic anemia Up to 15% of hemorrhagic colitis victims can lead to permanent loss of kidney function

113. E. coli Gastroenterritis: Complications (2) elderly thrombic thrombocytopenic purpura (TTP) HUS two other symptoms fever neurologic symptoms mortality rate in the elderly as high as 50%

114. E. coli Gastroenterritis: Diagnosis & Treatment culture from diarrheal stools tested stools directly for the presence of verotoxin isolation of E. coli of the same serotype from the incriminated food

115. Typhoid Fever Salmonella typhi contaminated food or water incubation 10-14 days pathogenesis colonize small intestine penetrate epithelium spread to lymphoid tissue, blood, liver, gallbladder

116. Typhoid Fever (2) symptoms fever headache abdominal pain anorexia malaise last several weeks carrier up to 3 months (except chronic carriers: gallbladder)

117. Typhoid Fever (3) diagnosis bacilli in blood, urine, stools serology: Widal test treatment: chloramphenicol, ampicillin recovery: permanent immunity

118. Typhoid Fever (4) prophylactic measures purification of drinking water pasteurization of milk prevention of food handling by carriers complete isolation of patients

121. SUMMARY