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27 Cards in this Set
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- Back
- 3rd side (hint)
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Koch's Postulates
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Organism is regularly found in lesions associated with a disease
Organism can be isolated in pure culture Inoculation of cultured organism causes disease in animal models Organism is recovered in lesions of infected animals |
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Skin
Barriers/Entry |
Barriers:
Dense keratinized outer layer Low pH Presence of fatty acids |
Entry:
Wounds Catheters, tubes, drains, etc. |
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Urogenital Tract
Barriers/Entry |
Urination flushes tract
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Entry:
Arise from ascension of perineal organisms Females>males, except at extremes of age Adhere to the urothelium Ascending infection to the kidneys |
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Respiratory Tract
Barriers/Entry |
Barriers:
Nasal hairs Mucociliary blanket Cough Alveolar phagocytic system |
Entry:
Bind to epithelia Paralyze cilia Break down mucus Resist phagocytic killing |
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Intestinal Tract
Barriers/Entry |
Barriers:
Gastric acidity Viscous mucus layer Lytic pancreatic enzymes and bile salts IgA Abs Commensal bacterial population of colon |
Usually transmitted by contaminated water or food
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Dissemination of Microbes
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Remain on surface +/- proliferation
Invade by motility and/or lysis Spread by: -contiguous surfaces -tissue planes -lymphatics/blood stream -axonal transport -placenta --> fetus |
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Mechanisms of Microbial Damage
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Directly through cell contact or invasion
Indirectly through secretion of toxins or enzymes Indirectly through induction of host cellular immune response |
Direct/indirect
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Mechanisms of Host Response Damage
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Suppuration - pus and space it occupies causes necrosis
Chronic inflammation - damage results from fibrosis and scarring Granulomatous inflammation - damage is from necrosis, mineralization and scarring Necrosis w/out inflammation - apoptosis due to immune response to certain viruses |
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Acute Suppurative Inflammation Organisms
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Most commonly assoc. with acute or cintinuing injury by extracellular microbes
Results in: 1. increased vascular permeability 2. leukocytic infiltration, mostly neutrophils 3. massing of neutrophils, formation of pus 4. destruction depends on organism and site of infection |
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Var. of Acute Inflam.
Hemorrhagic due to direct vascular damage |
Hantavirus
enterohemorrhagic E. coli |
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Var. of Acute Inflam.
Serous |
viruses
rickettsiae |
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Var. of Acute Inflam.
Fibrinous |
viruses
pneumococcal lobar pneumonia nocardiosis |
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Var. of Acute Inflam.
Necrotizing due to toxins |
anthrax (B. anthracis)
gas gangrene (C. perfringens) |
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Chronic Nonspecific Mononuclear Inflammation
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Response to viruses, intracellular bacteria, spirochetes, intracellular parasites, helminths
Focal or dispersed collections of lymphocytes, plasma cells, macrophages with granulation tissue |
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Chronic Granulomatous Inflammation
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Obligate intracellular organisms:
Mycobacteria Certain Fungi - Histoplama Certain parasites - Schistosoma |
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Acellular Inflammation
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Exudate with little to no inflammation
Profoundly immunocompromised host and rapidly advancing infections Maybe very superficial infections |
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Cytopathic - Cytoproliferative Inflammation
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Viral replication within cells = nuclear/cytoplamsic inclusions: CMV, rabies
Viral-induced fusion = syncytia: RSV, VZV, HSV Epithelial hyperplasia: poxvirus of molluscum contagiosum Dysplastic changes and neoplasia: HPV in epithelial cells, EBV in lymphoid cells |
Damage to individual host cells with little or no inflammatory response
Characteristic of certain viral infections |
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S. pneumoniae
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Gram + lancet-shaped diplococci
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N. meningitidis
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Gram - biscuit-shaped diplococci
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Blastomyces dermatitidis
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Broad-based budding yeast w/pseudoepitheliomatous hyperplasia
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Coccidiodes immitis
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Spherule w/endospores in pt from Southwestern US
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Malassezia furfur
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Spaghetti w/meatballs
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Cryptococcus neoformans
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Pleomorphic encapsulated budding yeast
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Histoplasma capsulatum
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Small intracellular yeast w/pseudocapsule
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Paracoccidioides brasiliensis
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Mariner's wheel in South American pt
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Sporothrix schenkii
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Cigar bodies and Spendore-Hoeppli phenomenon in rose-gardener
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CMV
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"Owl's eye" nuclear inclusion and cytoplasmic inclusions
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