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Unformatted text preview: PATHOGEN: the scientific study of disease o Concerned with: 1st. ETIOLOGY: cause of disease 2nd. PATHOGENESIS: the manner in which a disease develops 3rd. structural and functional changes brought about by disease and their final effects on the body INFECTION: colonization of the body by pathogens o infection may exist in the absence of disease DISEASE: an abnormal state in which the body is not functioning normally o occurs when infection changes state of body NORMAL FLORA(microbiota): microorganisms that establish more or less permanent residence (colonizes) but that do not produce disease under normal conditions TRANSIENT FLORA (microbiota): may be present for several days or months and disappear OPPORTUNISTIC PATHOGEN: Under proper conditions mutualistic organisms may be come pathogens o EX: e.coli not harmful in large intestine, but harmful to other parts of body Like if in Urinary bladder cystitis; Or in CSF - meningitis M ICROBIAL ANTAGONISM: competition between microbes o normal microbiota can benefit the host by preventing the overgrowth of harmful microorganisms, protect the host by: o occupying niches that pathogens might occupy (competition for nutrients and space) o producing acids (harmful to invaders) o changing oxygen level of immediate environment o producing bacteriocins o Examples Vagina Normal flora maintain pH of 3.5 4.5; use of antiobitoics and excessive douching raises PH Inhibits growth of Candida albicans (because overgrowth causes vaginitus, yeast) Mouth Streptococci produce compounds that prevent growth of g+ and g- cocci Large intestine E. coli produce bacterocins, proteins inhibit growth of other bacteria Inhibits Shigella and Salmonella Large intestine Intestinal microbiota normally inhibit cl. Difficule and prevent it from attaching but antibiotics can eliminate normal microbiotic Gastrointestinal problems following antibiotics: Mild diarrhea, colitis, fatal toxemia ***PROBIOTICS: live microbes applied to or ingested into the body intended to exert a beneficial effect (ex: lactobacillis acidophilis) SYMBIOSIS: a relationship between normal microbiota and the host, where at least one organism depends on another o 3 types: COMMENSALISM: one organism benefits and the other is unaffected Examples: many normal microbiotia, like corynebacteria on eye; saprophytic bacteria in ear (both of these live on secretions and sloughed off cells and bring no apparent benefit or harm to host) MUTUALISM: benefits both organisms Examples: E. Coli in large intestine: Synthesize B and K vitamins (host benefits); Supply nutrients to normal flora (flora benefits) PARASITISM: One organism benefits and the other is harmed Examples: (tapeworm, bacteria, etc) KOCHS POSTULATES: **KOCH: German physician, Late 1800s, Worked with anthrax, Developed a framework for studying the etiology of infectious diseases o SUMMARY:...
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This note was uploaded on 07/12/2011 for the course NURSING 000 taught by Professor Clark during the Spring '11 term at Alabama.
- Spring '11