Opportunistic infections vImmcompromised people v Normal flora skin Or microbes from Staphylococcus Environment aureus Air S. epidermidis Propionibacterium Water aches soil Intestine -Bacteroides food high numbers Enterobacteriaceae low number
Opportunistic infections Or microbes from Environment Air Water soil food Immcompromised people Normal flora •Skin – Staphylococcus aureus, – S. epidermidis – Propionibacterium acnes •Intestine –Bacteroides *high numbers – Enterobacteriaceae *low number ……
The colon is Antibiotics kill Clostridium difficile colonized by gains a foothold Neutrophils and red large numbers many of these and produces blood cells leak intol of commensal commensal bacteria toxins that cause gut between injured bacteria mucosal injury epithelial cells Gut lumen C difficile 00d Figure 10-25 Immunobiology, 6/e ( Garland Science 2005)
Figure 10-25
Outline of the lecture v Normal flora =normal microbiota Y Opportunistic infections v Koch's postulates v Virulence of bacteria Invasive oxins -endotoxin exotoxin v Bacterial biofilms v Modes of infectious disease transmission Infections v Control of nosocomial infection
Outline of the lecture Normal flora =Normal microbiota Opportunistic infections Koch's postulates Virulence of bacteria Invasive Toxins – endotoxin exotoxin Bacterial biofilms Modes of infectious disease transmission Infections Control of Nosocomial Infection
Innocent or Murder? Disease Etiology: Koch's Postulates Who is to be blamed? Copyright O The McGraw-Hill Companies, Inc. Permission required for reproduction or displ ① Specimen from patient Pure cult Observe animal for disease charactenstics nodulation of est subject
Disease Etiology: Koch’s Postulates Innocent or Murder? Who is to be blamed?
Koch's postulates The postulates formulated by robert Koch and Friedrich Loeffler in 1884 and refined and published by Koch in 1890 · Isolated diseased not healthy people Modification of Koch's Growth postulates pure culture in vItro -Can not be culture in vitro? induce typical disease No susceptible animals? susceptible animals How identifying a virus re-isolated causing disease susceptible infected animals EXample Identification of sars cov Table 9-1, p. 150
Koch's postulates The postulates formulated by Robert Koch and Friedrich Loeffler in 1884 and refined and published by Koch in 1890 • Isolated – diseased not healthy people • Growth – pure culture in vitro • induce typical disease – susceptible animals • re-isolated – susceptible infected animals Example: Identification of SARS CoV Modification of Koch’s postulates -Can not be culture in vitro? -No susceptible animals？ -How identifying a virus causing disease ? Table 9-1, p. 150