1. Faculty: Dr. Alvin Fox

2. Key Words Pathogen/Epidemic Adhesion Normal flora Penetration Infection Invasiveness/spread Infectious diseases Extra/intra cellular pathogen Compromised host Exotoxin Opportunistic infection Endotoxin (non-specific immunity) Nosocomial Specific immunity Koch’s postulates Autoimmunity TransmissionBioterrorism

3. Pathogenicity virulence factors virulence factors number of initial organisms number of initial organisms immune status immune status

4. Pathogens EpidemicsEpidemics –healthy people

5. Koch's postulates isolatedisolated –diseased not healthy people growthgrowth –pure culture induce diseaseinduce disease –susceptible animals re-isolatedre-isolated –susceptible animals

6. Opportunistic infections compromised people –normal flora –environment

7. Opportunists - normal flora Skin – Staphylococcus aureus, – S. epidermidis – Propionibacterium acnes Intestine –Bacteroides *high numbers – Enterobacteriaceae *low number

8. Opportunists - environment air water soil food

9. Opportunists in hospital nosocomialnosocomial

10. Transmission airborne droplets airborne droplets food food water water sexual contact sexual contact

11. Host defenses GutGut –peristalsis – defecation respiratory tractrespiratory tract –ciliary action –coughing –sneezing urogenital tracturogenital tract –urination

12. Adhesion adhesin EPITHELIUM receptor BACTERIUM

13. S. pyogenes fibronectin F-protein lipoteichoic acid

14. E. coli with fimbriae

15. E. coli fimbriae mannose Type 1 galactose galactose – glycolipids – glycoproteins P

16. Penetration and spread Vibrio cholerae Salmonella enteritidis Salmonella typhi Epithelium

17. Connective tissue destrction Helps bacterial disseminationHelps bacterial dissemination –collagenase –hyaluronidase

18. Extracellular pathogens resistant to extra-cellular killing resistant to extra-cellular killing killed on phagocytosis killed on phagocytosis resist killing resist killing –by avoiding internalization

19. Protein A inhibits phagocytosis Protein A immunoglobulin Fc receptor BACTERIUM PHAGOCYTE

20. M protein inhibits phagocytosis M protein rr r peptidoglycan Complement fibrinogen

21. Intracellular parasite No fusion lysozome phagosome Fusion Enter cytoplasm

22. Killing of intracellular parasite Cell mediated immunityCell mediated immunity

23. Tissue Injury exotoxinsexotoxins endotoxins and non-specific immunityendotoxins and non-specific immunity - no antigen specific immunityspecific immunity - antigen

24. Exotoxins proteins proteins usually enzymes destroy cellular structures destroy cellular structures destroy extracellular matrix destroy extracellular matrix

25. A-B toxins Active Binding A Cell surface B

26. Diphtheria toxin and Pseudomonas exotoxin A – ADP-ribosylates elongation factor (EF2) – inhibits protein synthesis

27. Cholera toxin and E. coli labile toxin ADP-ribosylation of regulator adenylate cyclase activation cyclic AMP active ion and water secretion diarrhea

28. Shiga toxin - shigellosis Shiga-like toxin - enterohemorraghic E. coli lyses rRNA in ribosome lyses rRNA in ribosome death of epithelial cells death of epithelial cells poor water absorption poor water absorption diarrhea diarrhea

29. Botulinum toxin Botulinum toxin – inhibits acetylcholine release – inhibits nerve impulses – muscles inactive –flacid paralysis Tetanus toxin Tetanus toxin – inhibits glycine release – inactivates inhibitory neurons – muscles over-active rigid paralysis – rigid paralysis

30. Clostridium perfringensClostridium perfringens -collagenase Staphylococcus aureusStaphylococcus aureus - hyaluronidase Exotoxins - extracellular matrix of connective tissue

31. ProteasesProteases PhospholipasesPhospholipases Detergent-like actionDetergent-like action Membrane damaging exotoxins

32. destroys blood vessels destroys blood vessels stops influx inflammatory cells stops influx inflammatory cells creates anaerobic environment creates anaerobic environment allows growth of this strict anaerobe. allows growth of this strict anaerobe. C. perfringens phospholipase

33. Exotoxins Antibodies (anti-toxins)Antibodies (anti-toxins) neutralize –vaccination

34. Endotoxin LipopolysaccharideLipopolysaccharide peptidoglycan -endotoxin-like actionpeptidoglycan -endotoxin-like action cell envelope componentscell envelope components not proteins/enzymesnot proteins/enzymes

35. hypotension (tissue pooling of fluids) hypotension (tissue pooling of fluids) disseminated intravascular coagulation disseminated intravascular coagulation fever fever lack of effective oxygenation lack of effective oxygenation overall system failure overall system failure Septic shock

36. Endotoxins non-specific inflammationnon-specific inflammation cytokine releasecytokine release complement activationcomplement activation B cell mitogensB cell mitogens polyclonal B cell activatorspolyclonal B cell activators adjuvantsadjuvants

37. Specific immunity and immunopathology chronic infectionchronic infection tuberculosistuberculosis leprosyleprosy syphilissyphilis persisting bacterial remnantspersisting bacterial remnants autoimmunityautoimmunity

38. help survival on external surfaceshelp survival on external surfaces –H. influenzae –S. pneumoniae –N. gonorrhoeae –N. meningitidis IgA proteases

39. Bioterrorism airair –most common no previous exposureno previous exposure –zoonoses manifest initiallymanifest initially –colds/flu-like recognitionrecognition –clinically (e.g. common source clusters) –clinical microbiology –biodetection (environment) futurefuture