This document summarizes key information about Streptococcus pneumoniae and Staphylococcus species. S. pneumoniae is a leading cause of pneumonia, particularly in young and old with damaged respiratory tracts. It is identified by being gram positive diplococci that are bile soluble and optochin susceptible. Staphylococcus aureus is one of the most common opportunistic pathogens causing infections like pneumonia, osteomyelitis, and abscesses. It produces exotoxins and enzymes that allow it to spread. Identification involves testing for coagulase, hemolytic activity on blood agar, and pigment production. Other Staphylococcus species like S. epidermidis are opportunistic pathogens

1. Streptococcus pneumoniae Staphylococci Faculty: Dr. Alvin Fox www.freelivedoctor.com

2. S. pneumoniae diplococci Pneumococcus autolysin bile solubility test optochin susceptibility capsule Quellung reaction Staphylococcus aureus opportunistic diseases food poisoning/enterotoxins toxic shock syndrome toxic shock toxin exfoliative toxin/scalded skin syndrome  ,  ,  ,  cytotoxins leucocidin lipase hyaluronidase protein A coagulase (+) or coagulase (–) Staphylococcus epidermidis KEYWORDS www.freelivedoctor.com

3. S. pneumoniae www.freelivedoctor.com

4. S. pneumoniae leading cause of pneumonia particularly young and old after damage to upper respiratory tract * e.g. following viral infection bacteremia meningitis middle ear infections (otitis media) www.freelivedoctor.com

5. S. pneumoniae  hemolytic pneumolysin degrades red blood cells under aerobic conditions grows well on sheep blood agar no group antigen www.freelivedoctor.com

6. Diagnosis - spinal fluid direct Gram staining detection of capsular antigen www.freelivedoctor.com

7. Autolysis - identification Bile peptidoglycan cell membrane lipoteichoic acid teichoic acid -choline autolysin www.freelivedoctor.com

8. C polysaccharide Teichoic acid Precipitates in serum C-reactive protein www.freelivedoctor.com

9. Not optochin sensitive optochin sensitive Identification www.freelivedoctor.com

10. Capsule prominent virulent strains anti-phagocytic carbohydrate antigens vary among strains www.freelivedoctor.com

11. Capsule immunity serotype specific vaccine contains multiple serotypes only for susceptible population www.freelivedoctor.com

12. Quellung reaction using antisera capsule "fixed" visible microscopically www.freelivedoctor.com

13. Pathogenesis Teichoic acid complement activation large numbers of inflammatory cells at infection site www.freelivedoctor.com

14. Therapy S. pneumoniae most strains susceptible to penicillin resistance is common www.freelivedoctor.com

15. STAPHYLOCOCCI Gram positive Facultative anaerobes Grape like-clusters Catalase positive Major components of normal flora skin nose www.freelivedoctor.com

16. Staphylococcus aureus www.freelivedoctor.com

17. One of commonest opportunistic infections - hospital and community : pneumonia osteomyelitis septic arthritis bacteremia endocarditis abscesses/boils other skin infections www.freelivedoctor.com

18. Food poisoning not an infection food contaminated by humans growth of bacteria production of enterotoxin onset and recovery both occur within few hours www.freelivedoctor.com

19. Food poisoning Vomiting nausea diarrhea abdominal pain www.freelivedoctor.com

20. Toxic shock syndrome fever rash desquamation vomiting diarrhea www.freelivedoctor.com

21. Toxic shock syndrome Toxic shock toxin Dissemination Organism no dissemination www.freelivedoctor.com

22. S. aureus babies scalded skin syndrome exfoliatin www.freelivedoctor.com

23. Lytic exotoxins:  toxin  (sphingomyelinase C)  toxin  toxins detergent-like leucocidins www.freelivedoctor.com

24. Protein A inhibits phagocytosis Protein A immunoglobulin Fc receptor BACTERIUM PHAGOCYTE www.freelivedoctor.com

25. Spread tissue-degrading enzymes lipase hyaluronidase www.freelivedoctor.com

26. Identification  hemolytic sheep blood agar yellow pigmented (aureus) mannitol fermentation coagulase-positive reference laboratories phage-typing www.freelivedoctor.com

27. Staphylococcus epidermidis major component, skin flora opportunistic infection - less common than S.aureus nosomial infections shunts, catheters artificial heart valves/joints www.freelivedoctor.com

28. Identification Non-hemolytic sheep blood agar Non-pigmented Does not ferment mannitol Coagulase negative www.freelivedoctor.com

29. Staphylococcus saprophyticus urinary tract infections coagulase-negative not usually differentiated from S. epidermidis www.freelivedoctor.com

30. Antibiotic therapy Resistance to penicillin penicillinase  lactam antibiotics (including methicillin [MRSA]) often ineffective modified penicillin binding proteins Vancomycin current drug of choice resistance has been observed www.freelivedoctor.com

31. GRAM POSITIVE COCCI S. aureus  hemolytic mannitol yellow + - Staphylococcus (Clusters) Streptococcus (pairs & chains) Catalase BETA: Bacitracin S. pyogenes (group A) CAMP/ Hippurate S. agalactiae (group B) Hemolysis Coagulase S. epidermidis nonhemolytic (usually) mannitol white ALPHA: Optochin /Bile Solubility S. pneumoniae GAMMA: Bile Esculin 6.5% NaCl Group D* Enterococcus Bile Esculin 6.5% NaCl Group D* Non- Enterococcus (*can also be alpha hemolytic) Note: S. viridans is Is alpha hemolytic and negative for all the tests below below + + + + + + + - - Summary Figure (Identification Scheme) www.freelivedoctor.com