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Pneumococci
- 2. INTRODUCTION • The pneumococcus is the classic gram positive extra cellular bacterial pathogen. • It universally colonizes the nasopharynsx and is the major cause of pneumonia,sepsis and meningitis causing more morbidity and mortality than any other infection.
- 3. synonyms • Streptococcus pneumoniae- because of the genetic relatedness to streptococci. • Pneumococcus pneumoniae: because oftheir tendency to occur in pairs.
- 4. MORPHOLOGY • Gram positive • Diplococci • Flame shaped or lanceolate shaped • Size-1micro meter • Capsulated • Non motile and non spore forming.
- 5. Culture • Fastidious requires complex growth factors. • Grows only in enrichment medias. • Aerobe and facultative anaerobe • Opt tem-37 ◦c • PH-7.8 • Growth improved by 5-10% co2 GROWTH REQUIRMENTS:
- 6. Colony morphology • BAP- after overnight incubation, • Raised,circular,0.5-1mm in dm ,dome shaped glistening Colonies with alpha haemolysis. • Draughtman or carum coin appearance-prolonged incubation due to autolysis.
- 8. CULTURAL CHARACTERISTICS Liquid media • Glucose broth – uniform turbidity Autolysis enhanced by bile salts
- 9. Biochemical reactions • Catalase and oxidase negative • Bile solible • Fermant Inulin • Optochin sensitive. • Quellung reaction - positive
- 10. Bile solibility test Bacterial suspension + 2%Na deoxycholate Addition of 10% sodium deoxycholate Lysis of bacterial colony
- 11. Innulin fermentation MEDIA- Hiss ‘s serum sugar media Serum agar slope Pneumococci ferment inulin and produce acid
- 12. OPTOCHIN SENSITIVITY BAP with alpha haemolytic colonies Place 6µg disc containing optochin Zone of inhibition >14 mm-positive
- 13. QUELLUNG REACTION 1 drop of bacerial suspension +antisera +methylene blue
- 14. Animal pathogensity Intra peritoneal inoculation mice After 1-3 days Death Pneumococci demonstrated in Peritoneal exudate or heart blood
- 15. Virulence factors • Capsule anti phagocytic • Pneumolysin- membrane damaging toxin. Released by autolysin • Cytotoxic & complement activating proteins • Autolysins- responsible for release of virulence factors. • IgA protease
- 21. CLINICAL MANIFESTATIONS • Otitis media • Pneumonia(lobar/broncho) • Bronchitis • Meningitis • Pyogenic infections- conjunctivitis,suppuraive arthritis,peritonitis,Keratitis
- 23. LABORATORY DIAGNOSIS Gram-stained smear of sputum containing Gram-positive diplococci 1. Microscopic Examination DIRECT GRAM STAINING FLOURECENT STAININGCAPSULAR STAINING
- 24. 2.CULTURE ALPHA HAEMOLYSIS AUTOLYSIS BY BILE SALTS MUCOID COLONIS CARROM COIN APPEARANCE
- 26. IDENTIFICATION Colony morphology Biochemical reactions Serological tests Alpha haemolytic,mucoid dome shaped colonies Ferment innulin Quellung reaction Sensitive to optochin
- 27. 3.SEROLOGICAL DIAGNOSIS • Latex agglutination • ICT • Counter immuno electrophoresis For detection of pneumococcal antigen POSITIVE NEGATIVE LATEX AGGLUTINATION IMMUNOCHROMATOGRAPHY
- 28. 4.Molecular diagnosis • PCR • DNA Probes
- 29. 5.BIOMARKERS OF SEPSIS • CRP • PROCALCITONIN CRP Detection
- 30. 6.Animal pathogensity Intra peritoneal inoculation mice After 1-3 days Death Pneumococci demonstrated in Peritoneal exudate or heart blood
- 31. vaccines • PPV(Pnumococcal capsular polysaccharide vaccine) • Indications: • sickle cell disease • immunocompromised persons. • Chronic lung ,heart,liver disease. • PCV7 • 7 valent pnumococcal conjugate vaccine. • Effective in infants and toddlers. • Contains 7 pneumococcal capsular polysaccharide antigens conjugated to CRM197.
- 32. Treatment • DOC - Penicillin • 3rd generation cephalosporins • Vancomycin
- 33. HISTORY Peumococci was first isolated in 1881 by Sternberg in USA and Pasteur in France STERNBERG PASTEUR Causal relationship between pneumonia And pneumococci was identified by frankel and weichselbaum