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Streptococcus pneumoniae
Streptococcus pneumoniae, also known as pneumococcus, is a gram-positive bacterium that can cause pneumonia as well as other infections. It is encapsulated and appears as diplococci or short chains under microscopy. It grows on blood agar and chocolate agar, producing alpha hemolysis. Pneumococcus has over 80 serotypes defined by its capsular polysaccharide. The capsule helps it evade phagocytosis and causes virulence. Pneumococcus commonly causes lobar pneumonia through alveolar exudation and consolidation of portions of the lung. It can also spread through the bloodstream and cause complications like meningitis. Treatment involves penicillin and other antibiotics. Vaccines provide type-specific protection against
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Streptococcus pneumoniae
- 1. Streptococcus pneumoniae BY DRHASAN ASKARI BDS MS PHD FDS DDS MJDS MFDS MD –PRESIDENT OF INTERNATIONAL DENTAL RESEARCH UNIT LONDON
- 3. PNEUMOCOCCI • MORHOLOGY • Shapelancet shaped • Arrangement diplococci sometime short chains • Capsule encapsulated • Motility non motile • Spore non spore forming
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- 6. PNEUMOCOCCI • Staining • Gramstaining • Gram +ve staining • Violet coloured
- 8. PNEUMOCOCCI • Culture media •Blood agar and chocolate agar • Colonies • Small rounded colconies at first dome shaped later develop a central plateau with elevated rim • Alpha hemolysis on blood agar • Transformation • When uncapsulated pnemococci are cultured in the presence of DNA extracted from a capsulated pneumococcus encapsulated puneumococci of later type are formed this is called transformation.
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- 10. PNEUMOCOCCI • Lysis ofcolonies • Pneumococcal colonies are sensitive to lysis by an autolytic enzymes L alanine muramyl amidase that cleaves bond linking L alanine peptide to muramic acid of peptidoglycan wall.
- 11. PNEUMOCOCCI • Growth characteristics •Oxygen requirements: aerobic and facultative anaerobes. • Peptostreptococci are obligate anaerobes • Energy source is ferment sugar produces lactic acid but not gas. Lactic acid limits the growth. • Temperature 37degree c • 5-10% co2 promotes growth.
- 12. PNEUMOCOCCI • Antigen • Capsularpolysaccharide • A distinct for each of more than 80 serologic types. • B virulence is due to capsule which protect it from phagocytosis. • B cells response which provide type specific immunity. • M protein • Characteristics for each type. • C CHO • It is group specific common to all pnemococci.
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- 14. PNEUMOCOCCI • Enzymes • IgAprotease • It enhances organism ability to colonizes mucosa of upper respiratory tract. • Toxin • Pnemolysin • Binds to cholestrol in host cell membrane. • Inhibit antimicrobial properties of neutrophils and opsonic activity of serum.
- 15. PNEUMOCOCCI • Habitat andtransmission • Habitat • Normal inhabitant of u.respiratory tract. • Transmission • Via respiratory droplets
- 16. PNEUMOCOCCI • Pathogenes andclinical finding • pnemococcal lobar pneumonia: • It is characterized by exudation of fibrinous edema fluid into alveoli following by RBC and leukocytes many pnemococci are also present in alveoli. This causes consloidation of portion of lung. • Clinical finding • A sudden onset of high fever with violent , shaking chills • B sharp pleutal pain and friction rub. • C cough at first dry or productive of thin watery sputum : later bloody or rusty sputum.
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- 20. PNEUMOCOCCI • Bacteremia withits complication • From alveolar exudates organism reach bloodstream via lymphatics and causes bacteremia which have a traid of serious complication • Meningitis • Endocarditis • Septic arthritis • Sinusitis • Pericardiditis • Empyema • Otitis media
- 21. PNEUMOCOCCI • Meningitis • Pneumococcusis the second common bacterial pathogen that causes meningitis in adults. • Pathogenesis: • It may arises as a complication of pnemonia in which pneumococci reach the meninges by way of blood stream. • It results from a skull fracture ,permitting pnemococci from nasopharynx to enter the meninges. • Otitis media • Pnemococci is the etilogic agent of about 50% cases of otitis media in chidren.
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- 25. PNEUMOCOCCI • Diagnostic laboratorytest • Specimen blood pus sputum CSF • Microscopy gram +ve diplococci • Culture blood agar chocolate agar • Capsule swelling test quelling test • Omni antisera test • opotochin disk test • Animal inoculation test
- 26. PNEUMOCOCCI • Immunity • Typespecific immunity to reinfection with pnemococci develops. It is due to type specfic anticapsular antibodies.
- 27. PNEUMOCOCCI • Treatment • Penicillin •Erythromycin • Cephaothin • Chloramphenical • Prevention and control • Immunization with polyvalent ( ploysaccharide vaccine) • Vaccine provides protection for 5 years.
- 28. PNEUMOCOCCI • Difference b/wlobar pneumonia and bronchopneumonia • Lobar pneumonia • Cased 90% by pneumococci few cases by klebsiella pnemoniae, staph aureus. • Occurs in otherwise healthy individual b/w 30-50 years • Onset is sudden with high grade fever, shaking chills and bloody or rust sputum • Conslidation of whole lobe. • Complication bacteremia, meningitis,endocarditis, septic arthritis.
- 29. PNEUMOCOCCI • Bronchopneumonia • Causedby staphylococci streptococci, H influenzae proteus and pseudomonas. • Occurs infants ,old and those suffering chronic debiliating illness or immunosuppression. • Onset is insiduous with low grade fever and cough productive of purulent sputum. • Patchy pneumonic consolidation. • Complications: fibrosis, bronchiectasis,lung abscess.
- 30. Difference b/w lobarpneumonia and bronchopneumonia
- 31. Difference b/w lobarpneumonia and bronchopneumonia
- 32. Difference b/w lobarpneumonia and bronchopneumonia
- 33. Time out Difference b/wlobar pneumonia and bronchopneumonia