The document summarizes information about Streptococcus pneumoniae (pneumococcus): 1. It is a gram-positive coccus that appears in pairs (diplococci) or chains under microscopy. It is identified by being alpha-hemolytic, optochin-sensitive, and exhibiting a Quellung reaction showing its polysaccharide capsule. 2. Pneumococcus is a common cause of pneumonia as well as other invasive diseases. Virulence factors like its polysaccharide capsule allow it to evade the immune system and cause disease. 3. Treatment involves penicillins or other antibiotics. Vaccines targeting the 90+ capsular serotypes help prevent pneumococcal disease.

1. DR KAMRAN AFZAL ASST PROF MICROBIOLOGY Streptococcus pneumoniae

2. Gram positive cocci Catalase Negative Streptococci (Chains) Catalase Positive Staphylococci (Clusters) Haemolysis on Blood agar Alpha or incomplete Strept pneumoniae Or viridans Beta or complete Gropu A, B, C, D Coagulase

3. The Genus Streptococcus FAMILY Streptococcaceae Some important pathogens, commensals of mucous membranes Opportunistic pathogens 40 species, in 6 clusters Strong fermenters of carbohydrates -> Lactic acid Facultative anaerobes Peptostreptococci are obligate anaerobe S

4. Clinically Important Streptococci Group Species Lancefield Group Type of Haemolysis Pyogenic S. pyogenes S. agalactiae S. eqisimilus A B C β β β Mitis S. pneumoniae S. mitis S. sanguis O O H α α α Anginosus S. anginosus G, F α Salivarius S. salivarius K γ Bovis S. bovis D α Mutans S. mutans No γ

5. Haemolytic Activity β Haemolysis Complete lysis/clearing of RBCs induced by bacterial haemolysins α Haemolysis Incomplete haemolysis of RBCs H 2 O 2 oxidizes Hb -> Methaemoglobin (greenish) γ Haemolysis No haemolysis

6. Strep pneumoniae Morphology Gram positive lancet shaped diplococci arranged in pairs In body fluids in addition we may see it singly or in short chains

7. Antigenic Structure The organism is capsulated with 90 different capsular polysaccharide types Elicits humoral response - formation of antibodies The cell wall contains another polysaccharide that is common to all pneumococci C- Substance that binds to C-reactive protein

8. Virulence Factors Polysaccharide capsule - the major virulence factor It prevents phagocytosis by host immune cells Autolysin Activation of this protein lyses the bacteria -> Pneumolysin Pneumolysin Lyses host cells of immune system Facilitates colonization M-protein Antiphagocytic Lipoteichoic acid Activates complement IgA protease Helps in colonization

9. Predisposing Factors Alcohol or drug intoxication Immunocompromised Elderly Abnormality of the respiratory tract Viral infections, bronchial obstruction and respiratory tract injury Abnormal circulatory dynamics Splenectomy Chronic diseases Sickle cell anaemia

10. Transmission And Colonisation

11. Pathogenesis

12. Diseases Caused Non-invasive disease Sinusitis (sinuses) Otitis media (middle ear) Pneumonia (lungs) Invasive disease Bacteraemia (blood) Meningitis (CNS) Endocarditis (heart) Peritonitis (body cavity) Septic arthritis (bones and joints) Others (appendicitis, salpingitis, soft-tissue infections) PNEUMOCOCCAL INFECTION Pneumonia

13. Pneumococcal Disease Wenger et al., J Infect Dis, 1990 Pathogenic agents in bacterial meningitis in persons aged  60 years in the USA Others 26% Streptococcus pneumoniae 49% Group B streptococcus 3% Haemophilus influenzae 4% Neisseria meningitidis 4% Listeria monocytogenes 14%

14. Clinical Features Septicemia Pneumonia Fever Hypotension Acute confusion Chills Dyspnea Tachypnea Headache Tachycardia Fever Dyspnea Lung consolidation Hemoptysis chills Chest pain Cyanosis malaise Rust colored sputum

15. Pneumonia Complications Bacteraemia in 15  20% of patients high mortality despite appropriate antibiotic therapy overall case fatality rate 15-20% higher case fatality rates (30-40%) for elderly Spread of pneumococci in the blood to other normally sterile sites can cause other invasive pneumococcal diseases (e.g. meningitis) Empyema (pus in the pleural cavity) in about 2% of cases

16. Lab Diagnosis Specimens Sputum Blood CSF Swabs Urine Inoculation Blood, chocolate agar at 37 o C for 24-48 hrs

17. Cultural Characteristics No growth on simple media Grow well on enriched media like blood agar Grow better in 5-10% CO 2 The colonies are alpha haemolytic, 1-2 mm Have the tendency to undergo autolysis They collapse in the centre and raised at the periphery giving ‘Draughtsman’s’ colonies appearance

18. In addition to alpha haemolysis, this strain of Streptococcus pneumoniae is producing abundant polysaccharide capsular material evidenced by the mucoid or "oil droplet" appearance on the colonies

19. Identification Gram staining Catalase negative Alpha haemolysis Soluble in bile salts Sensitivity to optochin Capsular swelling (Quellung reaction) Antigen detection Animal pathogenicity Molecular typing

20. Gram Staining (Direct microscopy) Lancet (lanceolate) shaped diplococci having long axis in line with each other Pus cells are also present

21. Alpha haemolysis

22. Optochin sensitivity 16 mm

23. Capsular Swelling Reaction If sputum or specimen mixed with a polyvalent antiserum and then stained, the capsule increases in size The Quellung test is used in pneumococcus typing

24. Bile solubility The organisms are rapidly lysed by surface active chemicals like bile salts

25. Antigen Detection Capsular polysaccharide antigen In serum, CSF or Urine By latex agglutination method Rapid method Useful to diagnose bacteraemia and meningitis

26. Animal pathogenicity Intraperitoneal injection of the organisms The animal dies and the microorganisms can be isolated from blood

27. Molecular typing PCR RFLP DNA sequencing

28. Sensitivity testing

29. Treatment Penicillins, tetracylines and macrolides They have remained sensitive over the years Resistant strains are being reported Ceftriaxone for the resistant strains Vancomycin for ceftriaxone resistant strains

30. Pneumococcal Vaccine 90 different capsular types 23-valent pneumococcal vaccine contains purified capsular polysaccharides Serotype coverage 2,3 85-90% of serotypes responsible for all cases of invasive pneumococcal disease Vaccine includes major serotypes that have developed antimicrobial resistance

31. Case History A 53 year-old man with non-insulin-dependent diabetes Presents with symptoms of fever, chills and cough with rust colored sputum for 05 days Pulse of 110/min, Fever 103 0 F Crackles in right lung field along with decreased air entry on respiratory examination

32. X-ray chest

33. Sputum Gram’s Stain

34. Culture

35. Susceptible to Optochin

36. Sensitivity testing

37. Causative agent is Streptococcus Pneumoniae It is the only strep that is susceptible to Optochin

38. Special technique..