1 / 18

Streptococcus pneumoniae pneumococus

Streptococcus pneumoniae pneumococus. Pneumonia Meningitis bacteraemia. Description. Gram-positive diplococci (in pairs) Encapsulated ovoid or lanceolate coccus Non-motile Fastidious (enriched media) Blood or chocolate agar 5-10 % CO2 Alpha haemolysis + draughtsman appearance

lstroble
Download Presentation

Streptococcus pneumoniae pneumococus

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Streptococcus pneumoniaepneumococus Pneumonia Meningitis bacteraemia

  2. Description • Gram-positive diplococci (in pairs) • Encapsulated ovoid or lanceolate coccus • Non-motile • Fastidious (enriched media) • Blood or chocolate agar • 5-10 % CO2 • Alpha haemolysis + draughtsman appearance • Some strains are mucoid • Soluble in bile • Optochin sensitive

  3. Pathogenesis • Virulence factors • Capsular polysaccharide • The major factor • 84 serotypes • Both antigenic and type specific • Antiphagocytic • Serotype 3 , 7 are most virulent • 90% of cases of bacteraemic pneumococcal pneumonia and meningitis are caused by 23 serotypes • Quellung reaction , india ink • Pneumolysin • Membrane damaging toxin

  4. Carrier rate • Oropharyngeal flora of 5 – 70% of the population • Significance in respiratory infection

  5. Predisposing factors Aspiration of upper airway secretions ( endogenous ) No person-person spread Disturbed consciousness , general anaesthesia , convulsions , CVA , epilepsy , head trauma Prior LRT. VIRAL infection Preexisting respiratory diseases , smoking Chronic bronchitis , bronchogenic malignancy Chronic heart disease Chronic renal disease ( nephrotic syndrome ) Chronic liver disease ( cirrhosis) Diabetes mellitus Old age , (extreme of age ) Malnutrition , alcoholism

  6. Specific deficiencies in host defence • Hypogamaglobulinaemia • Asplenia , hypospenism ( tuftsin ) • Homozygous sickle cell disease • Coeliac disease • Multiple myeloma , leukaemia , lymphomas • Neutropenia • HIV Relative or absolute deficiency of opsonic antibody or inadequate manufacture of type specific antibody

  7. Diseases • Respiratory tract infections • Lobar pneumonia ( commonest cause of CAP ) • Empyema • Otitis media (6 months – 3 yrs ) • Mastoiditis • Sinusitis • Acute exacerbation of chronic bronchitis • Meningitis • Conjunctivitis • Peritonitis ( primary ) • Bacteraemia ( 15 % of pneumonia ) • septicaemia

  8. Clinical feature • Lobar pneumonia • Sudden onset • Fever • rigor • Cough , rusty sputum • Pleural pain • Signs of lobar consolidation • Polymorphonuclear leucocytosis • Empyema , pericarditis

  9. Meningitis • The most virulent pathogen of meningitis • Mortality ( 20% ) • Primary • Complicate infections at other site ( lung ) • Bacteraemia usually coexists • Bimodal incidence ( < 3 yr - > 45 yr )

  10. Mortality • Age (> 65 yr ) • Preexisting disease • Bacteraemia • Serotype 3 , 7

  11. Laboratory diagnosis • Specimen • Sputum • CSF • Swabs • Pus • Blood culture • Aspirate

  12. Microscopy • Gram stained smear • Gram-positive diplococci + pus cells • culture • Blood agar , chocolate agar + 10 % CO2 • identification • Alph-haemolytic colonies • Optochin sensitive • Bile soluble

  13. Sensitivity testing • Penicillin • susceptible • Sensitive • Nonsusceptible • Intermediate • Resistant • Ampicillin , amoxicillin • Erythromycin • Ceftriaxone , cefuroxime • Clindamycin • Fluroquinolones • tetracyclines • Vancomycin

  14. Treatment • Meningitis • Parenteral ceftriaxone + vancomycin • pneumonia • Outpatients • Erythromycin • Amoxacillin – clavulanic acid • Cefuroxime or ceftriaxone (IV) + oral b- lactam • Inpatients • Parenteral cefuroxime or ceftriaxone

  15. Prevention • 23 polysaccharide vaccine • Not effective in children < 2 yrs • >65 yrs • Functional or anatomical asplenia • SCD • 7-valent – protein- conjugated vaccine • Children < 3 yrs

More Related