- Pneumococcus is a partner of the upper respiratory tract.
- Pneumococci essential pathogen of pneumonia and oddities media in children.
- Pneumococci is reclassified into the streptococcus pneumoniae.
- It is a small, slightly elongated, gram positive cocci that is arranged in pair.
- Each coccus consist two ends, one end is rounded or broad and other is pointed.
- Each pair is enclosed by the capsule.
- Pneumococcus is non motile and non sporing.
- Pneumococci are aerobs and facultative anaerobes.
- Pneumococci growth require 37° C temperature and 7.8 PH.
- On the blood agar, the colonies are small, dome shaped after 18 hour incubation.
- On the prolonged incubation, colonies flat with raised edge.
- Pneumococci produce the uniform turbidity in the liquid medium.
Pneumococcus Biochemical reactions
- Pneumococci ferment several sugars with the production of acid.
- Generally, pneumococci are soluble in the bile.
- Pneumococci is the catalase and oxidase negative.
- Bile solubility test is a essential test to differentiate the pneumococcus from the streptococci.
Pneumococcal resistance mechanism
- Pneumococci are more sensitive to the usual antiseptics.
- Pneumococci are destroyed at 52° C temperature for 15 minutes.
Pneumococcal Antigenic structure
- The most important antigen of pneumococcus – is capsular polysaccharides.
- Other antigens are – M protein and cell wall carbohydrate.
- Capsular polysaccharide – It is a specific pneumococci that is classified based upon the capsular polysaccharide nature.
- M protein – It is another type of pneumococci that is associated with antibody and virulence to M protein.
- Cell wall carbohydrate – It is a specific carbohydrate Antigen that called C – substance.
- It is precipitate due to abnormal protein and occur in the acute phase of pneumonia and disappear during convalescence.
- C – Substance also occur in the patient blood with some other disease, is called C – reactive protein (CRD).
- Streptococcus pneumoniae is the most common bacteria which is causing pneumonia (both lobar and bronchopneumonia).
- It is second most important cause of pyogenic meningitis.
- This type disease most commonly occur in the children.
Pneumococcus Laboratory diagnosis
- CSF, sputum, blood, pleural exudate, etc.
- For pneumococci septicaemia, blood culture is useful.
Collection and transport
- All sample should be collected in the sterile container under the aseptic techniques and transport immediately in the lab.
- Direct microscopic – Gram staining of smear demonstrate the large number of polymorphs and typical organism.
- Culture – The sample should be incubated on the blood agar.
- The sample also inoculated at 37° C temperature for 24 hours in the presence of CO2.
- Biochemical reaction – Biochemical test describe the steps to cocas pneumoniae is differentiate from the streptococcus viridans.
- The biochemical test is insulin fermentation and bile solubility test.
Animal pathogenicity test
- The heart blood and peritoneal exudate of pneumococci.
- Antibiotic of choice – Parenteral penicillin.
- Reference – Textbook of microbiology 5th edition, By DR. C. P. Baveja.
- Page no. 196 – 198.