Pneumococcus

Pneumoccoccus is a gram positive coccus . It exhibitis a marked tendency to arrangement as lanceolate diplococcus . It can grow poorly or ordinay media . It usually ferments insulin . It is soluble in bile and is frequent pathgens to man . Pneumococcus may be termed as Diplococcus pneumoniae or streptococcus pneumoniae because it closely resembles to Streptococcus viridans .

Morphology

i)                    Shape and size – oval or lanceolate diplococcus in pairs . It is 1 μ in length .

ii)                   Usually it is arranged in pair . Short chain of three to four may be present on artificial media particularly  in fluid variety .

iii)                 Each pair is enclosed in a single capsule .

iv)                 Non sporing .

v)                  Non motile .

vi)                 Gram positive and non-acid fast diplococcus .

Pathology produced by Pneumococcus –

1.      The organism usually present in throat enters along nasopharynx  → to nose ( Rhinitis ) → transverse along nasoclear duct  → to lacrimal sac ( dacrocystis ) . It may often be found in cornea ( corneal ulcer ) .

2.      From throat , the organism will enter into Eustachian tube  → to middle ear ( otitis media ) .

3.      From throat ,, the organism wil enter into lower respiratory tract producing  → Laryngitis  → Bronchitis and Broncho pneumonia  → Lobar pneumonia   → Seticaemia and from blood , the organism localises in different serous sacs like pleura ( pleurisy ) , pericardium ( pericarditis ) , peritoneum ( peritonitis ) , meninges (meningitis ) synovial membrane ( arthritis ) may invade serious sacs directly .

4.      From throat , the organism may enter into mastoid bone ( Mastoditis ) and it will lead to osteomyelitis of mastoid bone and inflammation of Mastoid air sinus  → leads to subdural abscess  → when abscess bursts , the organism will enter into the meninges ( pneumococcal meningitis ) .