Streptococcus pneumoniae Versus Viridans streptococci: Introduction and Differentiating Features

Streptococcus pneumoniae versus Viridans streptococci

  Introduction of Streptococcus pneumoniae versus Viridans streptococci

Streptococcus pneumoniae versus Viridans streptococci can be easily understood. S. pneumiinae is the commensals of the upper respiratory tract. It is an important pathogen of pneumonia and otitis media in children. It differs from streptococci in its morphology  (diplococci), bile solubility, optochin sensitivity, and a specific polysaccharide capsule.  Its other name is the pneumococcus. It is Gram-positive, small ( 1 µm in diameter), slightly elongated cocci arranged in pairs i.e. diplococci with the broad ends in apposition as shown above image.

Viridans streptococci produce alpha hemolysis on blood agar. Viridans means green. They are commensals of the mouth and upper respiratory tract. This group contains many species, e.g. Streptococcus salivarius, Streptococcus mutans, Streptococcus sanguis, and Streptococcus milleri. They cause endocarditis and dental caries.

Differentiation features of Streptococcus pneumoniae and Viridans streptococci  on the basis of the following properties are  as follows:

  1. Colony characteristics
  2. Bile solubility  test
  3. Optochin (ethyl hydrocupreine hydrochloride) 5µg sensitivity test
  4. Inulin fermentation
  5. Mice intraperitoneally when injected
  6. Mice intracerebrally when injected
  7.  Presence of Capsule
  8. Quellung reaction
Streptococcus pneumoniae versus Viridans streptococci
Streptococcus pneumoniae versus Viridans streptococci

On these properties, Streptococcus pneumoniae versus Viridans streptococci can clearly understand as shown above picture.

Further Readings

  • Bailey & Scott’s Diagnostic Microbiology. Editors: Bettey A. Forbes, Daniel F. Sahm & Alice S. Weissfeld, 12th ed 2007, Publisher Elsevier.
  • Clinical Microbiology Procedure Handbook Vol. I & II, Chief in editor H.D. Isenberg, Albert Einstein College of Medicine, New York, Publisher ASM (American Society for Microbiology), Washington DC.
  • Colour Atlas and Textbook of Diagnostic Microbiology. Editors: Koneman E.W., Allen D.D., Dowell V.R. Jr, and Sommers H.M.
  • Cowan & Steel’s Manual for identification of Medical Bacteria. Editors: G.I. Barron & R.K. Felthani, 3rd ed 1993, Publisher Cambridge University Press.
  • Jawetz, Melnick and Adelberg’s Medical Microbiology. Editors: Geo. F. Brook, Janet S. Butel & Stephen A. Morse, 21st ed 1998, Publisher Appleton & Lance, Co Stamford Connecticut.
  • Mackie and Mc Cartney Practical Medical Microbiology. Editors: J.G. Colle, A.G. Fraser, B.P. Marmion, A. Simmous, 4th ed, Publisher Churchill Living Stone, New York, Melborne, Sans Franscisco 1996.
  •  Manual of Clinical Microbiology. Editors: P.R. Murray, E. J. Baron, M. A. Pfaller, F. C. Tenover and R. H. Yolken, 7th ed 2005, Publisher ASM, USA
  •  Textbook of Diagnostic Microbiology. Editors: Connie R. Mahon, Donald G. Lehman & George Manuselis, 3rd edition2007, Publisher Elsevier.
  • Topley & Wilsons Principle of Bacteriology, Virology, and immunology Vol I, II, III, IV & V. Editors: M.T. Parker & L.H. Collier, 8th ed 1990, Publisher Edward Arnold publication, London.
  • Medical Microbiology-The Practice of Medical Microbiology Vol-2-12th Edn. –Robert Cruickshank
  • District Laboratory Practice in  Tropical Countries  –  Part-2-   Monica Cheesebrough-   2nd Edn Update
[8290 visitors]

Comments

© 2025 Universe84a.com | All Rights Reserved

12731454

Visitors