Classification Of Bacteria Flashcards
Basis of classification of bacteria?
- Phenotype classification
- morphological
- anatomical
- staining
- cultural characteristics
- nutrition
- environment factor
- antigenic structure - Genotypic classification
- DNA-DNA hybridisation
- G+C content
Morphological classification?
- True bacteria
- Actinomycetes
- Spirochaetes
- Mycoplasma
- Rickettsiae and Chlamydiae
Type of true bacteria?
- cocci : these are spherical or oval cells. On the basis of arrangement of individual organisms they can be described as
- monococci ( cocci in single)
- diplococci ( cocci in pairs)
- staphylococci ( cocci in grape like cluster)
- streptococci ( cocci in chain)
- tetrad ( cocci in group of four)
- Sarcina ( cocci in group of 8)
- bacilli : these are rod-shaped bacteria.on the basis of arrangement of organisms, they can be described as
- diplobacilli
- streptobacilli
- palisades
- Chinese-letter form
- coccobacilli
- comma-shaped
Example of diplococci ?
Streptococcus pneumoniae
Example of staphylococci?
Staphylococcus aureus
Example of streptococci?
Streptococcus pyogenes
What are actinomycetes?
These are rigid organisms like true bacteria but they resemble fungi in that they exhibit branching and tend to form filaments.
They are termed such because of their resemblance to sun rays when seen in tissue sections
What is spirochaetes?
They are relatively longer, slender, non-branched microorganisms of spiral shape having several coils.
What are mycoplasma?
These bacteria lack in rigid cell wall and are highly pleomorphic and of indefinite shape. They occur in round or oval bodies and in interlacing filaments.
Rickettsiae and chlamydiae?
These are very small, obligate parasite, and at one time were considered closely related to the viruses. Now these are regarded as bacteria.
