MICROBIAL TAXONOMY Flashcards
An area of biological science comprising of
CLASSIFICATION, NOMENCLATURE and
IDENTIFICATION of organisms
Provides a consistent means to organize, name
and identify organisms
Provides a common label for every organism
Taxonomy
Organization of microorganisms that share similar morphologic, physiologic, and genetic traits into specific groups or taxa
Classification
(similar species)
Genus
(similar genera)
Family
(similar families)
Order
(similar orders)
Class
(similar classes)
Division
(similar divisions)
Kingdom
Most basic taxonomic group
Collection of bacterial strains
w/ common physiologic and
genetic features
Species
taxonomic
subgroup w/in a species
Subspecies
Biotype, serotype,
genotype
– groups below
the subspecies level that
share minor but specific
characteristics
Naming of microorganisms is based on established rules and guidelines set
forth by
International Code of Nomenclature of Bacteria (ICNB) or Bacteriological Code (BC)
Established in 1735 by
Carolus Linnaeus
genetic makeup
DNA base composition ratio
Nucleic acid base sequence base analysis
Genotypic characteristics
Process by w/c a microorganism’s key features are delineated
Identification
observable characteristics
- Macroscopic morphology
- Microscopic morphology
- Staining characteristics
- Environmental requirements
- Nutritional requirements
- Resistance profiles
- Antigenic properties
- Subcellular properties
Phenotypic characteristics
Genotypic Criteria
Examples
DNA base composition ratio
Nucleic acid base sequence analysis
4 bases (guanine, cytosine, adenine, thymine)
Example: an organism with a G/C content of 50% is related to
another organism w/ the same G/C content
DNA base composition ratio
Base sequence is the order of bases along a DNA or RNA strand;
the extent to w/c sequences are homologous b/n 2 microorganisms
can be determined by molecular methods.
Nucleic acid base sequence analysis
Characteristics of microbial growth pattern on culture media
E.g. size, shape, texture, pigmentation of colonies
Macroscopic morphology
Size, shape, intracellular inclusions, cellular appendages, and
arrangement of cells under the microscope
Microscopic morphology
Staining reaction/affinity to dyes as an aid to identification. E.g.
Gram stain, acid fast stain
Staining characteristics
Ability of organism to grow at various temperatures, in the
presence of oxygen and other gases, at various pH levels etc
Environmental requirements
Exhibition of a characteristic inherent resistance to specific
antibiotics, heavy metals, or toxins by certain microorganisms
Resistance profiles
Profiling microorganisms by various serologic and immunologic
methods
Antigenic properties
Establishment of molecular constituents like components of the: cell
wall, cell membrane and enzymatic contents
Subcellular properties
