Classification and identification of organisms are two separated but inter-related processes. Classification involves the identification of groups of organism that share common properties and that differ from other groups. The classification and identification of organisms are two separate but inter-related processes. Classification involves the identification of groups of organism that share common properties and that differ from other groups. Identification entails the assignation of an unknown organism to a group within a scheme of classification.
Classification Classification is the process of recognizing and describing groups of living organism. Classification is important. It is an activity essential to all scientific work. It would be impossible to make any generalizations about microorganisms and their role in nature if we could only refer to each strain by a different and arbitrary name. We must arrange microorganisms into groupsthat share common properties, so that we can talk about sets of strains that have properties in common.
Identification Identification is a branch of systematics. It is, however, different from classification, which tests of the way living organisms are grouped together into taxonomic groups or taxa (singular taxon). Identification deals with the process of allocating a new specimen (an ‘unknown’) to the correct and previously described taxon.
Importance : Identification is a very important practical activity, which will concern most microbiologists from time to time. Large areas of microbiological work are heavily dependent on good identification. Some areas, such as hospital microbiology, are almost entirely concerned with identification and are collectively referred to as diagnostic microbiology. It may be emphasized that numerous kinds of microbiological work. By sequencing a number of rRNA genes and comparing them with genes in the databases, a picture of the composition of the microbial population began to emerge.
Because this type of analysis was not dependent on the ability to grow the microorganisms on laboratory media, it was possible to identify tentatively not only the microbes that were present but also the microbes that were not bein gcultivated. Sometimes the sequences of rRNA genes were close to those of cultivated organisms, but just as often the sequences were very distant from known organisms, suggesting that whole phylogenetic groups of microbes had been missed completely in previous cultivation attempts.
In many environmental seetings, less than 1% of the organisms for which rRNA gene sequences were obtained were recognizable as cultivated strains or had identical sequences to microbes isolated from that environment by classic cultivation methods. This was true for bactria and archaea and even more true for the eukaryotic microbes. Except for eukaryotic human pathogens and a few model organisms, such as Dictyostlium and Tetrahymena…
The API system (BioMerieux) is widely used and while it is not as sophisticated as the vitek, particularly with sample inoculation, it has been semi-qutomceted as the ATB system with an accompanying change from 20 to 32 biochemical test, options per strip. Lapage (1973) designed a computer program which showed that the average of 29-32 tests were required for reliable identification of aberrant strains of Euterobacteriaceae and non-fermenting Gram negative rods end that additional test did not improve the accurency.
Two system consists of a densitometer, inoculator reader and data-handler and allows a choice of rapid or overnight incubation, depending on the test type. It has both identification and antimicrobial susceptibility testing options. A particularly useful output feature is the typically index which provides that user with culture identification and indicates whether the isolate is typical or compared with the base profile for that species.
API systems API systems are available for: Enterobacteria (20E, Rapid, 20E, 10S); Non-enteric Gram-negative rods (20NE); Staphylococci (20/STAPH); Streptococci (20/STREP); Anearobes (20A); Heterotrophic aerobes (20B); Yeasts (20C/AUX); Fermentation, oxidation, assimilation (50CH); Enzyme tests (ZYM). Suspensions of the organisms are added to cupules in plastic galleries. There are incubated overnight. Some tests then require reagents to be added. Results are read from codes and a Profile Register. There is a computer identification service.