Identification of pathogens

Medical microbiology has to some extent, fallen beyond the rest of microbiology in its approach to the identification of disease-causing organisms. Due to the costs involved, routine identification of pathogens is still carried out through the classic bacteriological techniques.  This would normally entail the enrichment or isolation of bacteria from a clinical specimen using agar or broth procurement of a pure culture from the primary culture, identification of the bacterium through microscopy growth characterization and perhaps PCR. The reliance on the culture of pathogens means in that some general pathogens have been overlooked. Example for for many years the existence of Campylobacter as the most frequent causative agent of food poisoning was not known because of the hard in cultivating this genus in the laboratory. The cost of PCR continues to fall medical microbiology will embrace like concepts as viable but non culturable that are currently accepted in disciplines such as environmental microbiology, with a concurrent rise in the reliability of diagnosis.

Pathogen naming and identification are driven through patient symptoms rather than the whole properties of the microorganism. Example for, the enteric genera are all very closely associates on a genetic level but cause a variety of human diseases in Table 1. This is now becoming clearer from examination at the molecular level in which the pathogenic members of the Gram-positive genus Bacillus in Table 2 may even be the similar species but with different sets of plasmids.