Full text loading...
Abstract
SUMMARY: Biochemical procedures for the differentiation of fungi in general and pathogenic fungi in particular have been slow to develop because many such organisms possess a sufficiently varied morphology to allow of considerable subdivision by that means alone. When, however, one considers organisms with a very reduced morphology, such as yeasts, the picture is very different and biochemical procedures have long been standard. Dependence on morphology for the identification of filamentous fungi has several disadvantages, of which slowness and lack of precision are the two most important. It is not desirable in medicine to have to wait several months till a particular identifiable structure is produced and there are a few pathogenic fungi which remain permanently nondescript. The lack of precision is best shown by the plethora of synonyms and ill described ‘species’ that have long plagued mycology.
The capacity of fungi to utilize various compounds and the chemical nature of their structure have both been used as methods of differentiation. The former method has been successfully used to show differences between morphologically similar organisms in several genera such as Microsporum, Trichophyton and Madurella. This method has also proved of the utmost value in distinguishing those aerobic Actinomycetes which are responsible for mycetoma from one another. Tests commonly used are the ability to degrade compounds such as casein, tyrosine, xanthine and urea or the lack of ability to grow in the absence of certain amino acids or vitamins or the ability to assimilate a particular compound such as dulcitol, erythritol, lactose or sucrose. Chemical analysis of fungi has not yet progressed so far but differences have been demonstrated, and the detection of arabinose and di-aminopimelic acid in the cell walls of Actinomycetes appears to be on the verge of becoming standard technique.
- Accepted:
- Published Online: