IDENTIFYING MICROORGANISMS

Classic microbiology relied on the information gained about an unknown microorganism from various biochemical tests to identify genus and species. Because a great number of these tests are normally required, identification is commonly a very slow and expensive process. However, experienced wine laboratory personnel can generally shortcut classic protocols for rapid, but tentative, identification. 

If identity confirmation is required, then the microorganism must be isolated from the wine (Section 13.9) prior to any characterization. It will probably be necessary to re-streak the isolate several times in order to obtain a pure isolate completely free from contamination. Unless a specific genus of microorganism is suspected, different media should be used initially in order to isolate the various microorganisms present in the sample. 

When examining microorganisms growing on agar, it is important to make note of colony characteristics as illustrated in Fig. 15.1. Such characteristics include shape (circular, irregular, or rhizoid), size (dimensions, normally expressed in millimeters), topography (flat, raised, convex, concave, or umbonate), presence of pigments, opacity (transparent. 

---

Due to the mainly qualitative nature of PCA, DFA, and HCA, the role of PyMS in microbiology has been somewhat restricted. For example, using these clustering methods, the use of PyMS to identify microorganisms can be a subjective process because it relies on the interpretation of complex scatter plots and dendrograms. Furthermore the qualitative nature of PCA, DFA, and FICA prevents the application of PyMS to quantitative microbial analysis, while limitations also arise from batch-to-batch variation of PyMS data.80... 

The antibioticogram analysis showed that in the long term AVL conditions, the microflora were resistant to the majority of antibiotics used and the application of these drugs were ineffective in about 50% cases, which led to the development of different broncho-pulmonary complications. The identified microorganisms showed mild resistance to amikacin, meropenem and polymyxin and total resistance to cephalosporins with exception of Staphylococcus spp. (Table 26.3). 

Borneman, J., Olatinwo, R., Yin, B., Becker J.O. An experimental approach for identifying microorganisms involved in specified functions utilisation for understanding a nematode suppressive soil. Australasian Plant Pathol 2004 33 151-155. 

Identifying Microorganisms Involved in Nitrogen Uptake 6. Nitrogen Uptake and Growth... 

The need to identify microorganisms rapidly has led to the development of a number of molecular identification and characterization tools. These have not yet become routinely adopted in the analytical or diagnostic laboratory but will probably do so in the future. One such technique isolates and amplifies 16S ribosomal DNA and, following sequencing of the bases, compares this with known sequences held in a reference library. This approach enables phylogenetic relationships to be derived even for those bacteria that have not previously been identified. Other systems examine the patterns of key constituents of the cells such as fatty acids and assign identities based on similarity matches to known reference cultures. 

Pasteur also succeeded in rescuing the French beer, wine, and silk industries from crises due to microbial contamination by identifying microorganisms and finding ways of protecting against them. He always emphasized close ties between chemical research and industry to his students, and as dean of Science Faculty at the University of Lille, he instituted night classes for workers and took students on tours of factories. 

Substrate test kits include those of the Enterotube, API, BioLog, and other related systems. They can be used to determine biochemical reactions of bacteria, yeasts, and molds within 1-3 days and thus aid in their identification. Some API system kits can be used to characterize organisms at the subspecies level by their capacity to utilize up to 100 substrates. The Biolog systems use carbon source metabolic fingerprints to identify microorganisms. 

METHODOLOGIES FOR IDENTIFYING MICROORGANISMS AND VIRUSES BY MASS CATALOGING OF RNAs... 

---