Microbiological cultural methods development

Culture-dependent methods to characterize antibiotic resistance in the environment are essentially based on the guidelines developed for clinical and veterinary microbiology (e.g. [20, 66-69]). Nevertheless, several adaptations have been introduced. 

A rapid semiautomated microdilution method for the microbiological assay of the chloroquine has been developed by Desgardins (26). Antimalarial activity of chloroquine may be studied against cultured Plasmodium falciparum, microplates are used to prepare serial dilution of the drug. Parasites obtained from continuous stock cultures are subcultured in the micro-plates for 42 h. Inhibition of uptake of a radio labeled nucleic acid precursor by parasites serves as the indicator of antimicrobial activity. 

In microbiology two fundamental types of measurements are used by the analyst. The simplest ones consist in counting colonies on culture media in a Petri dish. Another principle consists in evaluating the most probable number of microbes by inoculating sub-samples into multiple tubes. The result of the latter is given by statistical tables. For both types of methods results are only available after a few days. For the presence of very few microbes, so-called presence/absence tests have been developed by microbiologists. They are mainly used for the detection of pathogenic microbes. For the last two types... 

The microbial strains studied were Salmonella thyphimurium (two exercises). Listeria monocytogenes (two exercises) and later Bacillus cereus. Staphylococcus aureus, and Clostridium perfrengens for food microbiology, and Escherichia coli. Enterococcus faecium, Enterobacter cloacae and Staphylococcus warneri for water microbiology. The results were discussed in meetings with all participants. Several standard operating procedures common for several methods were developed, tested and amended, e.g. measurement of pH of culture media, measurement of temperature in incubators, statistical treatment of results, etc. 

Mycoplasmas can be cultured in liquid or oti solid media. However, in contrast with other bacteria, their growth is slow, and a microbiological assay as described in the Ph. Eur. is time-consuming (at least 28 days). Alternative, rapid methods, based on nucleic acid technologies such as PCR, have been developed [36, 39]. Under certain conditions these methods may be used as an alternative method instead of the official, growth based method [40]. 

Since publication of the first edition of Wine Microbiology in 1997, the volume of new information and concepts has dramatically increased. Perhaps one of the most intriguing developments in the past decade has been application of real-time molecular methods. Based on similarities at the gene level, these methods have evolved beyond esoteric laboratory exercises to the point where real-world problems can be solved through rapid identification of microorganisms. Another relatively new application has been the use of starter cultures of nan-Saccharomyces yeasts, which yield wines that differ not only in flavor and aroma profiles but also in structure. 

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