Microbiologic sampling

As part of the material balance review, it is necessary to regularly and frequently undertake water sampling and analysis. From time to time, microbiological samples, scales, or other materials may also need to be analyzed. The questions of how to sample and what water sources to sample... 

This chapter deals with the determination of xenobiotic substances in biological materials. Although such substances can be measured in a variety of tissues, the greatest concern is their presence in human tissues and other samples of human origin. Therefore, the methods described in this chapter apply primarily to exposed human subjects. They are essentially identical to methods used on other animals, and in fact, most were developed through animal studies. Significantly different techniques may be required for plant or microbiological samples. 

Contamination is a threat to all microbiological sampling and is particularly difficult to control when investigating the microbiology of deep... 

Microbiological Sampling. Vegetative Cells. Cellular samples were obtained at various times after inoculation by sampling a known aliquot of the culture medium. These samples were centrifuged (Sorvall Superspeed RC 2-B, 7000 rpm) at 6°C for 10 min. The supemate was... 

As a rule, pyrolysis yields a complex mixture of products. This undoubtedly renders the interpretation of the results of the analysis of various substances by Py—GC more difficult. The difficulties involved, however, are not serious, and Py—GC is used extensively in analytical practice, e.g., in the analysis of polymers, in volatile organic compounds and microbiological samples. 

The composition of the material and the parameters investigated should remain unchanged over the entire period of use of the material. The study of the material stability in time will mainly depend on its role. If the material is going to be used in a short term interlaboratory study, the stability has to be monitored only over the real duration of the exercise and additionally mimic situations which may be encountered during its short lifetime, e.g. transport under severe climatic conditions. This may vary from some hours (e.g. microbiological samples) to several years for a CRM. The (in)stability should be studied or known before the RM is produced and should be monitored on the batch of RM. 

Fig. 1-10. Zobell sampler for collection of microbiological samples down to water depths of ca. 200 m.

Fig. 1-11. Niskin sampler for the collection of microbiological samples from deep ocean waters (General Oceanics).

These two clinical situations should be clearly distinguished before interpreting pulmonary secretion culture results, however they were obtained (Fig. 6). In the second simation, when the patient had received new antibiotics after the appearance of the signs suggesting the presence of pulmonary infection, no conclusion concerning the presence or absence of pneumonia can be drawn if culture results are negative. Pulmonary secretions therefore need to be obtained before new antibiotics are administered, as is the case for all types of microbiological samples. 

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