ABSTRACT
This chapter reviews the methods commonly used to identify bacteria in clinical specimens and food and water samples. Although many methods employed in a diagnostic bacteriology laboratory can be used in a public health laboratory, certain screening tests using biochemical or immunologic techniques, phage typing procedures, and enumeration of viable bacteria are frequently employed in epidemiological research and public health laboratories. Bacteria have been classified by microscopic examination on the basis of size, shape, and staining properties. Bacteria may be classified as strictly aerobic or anaerobic, microaerophilic, and facultative according to their growth requirement for oxygen. The obligate aerobic organisms (for example, mycobacteria) grow well only in the presence of oxygen. A presumptive identification of bacteria can be made by the observation of the discrete masses of growth or colonies that can be grown on the surface of solid culture media from isolated bacteria.
