Use of the diagnostic bacteriology laboratory: a practical review for the clinician.

EVective utilisation and understanding of the clinical bacteriology laboratory can greatly aid in the diagnosis of infectious diseases. Although described more than a century ago, the Gram stain remains the most frequently used rapid diagnostic test, and in conjunction with various biochemical tests is the cornerstone of the clinical laboratory. First described by Danish pathologist Christian Gram in 1884 2 and later slightly modified, the Gram stain easily divides bacteria into two groups, Gram positive and Gram negative, on the basis of their cell wall and cell membrane permeability to