Articles on Medical Diseases and Conditions

Histologic-type stains are used daily in the microbiology laboratory; most often Gram stain and acid-fast stain (Ziehl-Neelsen or its modifications). Both of these stains detect certain bacteria and to some extent help identify them. Other histologic stains perform the same purpose in tissue slide examination; the most common are paraaminosalycylic acid (PAS) and silver stains […]

In many cases, direct detection methods are not possible, are difficult and expensive, are unreliable, or are attempted with negative results. Serologic tests attempt to detect antibodies formed against antigens of an organism being searched for. The majority of organisms have a reasonably predictable antibody response. IgM-type antibodies appear first, most often in 7-14 days […]

Culture. This is the classic definitive method for detection and identification and will be discussed later in more detail. The major drawback is time; it usually takes 1 full day to grow the organism and then part or all of 1 day to identify it. It may take an additional day to isolate it before […]

Proper therapy for infectious disease requires knowledge of the etiologic agent. This knowledge can be gained in two ways: directly, either by isolating and identifying the organism in culture or by some method (e.g., fluorescent antibody or nucleic acid probe) that permits specific visual detection of the organism in clinical material; or indirectly, by using […]