Keywords: Chapter 9a, Clinical Microbiology and Virology

Aseptic technique

Collection of specimens for microbiologic testing in a way that eliminates contamination with indigenous flora.
Branched chain DNA
Recombinant DNA method of detecting target nucleic acid using a signal amplification method that utilizes branched DNA probes.
Contamination
Presence of an organism that is not invloved with causing disease.
Denaturation
The process of double-stranded DNA molecules splitting apart into single stranded DNA molecules by heat or chemical reactions.
DNA transfer
Removal of the DNA from an agarose gel after electrophoretic separation. This process can occur by capillary draw or by direct flow.
Emerging infection
Any infectious disease which has come to medical attention within the last two decades. Many times, such diseases exist in nature as a zoonosis, and only emerge as human pathogens when humans come in contact with a formally isolated animal population, such as monkeys in a rain forest due to deforestation. Drug-resistant organisms could also be included as emerging infections, since they exist because of human influence. Some recent examples of emerging infections include human immunodeficiency virus, Ebola virus, and multi-drug resistant tuberculosis.

References

  1. Emerging Infections: A prevention strategy for the United States.
  2. Ebola fever.
Endemic
The constant presence of a disease or infectious agent within a given geographic area; may also refer to the usual prevalence of a given disease within such area. Hyper-endemic expresses a persistent intense transmission and holoendemic a high level of infection beginning early in life and affecting most of the population, e.g., Malaria in some places. (see zoonosis).
hemorrhagic fever
A hemorrhagic fever is a viral infection that causes high fever and profuse bleeding. The bleeding is largely due to disseminated intravascular coagulation (DIC). Several tropical fevers meet this general definition, including: Hantaan virus (Korean Hemorrhagic Fever), Lassa fever, Marburg fever, and, most recently, Ebola fever. Treatment for hemorrhagic fever is supportive only, although antisera is sometimes given, if available. All of these diseases are examples of Emerging Infections

References

  1. Garrett, Laurie. The Coming Plague. Random House, 1995. A scholarly account of emerging diseases, including HIV and drug-resistant tuberculosis. Well worth reading, but long.

  2. The Hot Zone. 1995, Random House. A rather sensationalist account of the search for the cause of Ebola fever. Perhaps that is why it is still on the New York Times best-seller list.The movie "Outbreak" is loosely based on this book.
    Hybrid capture
    Method of detecting target nucleic acid using an antibody to an RNA:DNA hybrid strand.
    Hybridization
    The process of a single-stranded nucleic acid molecule binding with a complementary single strand of nucleic acid to form a stable double-stranded molecule. Sometimes this is also termed renaturation.
    Ligase chain reaction
    An amplification method that uses shifts in temperature to denature DNA, allow hybridization (annealing) of four different primers, and ligation by enzymatic reaction. The four primers are labeled and thus allow for detection of product.
    Nucleic acid amplification
    The process of reproducing specific sequences of nucleic acid in the laboratory. Various methods exist which utilize enzymes that will generate copies of a target nucleic acid template under specific conditions.
    Polymerase chain reaction
    Prototype amplification assay which uses shifts in temperature to denature DNA, allow hybridization (annealing), and extension by enzymatic synthesis. Dr. K. Mullis recently received the Nobel prize for inventing this technique. See diagram.
    shell-vial
    A method for the culture of cytomegalovirus (CMV), wherein the inoculum is spun down by a centrifuge onto the surface of the cell culture. This improves the speed and sensitivity of CMV cultures.
    Signal amplification
    The process of increasing the signal attached to a nucleic acid probe after it hybidizes to the target sequences. Various methods exist which utilize either antibodies, other dna sequences and/or enzymatic reactions to accomplish
    Southern blot analysis
    Procedure of electrophoresing DNA fragments, transfer of DNA to membrane and hybridization with a nucleic acid probe. If the original material is RNA the process is termed Northern blot analysis.
    Viral transport medium
    Broth media for the transport of specimens for viral culture. This medium contains antibiotics that inhibit the overgrowth of bacteria and yeasts and contains buffers that stabilizes labile viruses.