Q Should a clinical microbiology lab in a community hospital be doing environmental cultures on specimens collected in the hospital? I am referring specifically to culturing of deionized water, swabs of cleaned whirlpools in physical therapy, water samples from cleaned endoscopes, water from dialysis tubing, and sterilized spore strips from the operating room and central processing. If it is appropriate, are there any references to use as guidelines for procedures and interpretation of results?
A The routine microbiologic sampling of the hospital environment is not useful or cost effective unless it is performed for a specific epidemiologic purpose (e.g., investigate a cluster of nosocomial nosocomial /noso·co·mi·al/ (nos?o-ko´me-il) pertaining to or originating in a hospital.
1. Of or relating to a hospital.
2. respiratory infections), to monitor sterilization processes, or to detect contamination of water used in the dialysis unit and the laboratory. Therefore, the need to perform environmental cultures should be determined by the members of the infection-control committee and to include, as a minimum, a representative from the microbiology laboratory, the hospital epidemiologist, and the infection control practitioner. The specimens should be sent to an appropriate reference laboratory in the event that the hospital laboratory cannot perform the cultures.
After approval by the infection control committee, the microbiology laboratory must apply the appropriate procedure and interpretive guideline for the myriad of potential specimens that may be submitted for culture. The problem confronting the microbiology laboratory is that the procedures for culturing potential environmental specimens are scattered among numerous publications, associations, societies, governmental agencies, and organizations. For example, NCCLS NCCLS National Committee for Clinical Laboratory Standards (www.nccls.org) publishes a procedure for the evaluation of laboratory water. (1) The Association for the Advancement of Medical Instrumentation (www.aami.org) publishes standards for the water used to prepare dialysate dialysate /di·al·y·sate/ (di-al´i-sat) the fluid and solutes in a dialysis process that flow through the dialyzer, do not pass through the membrane, and are discarded along with removed toxic substances after leaving the dialyzer. used in dialysis units. These standards include the procedures and interpretive guidelines for endotoxin Endotoxin
A biologically active substance produced by bacteria and consisting of lipopolysaccharide, a complex macromolecule containing a polysaccharide covalently linked to a unique lipid structure, termed lipid A. contamination and total viable microbial counts in the water. Often, the dialysis unit has a copy of these standards. The American Society for Microbiology The American Society for Microbiology (ASM) is a scientific organization, based in the United States although with over 43,000 members throughout the world. It is the largest single life science professional organization and its members include those whose interests encompass basic (www.asmusa.org) publishes a handbook containing procedures for evaluating sterilization processes and culture of water and other environmental specimens. (2) Additional information can be obtained from the Centers for Disease Control and Prevention Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center. (www.cdc.gov/ncidod/hip) on healthcare guidelines; the American Public Health Association The American Public Health Association (APHA) is Washington, D.C.-based professional organization for public health professionals in the United States. Founded in 1872 by Dr. Stephen Smith, APHA has more than 30,000 members worldwide. (www.apha.org) on standards for the examination of water and wastewater; and other selected publications. (3,4) Also, the members of the infection control committee are a valuable resource for identifying a source for a specific procedure.
1. NCCLS. Preparation and testing of reagent water in the clinical laboratory. 1997.
2. Gilchrist MRJ MRJ Mitsubishi Regional Jet
MRJ Macintosh OS Runtime for Java
MRJ Maximally Random-Jammed
MRJ Macintosh Runtime for Java , ed. Epidemiologic and infection control microbiology. In: Clinical Microbiology Procedures Handbook, Isenberg HD, ed. American Society for Microbiology. 1992;pp:11.0.1-11.17.4.
3. Mietzner SM, Stout JE. Laboratory Detection of Legionella Legionella /Le·gion·el·la/ (le?jah-nel´ah) a genus of gram-negative, aerobic, rod-shaped bacteria (family Legionellaceae), normal inhabitants of lakes, streams, and moist soil; they have often been isolated from cooling-tower water, in Environmental Samples. Clin Microbiol Newsl. 2002;24:81-85.
4. Wenzel R. Prevention and Control of Nosocomial Infections. Lippincott, Williams and Wilkens. 1993. New edition 2003.
--David Sewell, PhD, ABMM ABMM American Board of Medical Microbiology
ABMM American Board of Medical Management
ABMM Anti-Ballistic Missile Missile
ABMM American Board of Medical Malpractice
Director of Microbiology Veterans Affairs Medical Center