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Environmental Analysis

Legionella pneumophila culture with serotyping [C242]

Published: May 10th, 2010

Revised: October 21st, 2015

Background

The Gram negative bacterium Legionella pneumophila is a common environmental cause of pneumonia, often associated with institutional outbreaks and environmental exposures. Legionella pneumophila is an endosymbiont of single celled protozoa that live in warm, stagnant water, particularly around temperatures of 30-40 °C. Building systems such as humidifiers and evaporative coolers may become contaminated by Legionella species including L. pneumophila if maintenance practices lapse or in the event of mechanical failures. Certain types of domestic hot water systems may also become affected. Most susceptible are systems in which untreated cold water is mixed with hot water downstream of the heating unit, usually as a means to prevent scalding at the faucet.

Analysis

This test uses selective and semi-selective culture-based assays recommended by the US-CDC to detect and differentiate culturable Legionella pneumophila Serotype 1 from Serotypes 2-15 in water and swab samples using a combination of physiological and immunological testing. Results of this test are reported quantiatively as CFUs of Legionella pneumophila Serotype 1 and L. pneumophila Serotype 2-15 (combined) per mL, or rated semi-quantitatively on swabs. For a more rapid species-specific test (24-48 hr), consider our molecular genetic Legionella pneumophila qPCR screen [M205]. Where L. pneumophila needs to be identified and enumerated specifically but serotyping is not required, consider Legionella pneumophila culture screen [C241].

Sample collection procedure

  1. Collect 500 mL of water in clean, new, screw-top bottle. For water sources expected to contain disinfectant chemicals such as chlorine, the collection container should include a suitable preservation buffer (the US-CDC recommends sodium thiosulfate to a final concentration of 0.1 M). We are pleased to provide sample collection containers to meet your needs. Please contact us prior to sampling to make arrangements.
  2. Collect culture swabs of internal surfaces of faucets, aerators, and shower heads using a sterile swab with buffered charcoal transport medium.
  3. Transport samples to the laboratory as soon as possible after collection. Samples may be transported at room temperature but must be protected from temperature extremes. Samples not processed with 24 hours of collection must be refrigerated.

References

  1. American Public Health Association. 2007. 9260 Detection of Pathogenic Bacteria: Section J – Legionella. APHA Standard Methods, Washington DC.
  2. Barbaree JM, Gorman GW, Martin, WT, Fields, BS, Morrill WE. 1987. Protocol for sampling environmental sites for legionellae. Appl Environ Microbiol 53: 1454-1458.
  3. Fields BS. 2006. Legionella, Chapter 79. In: Manual of Environmental Microbiology, 3rd edition. Hurst CJ, Crawford RL, Garland JL, Lipson DA, Mills AL, Stetzenbach LD (eds). Washington DC: American Society for Microbiology Press.
  4. US-CDC. 1992. Procedures for the recovery of Legionella from the environment. Atlanta GA : US Department of Health and Human Services, Public Health Service, 1-13.

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