Legionella Culture

Legionella colonies on culture plate.


Legionnaires’ disease is an acute lobar pneumonia with multi-system manifestations.

Legionnaires’ disease results from exposures to water sources containing the organism. Predisposing factors in a susceptible host include a compromised immune system, underlying disease, recent surgery, increased age, and heavy smoking.

It is important to be able to culture Legionella from environmental specimens. Analysis of water suspected of being contaminated with Legionella identifies potential sources of the disease. Commonly sampled sources include non-potable water from cooling towers, condensers, whirlpools, etc. and potable water from water distribution systems, water heaters and tanks, drinking fountains and ice machines.

The organisms are nutritionally fastidious, non-spore forming, aerobic, gram-negative, slender rods. Media containing cysteine, yeast extract, α-ketoglutarate, and iron (BCYE) are required for isolation of Legionella. Selective BCYE (medium containing antibiotics), is recommended for specimens likely to be contaminated with other bacteria. Colonies gray-white to blue-green typically grow five days after incubation at 36ºC

The most common disease-causing member of the Legionellaceae family is Legionella pneumophila. This member has 16 named serogroups, all of which we can detect. Approximately half of the more than 60 named species of Legionella have been implicated in human disease. The methods and reagents used by Special Pathogens Laboratory can detect the primary disease-causing species and serogroups of Legionella. These methods include primary culture followed by latex agglutination and fluorescent antibody staining methods. If these classical identification methods are indeterminate, molecular sequencing methods can be used for further identification to the species level. This technology would identify any member of the family for which a nucleotide sequence is in GenBank.

The list of Legionella species implicated in disease and tested for using SPL methods and reagents:

  • L. pneumophila (serogroups 1–16)
  • L. dumoffii
  • L. micdadei
  • L. bozemanii (serogroup 1)
  • L. longbeachae (serogroups 1, 2)
  • L. jordanis L. feeleii (serogroup 1)
  • L. gormanii
  • L. wadsworthii
  • L. hackeliae
  • L. maceachernii
  • L. oakridgensis
  • L. cherrii
  • L. sainthelensi
  • L. anisa
  • L. parisiensis
  • L. spiritensis
  • L. jamestownensis
  • L. steigerwaltii
  • L. rubrilucens
  • L. erythra

Test Method
SPL modified ISO standards: 11731: 2017. Water Quality: Enumeration of Legionella

Turn Around Times
7–10 days (Test Code 101, 101-1L)
10-14 days (Test Code 101NY, 101NY-1L)

Test Codes
101NY – Samples from NY or CT
101NY-1L – Samples from NY or CT

Sample Transport
See Sampling and Shipping page for instructions.

Accreditations and Proficiency
See Accreditations and Proficiency page for information on our accreditations and Legionella testing proficiency programs.


QuickCheck and Case Investigation

QuickCheck, gives you the first look at Legionella culture results. Now, you can receive a preliminary report on the fourth business day after receipt in the laboratory. No more waiting, wondering, or calling about the trend of Legionella growth.

To add QuickCheck to your routinely processed samples, just check the box for QuickCheck on your chain of custody. Perfect for samples received on Monday, Wednesday, Thursday, Friday, or Saturday and only $75 per submission. Samples received Tuesdays are reported the following Monday.

Case Investigation
We understand the stress and anxiety that comes from having just one case of Legionnaires’ disease, so we’ve bundled everything you need from results to communication and support. Our case investigation processing and reporting includes the extra steps to expedite Legionella isolation. What’s more you get preliminary reporting, phone notification, results interpretation, and isolate storage. For a case investigation just check Case Investigation on your chain of custody. Cost: 15% + per sample.
If you have an outbreak, see our Outbreak Response services