GTS Legionella Water Testing Lab

For 33 years, GTS has been testing for Legionella spp. in water samples from cooling towers and potable water world-wide. This began when the U. S. Centers for Disease Control and Prevention began referring companies to us for environmental water Legionella testing.

GTS Legionella Laboratory
RICHARD W GILPIN PHD LTD
Email gilpin@legionella.com
Cellphone (410) 961-6638

We recommend routine testing of warm water-containing equipment that may produce aerosols that contain Legionella bacteria, as does the United States Capitol and the State of Maryland.

The ultimate measure of microbial viability and biological activity is growth in some form of culture system. Unfortunately, due to many limitations, culture of Legionella is usually not the most sensitive or rapid detection method.
Our CDC quantitative test method was developed by our certified microbiologist laboratory director during research collaboration with CDC in 1979 and was published in Water Research 1985 and Proceedings of the 49th International Water Conference, Pittsburgh, PA in October 1988 "Quantitation of Legionella pneumophila in One Thousand Commercial and Industrial Cooling Towers."

GTS test reports provide quantitative numbers of Legionella clinically associated with Legionnaires' Disease including 14 serogroups of Legionella pneumophila and 15 other Legionella species (L. anisa, L. bozemanii sg 1 & 2, L. dumoffi, L. feeleii sg 1 & 2, L. gormanii, L. hackeliae sg 1 & 2, L. jordanis, L. longbeachae sg ! & 2, L. maceachernii, L. micdadei, L. oakridgensis, L. parisiensis, L. sainthelensi, L. santicrucis, and L. wadsworthii).

For more information about testing for Legionella, go to Legionella 2003: An Update and Statement by the Association of Water Technologies (AWT).

Question: How do our test results compare to culture results?
Answer: Much faster: DFA results in minutes; Culture results in 10 to 14 days with confirmation by DFA.
Our test method produces quantitative results with environmental samples that are 10-fold to 100-fold more sensitive than culture.
We use a modification of the original CDC test method; direct fluorescent monoclonal antibody (DFA) epifluorescence microscopy.
Our test result of no Legionella observed (<10/ml) is equivalent to a culture result of <0.1/ml to <1.0/ml, assuming that the culture procedure is properly performed and validated by the DFA monoclonal antibody test.

Question: Why do we use the direct fluorescent antibody (DFA) method?
Answer: Because we can identify non-culturable Legionella that can cause outbreaks.
Non-culturable, viable Legionella have been reported in several peer-reviewed journals, for example, Acta Pathologica, Microbiologica et Immunologica Scandinavica 113:45-53, 2005.
Only DFA tests performed by trained laboratory personnel can identify these Legionella.
Direct fluorescent antibody (DFA) tests using a battery of monoclonal antibodies have proven to be more sensitive and reliable with environmental water samples.

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