Legionella was first
recognized following an outbreak of pneumonia among members of an American Legion
convention in 1976. The genus Legionella contains over 40 species with
about half being implicated in human disease. Legionella pneumophila is the
most common species isolated from infected individuals. The most frequent
manifestation of Legionella infection is pneumonia. This is a potentially
fatal pneumonia caused by the inhalation of water aerosols containing Legionella
bacteria into the lungs. Legionella bacteria are also responsible for an
epidemic non-pneumonic illness called Pontiac Fever. Pontiac Fever is an infection
characterized by high attack rates with fever and flu-like symptoms. It is a
self-limiting illness with the absence of pulmonary disease on chest x-rays.
Legionella is not contagious and transmissions to humans occur by inhalation of
Legionella organisms from contaminated water aerosols. It is generally
agreed that monitoring of water systems is warranted in order to identify the source of an
outbreak, evaluate biocides or to monitor areas where immunocompromised individuals are
present (hospitals). When monitoring is not routinely performed, aggressive
maintenance and disinfection procedures should be implemented. Institutions that
have prevention and monitoring programs should include hospitals, health care facilities,
industrial plants, hotels, schools and retirement communities.
Legionnaires’ Disease is an ever present
threat. Building owners and managers are faced with legal and financial
liabilities. Routing monitoring could be useful in establishing protocols should
legal complications occur.
Legionella Sampling
Swab of Faucet:
Allow water to briefly trickle through
opening to moisten outlet. Insert a sterile swab into the faucet and rotate four
times while moving swab upward into the opening. After collection, place swab into
transport system (transport culture swab.).
Optional – Allow hot water tap to run
and fill a sterile four ounce container (approximately 50-90 ml of water). Do after
initial swabbing of faucet.
Showerhead:
Allow water to trickle through opening (hot
water tap) for a few seconds – turn off and then collect swab sample by rotating swab
four times in a criss-cross pattern over the openings of the showerhead.
Place swab in transport system.
Hot Water Storage Tank:
Pre-flush samples – water samples are
collected from the drain valve located at base of large-volume storage tanks. Allow
water to flow from drain valve, and 40-90 ml is immediately collected in a sterile 4-oz.
container.
Optional Sample – wait 15-30 seconds
while water is flowing from drain valve and then collect another water sample from tank
(40-90 ml).
Cooling Towers; Reservoirs, etc.:
Collect sample of water from reservoir or
condensation pan using a sterile screw-capped container. Place container under
surface of water to obtain 2-90 ml sample.
Note: Avoid collecting excessive sediment. If collecting
samples from more than one reservoir, it is recommended that disposable gloves be worn and
changed after each sample.
Drinking Fountains, Whirlpools, Ice
Machines, etc.:
Insert sterile swab in outlet of the
fountain and place in transport system. Water may also be collected (40-90 ml).
Collect ice in sterile screw-capped
container.
Collect 40-90 ml of warm water from
whirlpool.
Place water sample in sterile screw-capped
containers.
Directions for Sending Legionella
Samples:
Label each sample clearly with Sample
Location, Date Collected and Sample Number.
Properly fill out all information on
Laboratory Request Form including Project Name and Contact Person.
Store swab and water samples in refrigerator
until transporting to the laboratory.
Ship samples in watertight containers with
cold packs included in cooler.
Ship to lab Monday through Friday and
(Saturday A.M. only) by express overnight delivery
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