ATTACHMENT J _ RISK ASSESSMENT - ENVIRONMENTAL WATER SAMPLING PROTOCOL.pdf

ATTACHMENT J – RISK ASSESSMENT - ENVIRONMENTAL WATER SAMPLING

PROTOCOL

1) The ICC will determine when environmental samples are to be collected based upon the need for routine environmental risk assessment, mitigation or nosocomial cases.

2) Vendor is responsible for the collection of the environmental samples under direction of

Engineering Service.

3) Once collected, samples are to be processed by a testing laboratory with experience in microbial testing of potable water.

a) The environmental testing laboratory will meet, at least, the minimal requirements for state-certified competency of microbial testing of potable water and is proficient at performing the culture of Legionella species from environmental samples

b) Samples need to be cultured for Legionella pneumophila.

c) The laboratory must be capable concentrating water samples prior to plating the samples on selective media to increase the sensitivity of the assay (see subpar.5k of the Directive). A limit of detection of ten colony forming units per milliliter is recommended for the culture of Legionella from water samples.

d) If there is a possibility that the facility will need molecular characterization of environmental Legionella isolates, the laboratory should be able , at least, temporarily store the isolates appropriately.

e) Vendor under direction of the Engineering Service in collaboration with Pathology and

Laboratory medicine Service, is responsible for ensuring that the samples are transferred to the environmental testing laboratory and recording the results from the testing. Any positive results will be reported to the ICC.

4) Location of water samples in the water distribution system.

a) Distal water sites. Distal water sites are the points in the water distribution system where the end user (e.g., patient) comes in contact with the water (e.g., faucets and showers).

i) Distal water sites are sampled any time environmental sampling is needed in the course of implementing the facility Legionella evaluation plan (e.g., for routine environmental surveillance, or for monitoring of an Action Plan mitigation effort).

ii) At least ten distal water sites at the facility

iii) Considerations when selecting site numbers and locations include:

iv) If environmental testing is initiated due to a suspected HCA LD case, samples from distal sites in the immediate vicinity of the case should be included in the samples collected.

v) Sampling includes sites from high risk areas (e.g., hematology-oncology areas, medical unit).

b) Hot Water Tanks (HWT). If the facility needs to implement environmental water testing to monitor an Action Plan mitigation effort (e.g., due to a prior history of epidemiologically-linked HCA LD or positive environmental screening results), then it is recommended that two samples are taken from each HWT in addition to testing at least ten distal water sites.

5) Collecting samples from distal sites.

a) Options for sample collection methods include collecting a volume of water at each distal site or collecting swab samples at each distal site.

b) The ID/ICC will need to determine if it is appropriate to collect water and/or swab samples.

Considerations include whether the samples are for routine environmental screening or for a case investigation, ability to collect the samples, and the transport of the samples to the testing laboratory. Prior to sampling, it would be prudent to consult with the environmental testing laboratory for requirements and/or recommendations on sample collection and shipping. NOTE: Optimal sensitivity is desirable in the context of a case investigation (e.g., that results from clinical screening). Therefore, consideration needs to be given to collecting both water and swab samples from the water outlets in the immediate environment of a suspected case.

c) The following procedure is recommended for distal site water sampling:

ii) Turn on the hot water faucet.

iii) Immediately fill a specimen container with a minimum of 100 milliliters (ml) of water.

NOTE: If the testing laboratory requires a larger sample volume, follow their recommendations.

iv) Label container with location and “immediate sample”.

v) Refrigerate samples at 2-8°Celsius (C) until processing.

d) The following procedure is recommended for distal site swab sampling:

ii) Remove aerator, if present.*

iii) Moisten the distal site outlet by allowing water to trickle through the opening.

iv) Remove a sterile swab from its transport container. Insert the swab into the outlet and rotate four times around the inner circumference and moving up the faucet as far as the swab will reach.

v) For showerheads, rotate the swab over the entire surface of the showerhead four times.

vi) Replace the swab into the container.

vii) If no liquid media is in the swab container, add a few mls of water from the sample source.

viii) Label the swab container with the sample location.

6) Collecting water samples from HWTs. It is recommended that two samples be taken from each

HWT as follows:

a) Open the drain valve and immediately fill one specimen container with 100 ml of water.

Label the container with the sample location and “HWT 1st sample”

b) Allow the water to flow for approximately 30 seconds to 1 minute. Fill a second specimen container with 100 ml of water. Label the container with the sample location and “HWT 2nd sample”

NOTE: These samples represent both the tank contents and the residual water within the drainpipe. L. pneumophila is often recovered from samples which contain sediment (scale);

however, thick rusty sediment can actually inhibit Legionella growth.

c) All samples will be refrigerated at 2-8°C until processing.

* The vendor will remove and replace aerator, screen, shower head, etc. at needed to collect samples.