where to sample?. objectives environmental sources of legionella determine sources to sample tools...
TRANSCRIPT
Where to Sample?
Objectives
Environmental Sources of Legionella
Determine Sources to Sample
Tools Needed for Sampling
How to Sample
Legionella Transmission Legionella transmission is via aerosols
— the inhalation of mist droplets containing the bacteria. Common sources include cooling towers, swimming pools, domestic hot-water systems, fountains, and similar disseminators that tap into a public water supply. Natural sources of Legionella include freshwater ponds and creeks.
Host
Aerosolized Droplets
Source
Conditions Favorable for Legionella Water Temperature 68°- 122°F (20°-
50°C) Area where water can become stagnant
and formation of a bio-film can occur. Total Chlorine Residual below .5ppm Lack of routine maintenance and
cleaning of cooling towers, decorative fountains and recreational water facilities.
Common Sources
Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere.Common applications include cooling the
circulating water used in oil refineries, chemical plants, power stations and building cooling.
Common Sources
Swimming Pools
Hot Tubs
Domestic Hot Water Systems
Decorative Fountains
Natural Sources
Freshwater Ponds
Freshwater Creeks
Single Case Investigation v/s Outbreak Investigation
Single Case Investigation
Outbreak Investigation
Outbreak Environmental InvestigationNot a Routine Inspection For Legionella
Ask facility to shut off decorative fountains – but advise them not to clean or drain the fountain.
Ask the facility to close all recreational water facilities (for use by the public)on site – advise them not to super chlorinate, clean, or change/disturb any of the filter systems.
Staff needed for Environmental Assessment for
Legionella Outbreak Investigation LHD/WVDHHR/CDC
LHD StaffDIDE StaffCDC StaffOEHS District
EngineersOEHS District
SanitariansOEHS Central Office
Staff
Facility/Private Industry StaffFacility(s)
ManagementFacility(s)
Maintenance StaffCertified Pool
OperatorOther Facility Staff
Use the Legionellosis Hypothesis Generating Questionnaire and the Sample Environmental Assessment of Water Systems Form.
CDC Sample Environmental Assessment of Water Systems
Determine Where to SampleIn consultation with DIDE and CDC What type of facility? Are there any decorative fountains,
misters or other aerosol-generating devices anywhere on the facility premises?Are the decorative fountains chlorinated –
with a positive feed chlorinator? Has the facility previously associated
legionellosis cluster or outbreak?
Determine Where to SampleIn consultation with DIDE and CDC Does the facility have and recreational
water facilities? If so how many and what types.Filter type and maintenance recordsDisinfection type and recordsCleaning and maintenance schedule(s)
Determine Where to SampleIn consultation with DIDE and CDC What type of potable water supply? Potable water supply maintenance
Specifics of the potable water supply○ Hot water temperature(s)○ Chlorine residual(s)○ Interruptions in the potable water supply
Any construction or additions to potable water supply?
Where do we need to sample? Potable water supply
Recreational Water Facilities
Aerosol – Generating Devices i.e. decorative fountains, misters, etc.
○ After consultation with DIDE and CDC
Where do we send the samples?
Samples will be sent to the lab designated by CDC
After consultation with DIDE and CDC
For assistance with collecting water samples contact Office of Environmental Health Services.
What tools do you need for proper sampling? Sterile 1 liter sample bottles Sodium thiosulphate Sterile polyester swabs Sterile sample tubes Pipette/Dropper for measuring sodium
thiosulphate Thermometer pH test kit or test strips Chlorine test kit Cooler for sample storage and shipping Sample collection log
Control Sample For each sample: using a separate
control sample collected at the same timepH readingTemperatureTotal Chlorine ResidualRecord this data on a log which also includes :
a sample ID, date collected, time collected, sample type, sample description and comments include the name of person sampling.
Example Sample Collection Log
TAKING THE TEMPERATURE TOTAL CHLORINE RESIDUALAND pH OF EACH CONTROL SAMPLE
Sample Collection Water Sample
One (1) liter water sample Bio-film sample
Taken from shower heads, faucet aerators, scum line on fountains and recreational water facilities.
Sample: Potable Water, Recreational Water Facilities, Decorative Fountains, and Cooling Towers
Where to obtain Bio-film sample from scum line
Potable Water Sampling Collect water samples from the distal
point(s) of the potable hot water. Collect water sample(s) from sleeping
room(s) and any restroom as indicated from the investigation.Water Sample(s) and Bio-film sample(s)
take from showers and faucets.Sample(s) taken from the Hot Water
Heater(s) that serve the area of facility identified.
Taking a Bio-film Sample from the Shower Head and Faucet Aerator
Sampling - Swimming Pools/Hot Tubs or Other Recreational Water Facilities – Outdoor and Indoor In addition to water sample and scum
line bio-film sampleCollect sample from sand filter or sample cut
from cartridge filterBio-film from other area of the recreational
water facility where a bio-film may form.
Other areas where a Bio-Film may be found.
Sampling - Cooling Towers Cooling Towers associated with the
HVAC system on the site. Commercial Industrial Cooling Towers in
the area.○ Note: Ask about the use of biocides
Sampling and Findings
Northern Panhandle Legionella Cluster – Environmental Sampling – Facility A
Sampled the potable water system of Facility A– hot water heater, distal points of potable water system, sleeping rooms and restrooms as indicated by the questionnaires of patients.
Sampled all recreational water facilities at Facility A.
Sampled all decorative fountains at Facility A .
Northern Panhandle Legionella Cluster – Environmental Sampling – Cooling Towers
Sampled cooling towers at three (3) industrial facilities in close proximity to Facility A .
Oil RefineryOxygen and Argon gas production facility Recycling facility.
Water Sample Results - CDC Legionella pneumophila serogroup 1
only one facility grew this serogroup○ However, this is a common strain and isolation from the
cooling tower does not definitively implicate this facility as the source of the outbreak.
○ In fact, our epidemiology indicates that only three (3) of the community cases lived or visited within a 10 mile radius of the facility during their incubation period.
Facility Date Collected Date processed Sample description Organism
1 9/08/2011 9/10/2011 Biofilm from Cooling tower
Legionella (Not Lp1) andLegionella pneumophila serogroup 1, (MAb[2] negative)
2 9/08/2011 9/10/2011 Water from pump room Legionella (Not Lp1)
3 9/08/2011 9/10/2011 Biofilm and water from cooling tower
None isolated
4 9/09/2011 9/10/2011 Water from cooling tower
Legionella (Not Lp1)
Problems Encountered Decorative Fountains had been super
chlorinated prior to sampling. Recreational Water Facilities had been
super chlorinated prior to sampling. Cartridge Filters for hot tubs had been
replaced. Shower heads were a sealed unit –
could not obtain a bio-film from sprayer.
QUESTIONS?
Judy Vallandingham R.S.
General Sanitation Program Manager
Office of Environmental Health Services – Public Health Sanitation
304-356-4341
Sources CDC Procedures for the Recovery of
Legionella from the Environment. CDC Sample Environmental Assessment
of Water Systems http://www.cdc.gov/legionella/files/EnvironmentalAssessmentInstrument.pdf
ASHREA STANDARD 12-2000: Minimizing the Risk of Legionellosis Associated with Building Water Systems.
Training with CDC.