Presentation on theme: "Where to Sample?. Objectives Environmental Sources of Legionella Determine Sources to Sample Tools Needed for Sampling How to Sample."— Presentation 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.atmosphere Common applications include cooling the circulating water used in oil refineries, chemical plants, power stations and building cooling.oil refineries chemical plantspower stations
Common Sources Swimming Pools Hot Tubs Domestic Hot Water Systems Decorative Fountains
Single Case Investigation v/s Outbreak Investigation Single Case Investigation Outbreak Investigation
Outbreak Environmental Investigation Not 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 Staff DIDE Staff CDC Staff OEHS District Engineers OEHS District Sanitarians OEHS Central Office Staff Facility/Private Industry Staff Facility(s) Management Facility(s) Maintenance Staff Certified Pool Operator Other 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 Sample In 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 Sample In consultation with DIDE and CDC Does the facility have and recreational water facilities? If so how many and what types. Filter type and maintenance records Disinfection type and records Cleaning and maintenance schedule(s)
Determine Where to Sample In 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 time pH reading Temperature Total Chlorine Residual Record 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 RESIDUAL AND 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 sample Collect sample from sand filter or sample cut from cartridge filter Bio-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 Refinery Oxygen 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. FacilityDate CollectedDate processedSample descriptionOrganism 19/08/20119/10/2011Biofilm from Cooling tower Legionella (Not Lp1) and Legionella pneumophila serogroup 1, (MAb negative) 29/08/20119/10/2011Water from pump roomLegionella (Not Lp1) 39/08/20119/10/2011Biofilm and water from cooling tower None isolated 49/09/20119/10/2011Water 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
Sources CDC Procedures for the Recovery of Legionella from the Environment. CDC Sample Environmental Assessment of Water Systems mentalAssessmentInstrument.pdf ASHREA STANDARD : Minimizing the Risk of Legionellosis Associated with Building Water Systems. Training with CDC.