Legionella. What is it and how do we treat it?

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Legionella.

What is it and how do we treat it?

2““Expect many Expect many enjoyable experiencesenjoyable experiences!”!”David M. ArmstrongDavid M. Armstrong

““Expect many Expect many enjoyable experiencesenjoyable experiences!”!”David M. ArmstrongDavid M. Armstrong

Legionella – What is it?Legionella – What is it?Legionella – What is it?Legionella – What is it?

• Type of bacteria found in bodies of water

• At least 39 species have been identified

• More than 60 serogroups have been identified

• Some serogroups have several subtypes



Legionella PneumophilaLegionella PneumophilaLegionella PneumophilaLegionella Pneumophila

• Most common species of all

• 15 serogroups

• Serogroup 1 has at least 50 subtypes

• Causes 85 to 90 percent of all cases



What is Legionaires’ Disease?What is Legionaires’ Disease?What is Legionaires’ Disease?What is Legionaires’ Disease?

• A multisystem illness with a deadly type of pneumonia

• Named by the press to identify the unknown bacterium



Legionaires’ DiseaseLegionaires’ DiseaseLegionaires’ DiseaseLegionaires’ Disease

• First identified – Bellevue-Stratford Hotel – Philadelphia, July of 1976

• Illness struck 221 people

• 72 who did not attend the convention

• 34 died



Did you know?Did you know?Did you know?Did you know?

• 2.4 million cases of pneumonia each year in the U.S.

• 10,000 to 100,000 are cases of Legionaires’ disease

• Only 1,000 to 3,000 are reported to CDC




• Cases go undetected due to lack of testing

• Other cases missed because test procedures are not sensitive enough

• Deaths from undetected cases classified as pneumonia with an unknown cause




• Most cases occur one or two cases at a time and not an outbreak

• Sporadic cases generally not reported to the public

• Overall opinion is that the problem is not that great




• Considered an environmental disease – water to people. Not communicable.

• Transmission occurs when airborne water droplets containing Legionella are inhaled



The Risk of Infection is Based on Two The Risk of Infection is Based on Two Key FactorsKey Factors

The Risk of Infection is Based on Two The Risk of Infection is Based on Two Key FactorsKey Factors

1. The number of bacteria reaching the body

2. The resistance of the individual



Legionella – Where does it come from?Legionella – Where does it come from?Legionella – Where does it come from?Legionella – Where does it come from?

• Poorly treated water

• Poorly designed plumbing systems

• Poorly treated plumbing systems



Primary Sources of Legionellae BacteriaPrimary Sources of Legionellae BacteriaPrimary Sources of Legionellae BacteriaPrimary Sources of Legionellae Bacteria

• Domestic Hot Water Systems

• Cooling Towers

• Evaporative Condensers

• Respiratory Care Equipment

• Showers



Primary Sources of Legionellae BacteriaPrimary Sources of Legionellae BacteriaPrimary Sources of Legionellae BacteriaPrimary Sources of Legionellae Bacteria

• Faucets

• Whirlpool Baths

• Humidifiers

• Fountains

• Grocery Store Produce Mister



Legionella – Where does it live?Legionella – Where does it live?Legionella – Where does it live?Legionella – Where does it live?

• Bacterial amplifiers

• Biofilm within plumbing systems

Storage Tank Storage Tank Feed-Back Feed-Back SystemSystemStorage Tank Storage Tank Feed-Back Feed-Back SystemSystem

Heated Water SafetyReliefValve

Recirculated Water Make Up Water

Storage Tank

Liquid or GasFilled Bulb

CondensateReturn

V.B.

F&TTrap

TemperatureReg Valve

SteamSupply

P

Thermo-meterTemperature signal

is “fed back” throughcapillary tube

Recirculatin Pump



Legionellae and TemperatureLegionellae and TemperatureLegionellae and TemperatureLegionellae and Temperature

• Below 68°F legionellae can survive but are dormant

• Legionellae growth range (68°F – 122°F)

• Ideal growth range (95°F – 115°F)

• Above 122°F legionellae can survive but do not multiply

• At 131°F legionellae die within 5 to 6 hours

• At 140°F legionellae die within 32 minutes

• At 151°F legionellae die within 2 minutes

• Disinfection range (158°F - 176°F)



Preventive MeasuresPreventive MeasuresPreventive MeasuresPreventive Measures

• Maintain mechanical and plumbing systems for the control of Legionella

• If you are high risk for Legionella consider more costly measures to fix your systems and reduce the risks

• Document all preventive measures to show you took responsible action



Environmental SamplingsEnvironmental SamplingsEnvironmental SamplingsEnvironmental Samplings

• CDC does not recommend regular water sampling

• Negative results may create a false sense of security and positive results a false alarm

• Sampling results, though sometime inconclusive, provide lifesaving information



Samplings – Yes or No?Samplings – Yes or No?Samplings – Yes or No?Samplings – Yes or No?

• Weigh value of information provided against the cost

• Weigh the risk of misleading sampling against the risk of not sampling

• Consider risk management

• DO NOT use as a substitute for preventive measures



Methods of System TreatmentMethods of System TreatmentMethods of System TreatmentMethods of System Treatment

• Superheat and Flush (thermal)

• Feed-Forward Instantaneous Water Heaters (thermal)

• Hyperchlorination (biocide)

• Ultra Violet Rays (biocide)

• Ozone (biocide)

• Chlorine Dioxide (biocide)

• Copper/Silver Ionization (biocide)



Superheat & Flush PositivesSuperheat & Flush PositivesSuperheat & Flush PositivesSuperheat & Flush Positives

• Inexpensive

• Proven effective irrespective of water quality

• Non aggressive to pipe work and fittings

• Non toxic/consumable

• No professionally qualified personnel required to administer treatment



Superheat & Flush NegativesSuperheat & Flush NegativesSuperheat & Flush NegativesSuperheat & Flush Negatives

• Potential scald risk

• Non-effective unless sterilization temperature is achieved (biofilm)

• Dead-legs may not permit adequate flushing



Temperature/Time Burn ChartTemperature/Time Burn ChartTemperature/Time Burn ChartTemperature/Time Burn Chart

Temperature in F°

111.2

116.6

118.4

122.0

131.0

140.0

149.0

158.0

Time for 1st degree burn

5 hours

35 minutes

10 minutes

1 minute

5 seconds

2 seconds

1 second

------



What types of Water Heaters are on the What types of Water Heaters are on the market today?market today?

What types of Water Heaters are on the What types of Water Heaters are on the market today?market today?

• Feed-Back Units: Operate on a differential of water TEMPERATURE

• Feed-Forward Units: Operate on a differential of water PRESSURE

Storage Tank Storage Tank Feed-Back Feed-Back SystemSystemStorage Tank Storage Tank Feed-Back Feed-Back SystemSystem

Heated Water SafetyReliefValve

Recirculated Water Make Up Water

Storage Tank

Liquid or GasFilled Bulb

CondensateReturn

V.B.

F&TTrap

TemperatureReg Valve

SteamSupply

P

Thermo-meterTemperature signal

is “fed back” throughcapillary tube

Recirculatin Pump

Feed-ForwardFeed-Forward Instantaneous Water Heater Instantaneous Water HeaterControl Valve SchematicControl Valve Schematic


TubeTubeBundleBundle

MixingChamber

Valve #1

Valve #2

Valve #3

Supply Water In @ P1

Blended Water Out @ P2

P1

P2

“Over-heated”Water fromtube bundle



Feed-ForwardFeed-Forward Instantaneous Water Instantaneous Water Heater PositivesHeater Positives


• Sterilizes water in the heat exchanger as a function of making hot water



TubeTubeBundleBundle

MixingChamber

Valve #1

Valve #2

Valve #3

Supply Water In @ P1

Blended Water Out @ P2

P1

P2

“Over-heated”Water fromtube bundle





• Sterilizes water in the heat exchanger as a function of making hot water

• Non aggressive to pipe work and fittings

• Non toxic/consumable

• No scald risk



Feed-ForwardFeed-Forward Instantaneous Water Instantaneous Water Heater NegativesHeater Negatives

Feed-ForwardFeed-Forward Instantaneous Water Instantaneous Water Heater NegativesHeater Negatives

• Water which bypasses the heat exchanger is not sanitized

• Does not kill bacteria in the system biofilm



Hyperchlorination PositivesHyperchlorination PositivesHyperchlorination PositivesHyperchlorination Positives

• Inexpensive

• Effectively kills bacteria in the water



Hyperchlorination NegativesHyperchlorination NegativesHyperchlorination NegativesHyperchlorination Negatives

• Hazardous material which requires trained operators in order to handle

• The chemical is a carcinogen

• Aggressive to pipe work and fittings

• Does not kill bacteria in the biofilm



Ultra Violet PositivesUltra Violet PositivesUltra Violet PositivesUltra Violet Positives

• Harmless and non-toxic




Ultra Violet NegativesUltra Violet NegativesUltra Violet NegativesUltra Violet Negatives

• Expensive

• Only effective at point of treatment

• High maintenance cost – lamps wear out and are fragile and need replacement

• Micro organisms can become resistant and repair UV damage

• Does not kill the bacteria in the biofilm



Ozone PositivesOzone PositivesOzone PositivesOzone Positives




Ozone NegativesOzone NegativesOzone NegativesOzone Negatives

• Difficult to maintain effective levels of ozone in the system – decomposes into water

• High ozone levels may damage pipe

• Not tested in facilities – its use would be pioneering

• Does not kill the bacteria in the biofilm



Chlorine Dioxide PositivesChlorine Dioxide PositivesChlorine Dioxide PositivesChlorine Dioxide Positives


• Early indications show potential of killing bacteria in the biofilm as well as removal of biofilm



Chlorine Dioxide NegativesChlorine Dioxide NegativesChlorine Dioxide NegativesChlorine Dioxide Negatives

• Expensive

• Concentration levels required often exceed health standards – health & safety issues

• Aggressive to copper piping

• Needs special storage – hazardous material

• Chemical (Potassium, Chlorate and Hydrochloric Acid) is unstable – may explode

• Professionally qualified personnel required



Copper/Silver Ionization PositivesCopper/Silver Ionization PositivesCopper/Silver Ionization PositivesCopper/Silver Ionization Positives

• Use of sacrificial anodes produce ions that kill Legionellae bacterial in the water

• Ions also kill bacteria in the biofilm



Copper/Silver Ionization NegativesCopper/Silver Ionization NegativesCopper/Silver Ionization NegativesCopper/Silver Ionization Negatives

• Expensive

• Constant monitoring of ion levels

• Sacrificial anodes need regular replacement

• Ion levels can become toxic if they accumulate

• Professionally qualified personnel required



Questions?Questions?Questions?Questions?

Legionella. What is it and how do we treat it?

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