Transcript Control of Legionella and Legionnaires’ Disease

What’s New in
Legionnaires’ Disease?
How does it relate to your job?
Legionella bacteria
Richard D. Miller, Ph.D.
www.estechlab.com
Legionella Live in Water

Surface water (lakes, streams, etc)
• Virtually all have Legionella
• Low numbers - rare disease
Actually, Legionella live
inside of amoebae and
other protozoa that live in
the water
Legionella Live in Water

Surface water (lakes, streams, etc)
• Virtually all have Legionella
• Low numbers - rare disease

Thermal areas (i.e. near hot springs)
• Elevated numbers – rare disease
Legionella Live in Water

Surface water
• Virtually all have Legionella
• Low numbers - rare disease

Thermal areas
• Elevated numbers
• Rare disease

Building water
• May have high levels of Legionella
•Airborne dissemination
• Legionnaires’ disease
Hospital- nosocomial LD
Other buildings- community-acquired LD
Hotel- travel-associated LD (Europe)
EWGLI-NET (37 countries)
Most cases are single isolated events,
and the source is never determined
Legionella- are they all equally bad?

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Large family of at least 50 species (likely >80 species)
Do they all cause disease?
L. pneumophila – >90% of disease in U.S./Europe
• > 14 serogroups (serogroup 1 most common)
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Other species- unusual, except in transplant hospitals
How does this relate to your job?
•Some guidelines and standards view all Legionella the same
and have set limits based on total Legionella
•New VA Hospital guidelines- Non-transplant hospitals only
monitor for L. pneumophila!
• Thus, unless it is a hospital, ESTech considers the risk for
L. pneumophila to be 10-fold greater than with other species.
Legionnaires’ Disease
There are still large outbreaks!

Most of the estimated 25,000 cases in
the U.S. each year are single isolated
cases.

Multi-case outbreaks still occur each
year in the U.S. and the world
Recent Outbreaks- International

Netherlands (1999) – flower/home show Jacuzzi
• 250 cases, 28 deaths

Melbourne, Australia (2000) – public aquarium cooling tower
• 113 cases, 2 deaths

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(4%)
Harnes, France (2003) – cooling tower
• 86 cases, 18 deaths

(2%)
Barrow, UK (2002) – cooling tower
• 179 cases, 7 deaths

(2%)
Spain (2001, 2006) – cooling towers
• 2001 (Murcia) 449 confirmed case (>600 total), 6 deaths
• 2006 (Pamplona) 139 confirmed case, 0 deaths (0%)
Hiuga City, Japan (2002) – public hot spring bath
• 295 cases, 7 deaths

(11%)
(21%)
Norway (2005) – air scrubber
– 55 cases, 10 deaths
(18%)
(1%)
Recent Outbreaks- North America

Toronto, Canada (2005) – nursing home, cooling tower
• >110 cases, 20 deaths (patients only) (18%)
• 71 patients, 23 staff, 14 visitors, 2 neighborhood residents
Recent Outbreaks- North America

Toronto, Canada (2005) – nursing home, cooling tower
• >110 cases, 20 deaths (patients only) (18%)
• 71 patients, 23 staff, 14, visitors, 2 neighborhood residents

Rapid City, South Dakota (2005) – restaurant, decorative fountain
• 19 cases, 1 death (5%)
• Mayor of Rapid City was
one of the victims!

Recent Outbreaks- North America

Toronto, Canada (2005) – nursing home, cooling tower
• >110 cases, 20 deaths (patients only) (18%)
• 71 patients, 23 staff, 14, visitors, 2 neighborhood residents

Rapid City, South Dakota (2005) – restaurant, decorative fountain
• 19 cases, 1 death (5%)
• Mayor of Rapid City was
one of the victims!

San Antonio, TX (2006) – hospital, likely cooling tower
• At least 10 cases, 3 deaths
• 5 patients, 5 visitors
(30%)
How does this relate to your job?
Bad publicity for you and your clients
Recent Outbreaks- North America

Toronto, Canada (2005) – nursing home, cooling tower
• >110 cases, 20 deaths (patients only) (18%)
• 71 patients, 23 staff, 14 visitors, 2 neighborhood residents
Bad financially for you and your clients
$600 million class action lawsuit!
Outbreak in 1994
50 cases, 1 death
2006, Federal jury verdict- $193 million
against Essef Corp (spa filter manufacturer)
awarded to Celebrity Cruise.
Outbreak in 1994
50 cases, 1 death
2007, Federal District Court overturned all
but $10 million of the award
Britain’s Worst LD Outbreak
Barrow Arts Center- 2002
179 cases (perhaps 500 more), 7 deaths
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Tried on 7 counts of manslaughter
for failing to have a contract for
treating the Arts Centre cooling
tower
Acquitted by a jury, but fined
£15,000 for breach of health and
safety laws
Barrow Borough Council was
fined £125,000
Gillian Beckingham
Architect
Head of Design Services for
the Barrow Borough Council
Britain’s Worst LD Outbreak
Barrow Arts Center- 2002
179 cases (perhaps 500 more), 7 deaths


Tried on 7 counts of manslaughter
for failing to have a contract for
treating the Arts Centre cooling
tower
Acquitted by a jury, but fined
£15,000 for breach of health and
safety laws
Barrow Borough Council was
fined £125,000
This can be prevented!

Gillian Beckingham
Architect
Head of Design Services for
the Barrow Borough Council
Legionnaires Disease Prevention

Legionella Guidelines
• VHA - Prevention of Legionella Disease, 2008
• WHO - Legionella and the Prevention of Legionellosis, 2007
• CDC - Guideline for Prevention of Nosocomial Pneumonia, 2003
- HICPAC Guideline for Environmental Infection Control in
Healthcare Facilities, 2001
• State of Maryland (hospitals), other states
• Pittsburgh / Allegheny County (hospitals)
• Professional Organizations
 ASHRAE (American Society of Heating, Refrigerating, and
Air-Conditioning Engineers) - 2000
 AWT (Association of Water Technologies)- 2003
 CTI (Cooling Technology Institute) - 2006
Legionnaires Disease Prevention

Legionella Guidelines
Problems
 No widespread implementation of any of
these guidelines
 No agreement on what to do, including
whether to monitor for Legionella and how to
interpret the results.
Legionnaires Disease Prevention
What’s new?
Legionella Risk Management
Defined process with specific steps
 Similar to HACCP that has been successful in
the food industry

• Hazard Analysis Critical Control Point
 Framework for the new WHO document (2007)
“Legionella and Prevention of Legionellosis”
Legionnaires Disease Prevention
What’s new?
Legionella Risk Management
Defined process with specific steps
 Similar to HACCP that has been successful in
the food industry

• Hazard Analysis Critical Control Point
 Framework for the new WHO document (2007)
“Legionella and Prevention of Legionellosis”
and the new ASHRAE Standard (in preparation)
Legionnaires Disease Prevention
What’s new?
Legionella Risk Management
Defined process with specific steps
 Similar to HACCP that has been successful
in the food industry

• Hazard Analysis Critical Control Point
 Format for the new WHO document (2007)
“Legionella and Prevention of Legionellosis”
and the new ASHRAE Standard (in preparation)
Legionnaires Disease Prevention
Legionella Risk Management
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Identify all uses for and occurrences of water at a
facility and prepare process flow diagrams
Conduct a hazard analysis (i.e. Legionella)
Identify critical control points in the process to
eliminate or control the hazard and implement the
controls
Describe the critical limits for the hazard
Establish a monitoring plan to validate the control
measures
Legionnaires Disease Prevention
Legionella Risk Management


Identify all uses for and occurrences of water at a
facility and prepare process flow diagrams
Conduct a hazard analysis (i.e. Legionella)
Building Water Use Assessment –
Legionella Hazard
 Cooling towers and evaporative condensers
Recent Outbreaks- International

Netherlands (1999) – flower/home show Jacuzzi
• 250 cases, 28 deaths

Melbourne, Australia (2000) – public aquarium cooling tower
• 113 cases, 2 deaths

(11%)
(2%)
Murcia, Spain (2001) – cooling tower
• 449 confirmed case (>600 total), 6 deaths

Hiuga City, Japan (2002) – public hot spring bath
• 295 cases, 7 deaths

(4%)
Harnes, France (2003) – cooling tower
• 86 cases, 18 deaths

(2%)
Barrow, UK (2002) – cooling tower
• 179 cases, 7 deaths

(1%)
(21%)
Norway (2005) – air scrubber
– 55 cases, 10 deaths
(18%)
Recent Outbreaks- North America

Toronto, Canada (2005) – nursing home, cooling tower
• >110 cases, 20 deaths (patients only) (18%)
• 71 patients, 23 staff, 14 visitors, 2 neighborhood residents
• Already a $600 million class action law suit against the nursing home
Lidköping, Sweden


Community-acquired vs nosocomial disease
Community-acquired disease
•
•
•
•
Point source epidemics – cooling towers, Jacuzzis
Inhalation of infectious aerosols
People have been infected as far as 6 miles from the source!!
Very large numbers of Legionella in the contaminated water
•32 cases from industrial cooling tower
•1 km from town
•Unusual wind direction
Building Water Use Assessment –
Legionella Hazard
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Hot tubs and Jacuzzis
Building Water Use Assessment –
Legionella Hazard
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Hot tubs and Jacuzzis
50 cases, 1 death
Recent Outbreaks- International

Netherlands (1999) – flower/home show Jacuzzi

• 250 cases, 28 deaths (11%)
Melbourne, Australia (2000) – public aquarium cooling tower
• 113 cases, 2 deaths

(2%)
Murcia, Spain (2001) – cooling tower
• 449 confirmed case (>600 total), 6 deaths
(1%)

Hiuga City, Japan (2002) – public hot spring bath

• 295 cases, 7 deaths (2%)
Barrow, UK (2002) – cooling tower
• 179 cases, 7 deaths

Harnes, France (2003) – cooling tower
• 86 cases, 18 deaths

(4%)
(21%)
Norway (2005) – air scrubber
– 55 cases, 10 deaths
(18%)
Building Water Use Assessment –
Legionella Hazard

Potable water (hot water tanks, faucets)
Buildings with hot water temperature less than 124° F (51° C)
•The most prominent source in hospital patients
•Chronic colonization of the potable water system
Building Water Use Assessment –
Legionella Hazard

Cooling towers and evaporative condensers
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Potable water (hot water tanks, faucets, showers)
Hot tubs and Jacuzzis
Indoor decorative fountains
Humidifiers, mister systems
Industrial process water
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Legionnaires Disease Prevention
Legionella Risk Management



Identify all uses for and occurrences of water at a
facility and prepare process flow diagrams
Conduct a hazard analysis (i.e. Legionella)
Identify critical control points in the process to
eliminate or control the hazard and implement
the controls Cooling Towers - Biocide Use
Which biocides work best against Legionella?
Cooling Tower Biocide Study
1998-2004
Published in ASHRAE Transactions in 2006
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2,590 water samples were collected by chemical treatment
personnel from ~1,000 different cooling towers throughout
the U.S. (primarily eastern U.S.)
Samples were to be collected prior to any slug dosing of
biocides (biocide control at its lowest)
Samples were shipped overnight to our lab for analysis:
Legionella culture (limit of sensitivity was 10 cfu/ml)
Specific biocides, concentration and dosage schedule were
chosen entirely by chemical treatment representatives as
part of their normal maintenance.
Cooling Tower Biocides
8 different biocides alone or in combination
28 different combinations

Non-Oxidizing biocides
•
•
•
•
•
•
Quat
Carbamate
Isothiazolinone
Brominated nitrilopropionamide (DBNPA)
Glutaraldehyde
Tetrakis(hydroxymethyl)phosphonium sulfate (THPS)
 Oxidizing biocides
• Sodium bromide + trichlorisocyanuric acid
• Hydroperoxide
Data Analysis

Each of the 28 treatments compared to the overall
prevalence in all of the towers (n=2,590):
Legionella prevalence (>10/ml)- 13% (±1)
High Legionella (>1,000/ml) prevalence- 2% (±1)
Question- Which biocide combinations were statistically
better or worse than average?
Prevalence of Legionella in Towers with:
Bromine (n=572)
Legionella (%±CI)
Bromine alone
+ quat
+ carbamate
+ isothiazolinone
+ glutaraldehyde
+ DBNPA
+ THPS
Total bromine
Overall average
30/130 (23±7)
5/135 (4±3)
4/36 (11±8)
21/128 (16±6)
21/103 (20±7)
8/19 (42±22)
0/21 (0±16)
89/572 (16±3)
626/2590 (13±1)
High Legionella (%±CI)
6/130 (5±3)
1/135 (1±4)
1/36 (3±12)
3/128 (2±5)
7/103 (7±4)
(0±18)
0/21 (0±16)
18/572 (3±1)
0/19
106/2590 (2±1)
Summary
General Conclusions

Many different biocide combinations worked well
to control Legionella colonization.

There was no magic bullet. None of the biocide
combinations was always effective in preventing
Legionella colonization and none always failed.

Combinations of two non-oxidizing biocides were
usually just as good, and frequently better, than
an oxidizing/non-oxidizing combination.
Summary
Legionella-Biocide Trends

THPS- significantly more effective than most of the other
biocide combinations tested.

Bromine- combinations with Quats and THPS were
better than average, but other combos trended toward
more prevalent Legionella.

Quats- as effective as other biocides in most
combinations (contrary to popular opinion). The
quat/bromine was better than average.

DBNPA- statistically worse than the other non-oxidizing
biocides
Please keep sending biocide information!!
New Biocide Data
High Pe r for m ance Biocide s
Legionella Prevalence (% Positive)
24.0
22.0
20.0
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
THPS & Glutaraldehyde
Quat & Glutaraldehyde
THPS
THPS & Isothiazoline
THPS & Carbamate
Bromine& Quat
Quat & Isothiazoline
Quat & Hydrope roxide
THPS & Bromine
THPS & Hydroperoxide
Biocides
* The Reference line 12 represents the av erage %
positive in a population where n= 3829
Legionnaires Disease Prevention
Legionella Risk Management



Identify all uses for and occurrences of water at a
facility and prepare process flow diagrams
Conduct a hazard analysis (i.e. Legionella)
Identify critical control points in the process to
eliminate or control the hazard and implement
the controls Cooling Towers – Drift eliminators
Theoretical implications – what is the
infectious particle?
Concentration of Legionella in Cooling
Tower Exhaust (Drift)?
•Tests show that most of the volume of drift is contained in ≤100 μ droplets
•Assume all drift were in 100 μ dia water spheres with the volume of each drop =
0.5 x 106 cubic μ, then each ml of drift would contain 2 x 106 droplets of water.
•In a typical CT there is a pound of air passing through the tower for each pound of
water. A 1000-ton CT will circulate 3000 gpm of water with Evapco’s counterflow
towers generate 0.03 gpm of drift (113 ml). This drift would be contained in
350,000 CFM of air.
Concentration of Legionella in
Cooling Tower Exhaust (Drift)?
•If there are 100 Legionella/ml, then each minute 11,3000 Legionella bacteria
are dispersed in 350,000 cu ft of air or about 1 Legionella per 30 cu ft or 850
liters
• Typical adult takes 12-20 breaths per min of 500 ml volume.
Thus, if one
inhaled only undiluted drift, an average person would inhale less than a single
Legionella per hour!
Explanation?
•For outbreaks to occur, Legionella must be dispersed as packets:
Poor drift eliminators leading to large droplets released (containing
multiple Legionella) evaporated to a small micron dia droplet
Explanation?
•For outbreaks to occur, Legionella must be dispersed as packets:
Poor drift eliminators leading to large droplets released (containing
multiple Legionella) evaporated to a small micron dia droplet
Pieces of biofilm break off (must be small to get in lungs)
Packets of packaged Legionella from protozoa
Legionella pellets expelled from the
ciliate Tetrahymena
Legionnaires Disease Prevention
Legionella Risk Management





Identify all uses for and occurrences of water at a
facility and prepare process flow diagrams
Conduct a hazard analysis (i.e. Legionella)
Identify critical control points in the process to
eliminate or control the hazard and implement the
controls
Describe the critical limits for the hazard
Establish a monitoring plan to validate the
control measures
Legionnaires Disease Prevention
Validation- Legionella Monitoring
What’s new in Legionella monitoring?



Total bacterial counts are not a substitute for Legionella
monitoring (except for perhaps in whirlpool spas).
Viable Legionella tests are still the accepted “Gold
Standard” for monitoring.
Tests based on nucleic acid (PCR) or antigen detection
are useful in emergency situations and positive tests
need to be confirmed with culture
Thank you
Questions?