Innovative Methods to Control, Investigate, and Monitor for

Legionella: A Panel Discussion

• Introduction—Mark Bergtholdt• Water Management Plans—

Brooke Winter• Investigation as a way of

preventing—Mark Bergtholdt• Using a Rapid Bacteria

Screening Method to Assess Legionella Risk—Lisa Rogers

Introduction: What is Legionella and why is it important

Mark Bergtholdt

Discovered in 1976 at an

American Legion Convention

in Philadelphia

Attendees becameill with pneumonia

221

Total Cases

2/3 Hospitalized

34Deaths

Bacteria Legionella pneumophila

were found to be the cause

Legionella:What it is and where does it come from?

Organism CharacterizationLegionella is a bacteria

43 or more identified species of Legionella

Multiple Serogroups, with over 60 serogroups presently identified for the

genus

Legionella Pneu-mophila, Serogroup 1Other L. pneu-mophila serogroups

70%20-30%

5-10%

Grow best at 68 to 115o Fahrenheit(Water supply systems often kept at 77 to

108oF)

Can be found in natural surface waters and in buildings

Infect/replicate in both protozoa and human white blood cells

The protozoa/blood cells infected with Legionella burst and release the bacteria into

the water

Ecology of Legionella

35-46˚C (95-115˚F)

Legionella’s optimalgrowth

temperature

<20˚C (68˚F)Predominantly dormant,

but still viable

60˚C (140˚F)90% Kill in 2

Minutes

Legionella fuses with the amoeba inside a membrane-bound

vacuole and replicates

Legionella releases from the amoeba,

exiting as the amoeba dies

Legionella enters the amoeba

Legionella attaches to biofilm

Replication occurs

Legionella reaches maturation

Some Legionella form new colonies

Others continue to end fixture

Legionella are found in the biofilms thataccumulate in the built environment:

How Legionella causes

human infections

The bacteria travel downstream to locationswhere it is aerosolized, such as:

Susceptible Individual:

Susceptible Individual:50+ years of age

Susceptible Individual:50+ years of ageHas Chronic Lung Disease

Susceptible Individual:• 50+ years of age• Has Chronic Lung Disease• Is a current or former smoker

Susceptible Individual:50+ years of ageHas Chronic Lung DiseaseIs a current or former smokerIs immunocompromised

How does a bacteria that enters an amoeba infect Humans?

The Legionella replicates inside the white blood cellLegionella releases from the white blood cell, exiting as the cell dies.

Legionella is engulfed by the white blood cell

Legionella go on to infect other white blood cells in the lung causing a pneumonia like illness

Incubation Period2 day -14 day

High feverHeadacheChills

Muscle pain

Dry CoughDifficulty breathing

Symptoms are severe; the individual will usually visit a physician

Legionnaires’ disease may be diagnosed as common pneumonia

Sputum culture orurine antigen testis used for positive identification

18,0008,000

Hospitalizations

Annually

to

4,000

Deaths Annually

Legionnaires’ disease is under reported

Legionnaires’ disease is under reported• Patients sometimes recover without medical assistance

Legionnaires’ disease is under reported• Patients sometimes recover without medical assistance

• Patients are not tested for Legionellosis by the physician

Legionnaires’ disease is under reported• Patients sometimes recover without medical assistance

• Patients are not tested for Legionellosis by the physician

• Patients are misdiagnosed

Reporting of Legionellosis

In Summary

• Legionella is a bacteria that needs a host to replicate.

• It is found in water and replicates in warm water

• It infects humans when the water containing the bacteria is aerosolized and inhaled by the person.

• It is an under reported disease