nosocomial legionellosis detection and prevention

Nosocomial LegionellosisDetection and Prevention

Philip Kurpiel MT, MPHNew York State Department of Health

Regional Epidemiology Program

February 2006

What Is Legionella ?

• It is a gram-negative bacteria.

• 42 known species, and 70 serogroups.

• Enjoys warm water environments.

• Requires protozoa and other gram negative bacteria to proliferate.

• Requires special media in order to be cultured.

Legionella and Human Disease

• Initially discovered in 1976 after an outbreak in a Philadelphia hotel that hosted a July 4th American Legion celebration

221 attendees ill. 34 died Legionella bacteria discovered in lung tissue and cooling tower.

• Today: ~ 2,000 cases of Legionella pneumonia are reported in the United

States each yearAn estimated 8,000 – 18,000 are thought to occur .Estimated to cause 2-15% of community acquired pneumonias.

In New York State 200 – 300 cases have been reported yearly the past two years.

Legionellosis

DEFINITION

Legionellosis: an infection with Legionella.

• Two manifestations predominate:

1. Legionella Pneumonia (“Legionnaires’ Disease”).

2. Pontiac Fever .

Extra pulmonary and wound infections have been reported too but are very rare.

Pontiac Fever

Pontiac Fever Is a self limited illness due to Legionella exposure in immune competent host

So named after an outbreak in Pontiac Michigan 1968

It can occur in any individual. Symptoms begin a few hours to a few days after exposure. Symptoms include fever, malaise, myalgia, and headache. Illness is self limited, and lasts 2-5 days.

Diagnosis:• Primarily by serology and symptoms.• Pontiac Fever patients may not have detectable levels of urinary antigen.

Legionella Pneumonia

Legionella Pneumonia: Onset 2-10 days after exposure.►Symptoms include:

• Moderate to severe pneumonia with infiltrates.

• Fever

• Non- productive cough

• Hyponatremia (low sodium)

►Occurs primarily in immune compromised hosts.• Elderly, immune suppressed, chronically ill (COPD, diabetic).

– Immune suppression and hematological malignancy seem to be the highest risks.

►Mortality 5-20%

CDC Case Definitions

Legionellosis Case Definitions for CDC - NNDSS (Revised 1/1/2006)

Confirmed:

1) Culture of any Legionella organism from respiratory secretions, lung tissue, pleural fluid, or other sterile fluid

2) Detection of Legionella pneumophila serogroup 1 antigen by urinary antigen using valid reagents.

3) Seroconversion with fourfold or greater rise in specific serum antibody titer to Legionella pneumophila serogroup 1 using validated reagents.

CDC Case Definitions

Case Definitions for CDC - NNDSS (Revised 1/1/2006)

Suspect:

1) Seroconversion with fourfold or greater rise in antibody titer to specific species of Legionella other than Legionella pneumophila serogroup 1 using validated reagents.

2) Seroconversion with fourfold or greater rise in antibody titer to multiple Legionella species using pooled antigen and validated reagents.

3) Detection of specific Legionella antigen or staining if the organism in respiratory secretions, lung tissue, or pleural fluid by direct fluorescent antibody DFA staining, immunohistochemistry, or similar method using validated reagents.

4) Detection of Legionella species by validated nucleic assay.

Culture

Good Points

• Gold Standard – leaves no doubt for diagnosis.

• Recovery allows you to match for sources

Draw backs

• Requires special media: BCYE agar

• Requires time 5-7 days to grow.

• Infection intracellular, patients do not often produce sputum.

Urine Antigen

Good Points

• High sensitivity (80-90%) High specificity (~100%)

• Rapid – only takes a few hours

Draw backs

• Antigen can be shed for months after infection which can distort source and timing.

• Only detects L. pneumophila 1. (Although some assays can cross-reacts with serogroup 3).

• Some patients can’t produce urine (e.g. ESRD patients)

Legionella Serology

Good Points• Allows for retrospective studies

• Some IFAs detect IgM

• Most Kits detect L. pneumophila serogroups 1-6

Draw backs• Requires months to make a diagnosis.

• IFA has lower specificity

• Single positive titers can be meaningless!

• Won’t detect other than serogroups 1-6

PCR and DFA

• DFA: Low sensitivity and specificity.

Should only be used as additional evidence

• PCR: Not widely available.

Theoretically it could be clinically valuable.

Be careful if using for environmental testing

Treatment of Legionella

• Effective Agents: Macrolides Fluoroquinalones Tetracyclines

• Non-Effective Agents: Penicillins Cephalosporins Aminoglycosides

• Agents of Uncertain Efficacy: Trimethoprim sulfamethoxazol

Glycopeptides

Carbapenems

Sources of Legionella Infection

Any stagnant warm water can be a reservoir for Legionella.

Ideal breeding temperature is between 77oF and 115oF.

Historically, two main sources of published outbreaks have been:

1) Cooling Towers

2) Domestic Hot Water Systems.

Sources of Legionella Infection: Cooling Towers


Trouble with cooling towers:

► Require careful maintenance.

► Large volumes of water and high powered fans enable wide dispersal.

► The largest outbreaks of legionellosis on record have been due to contaminated cooling towers.


Trouble with Hot Water Systems: Showering, drinking, or anything creating an aerosol can be an

exposure source

Hot water “dead legs”, and water tanks can provide ideal refuge for breeding.

.

Sources of Legionella Infection: Hot Water Systems

Dead Leg

Legionella Problems in Healthcare Facilities

• Why?

– Compromised patients are easy targets for Legionella

– Old buildings, old water systems, modern medicine.

• Nosocomial Legionella in MARO 2003-2005:– 20 different Hospitals reported cases.

– 10 nursing homes reported cases.

Number of Facilities Reporting Nosocomial Legionella in New York State 2001-2005

YearLong Term

CareHospitals

2001 3 2

2002 2 7

2003 6 6

2004 7 5

2005 11 14

Total 29 34

Yearly Rates* of Reported Legionellosis Cases in New York State 1992-2004

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Rat

e

Year* Rates Per 100,000

Frequency of Legionellosis in New York State by Diagnosis Date Jan 2002 – May 2005

0

10

20

30

40

50

60

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M

2002 2003 2004 2005

NYSDOH Legionellosis Guidelines for Surveillance and Control in Acute Care Facilities

Released July 14, 2005

Calls for clinical and environmental measures to be taken to identify and prevent nosocomial Legionellosis

Key Principle: Your facility should have a multidisciplinary Legionella workgroup.

• Medicine, Nursing• Infection control• Engineering, Maintenance• Administration


Clinical Surveillance:

1) Identify the Risk Groups

– Highest Risk:

Patients with severe immune suppression.

End stage renal disease patients.

Hematological malignancy patients.

– Moderate Risk:

Diabetic patients

Chronic lung disease Patients

Non-hematological malignant cancer patients

HIV patients

Elderly

Cigarette smokers


Clinical Surveillance:

2) Testing

• Patients in moderate and high risk groups with facility acquired pneumonia should be tested for Legionella by culture and urine antigen.

• Acute care facilities receiving long term care facility patients with pneumonia should test them for Legionella by culture and urine antigen.

NYSDOH Legionellosis Guidelines for Surveillance and Control in Long Term Care

– Guidelines Coming Soon…

LTC Clinical Surveillance:

Testing

• LTC residents hospitalized with pneumonia should be tested for Legionella by culture and urine antigen.

• Consider testing patients with pneumonia if they do not respond to antibiotic therapy.


Infection Control

1) Respiratory Equipment

Rinse respiratory equipment with sterile water after it has been cleaned and disinfected

Use sterile water to fill nebulizer reservoirs.

Avoid room humidifier units.

If use cannot be avoided,

Fill only with sterile water.

Sterilize or use high level disinfection on the device daily


Infection Control

2) Protective environments: Hematopoietic stem cell transplant, and Solid organ transplant units.

If environmental samples are positive disinfect, remove aerators and restrict tap water use.


Environmental Maintenance

1) Domestic Hot Water:

a. Remove Dead legs from the system.

b. If no long-term controls exist:

Perform hot water system disinfections twice a year by:

– Heat and Flush or Hyperchlorination

c. Flush the system when it is open for repair/construction or subject to water pressure changes.



Heat and Flush:

a. Heat hot water >160 oF

b. Flush through ALL fixtures at this temperature for >= 5 minutes.

c. Flow should be about the width of a pencil.

Hyperchlorination:

a. Add chlorine to the hot water system.

b. Flush chlorine through all fixtures until it is >=2.0 ppm free chlorine, and pH is between 7.0 and 8.0

c. Keep fixture closed for 2-24 hours, then flush thoroughly.

Long Term Control Measures

1) Chlorine Injection

- Drawbacks: corrosive to pipes, dangerous chemicals

2) Chlorine Dioxide

- Drawbacks: takes time, treatment failures have been reported, dangerous chemicals, needs monitoring

3) Copper Silver Ionization System

- Drawbacks: Expensive, needs monitoring

4) Anti-scald Mixing Valves:

- Drawbacks: Valve failure?


Environmental Surveillance

2) Testing Domestic Hot Water?

Quarterly water cultures are recommended for hematopoietic stem cell units and organ transplant protective units.

Assess needs in other units


Environmental Surveillance

If you decide to culture other areas routinely:

Decide how you will react to positives before you test.

Plan your test sites carefully.

Use established culture methods.

Avoid PCR and DFA testing.



3) Cooling Tower Maintenance

Consult ASHRAE and CTI standards as well as manufacturer standards for tower maintenance.

Seek professional engineering guidance

Some Good Ideas

Have a designee who follows cooling tower maintenance records.

Monitor biocide levels and dip-slide levels weekly.

Dip Slide

You Have a Case of Nosocomial Legionellosis.. Now What?

Nosocomial Legionellosis defined:

A case of Legionellosis by CDC definition that is …

Definite:

Spent all days 2-10 of incubation period in a healthcare facility.

Possible:

Spent some of days 2-10 in a health care facility.


Review patient’s history in the facility and the locations where they stayed. Evaluate possible exposures.

Perform a 1 month retrospective surveillance of nosocomial pneumonia cases.

►Try to test past nosocomial cases by urine antigen if applicable.


• Conduct prospective surveillance for at least six months beyond the last case.

Acute Care Facilities:• Monitor frequency of Legionella testing of nosocomial

pneumonia patients who are in the moderate and high risk groups.

Long Term Care Facilities:• Assure that residents hospitalized with pneumonia get tested.

• Test returning residents by urine antigen if necessary.

You Have a Nosocomial Legionellosis.. Now What?

QUIZ TIME:• Should you culture your water system, and cooling tower?

1) If your case was culture positive? – Yes

• Culture your hot water system

• Culture your cooling tower if applicable

2) If your case was urine antigen positive?

May not be necessary for one case.

• If you detect another case in the surveillance period do water testing.


QUIZ TIME:

• Should you disinfect you hot water system?

- Yes, if you have no long term control and you have not disinfected in prior 6 months.

- No, If you have a long term control in place.

- Yes, if you have a case and positive water cultures.


QUIZ TIME:

• You have a case, and you have Legionella in your water. Should you restrict water use?

• Yes,

– IF… positives samples are found on organ or hematopoietic stem cell transplant unit, then restrict water use on that unit.

Water restrictions can be imposed to protect other immune compromised patients. The circumstances of the outbreak, and the risk level of the patients need to be considered.

Other Questions?

• There are other issues covered by CDC and NYSDOH Guidelines not covered in this slide set.

• Please consult these references.

– CDC MMWR, Guidelines for Environmental Infection Control in Health-Care Facilities. June 6, 2003

– CDC MMWR, Guidelines for Preventing Health-Care Associated Pneumonia. March 26, 2004

– New York State Department of Health Guidelines for Surveillance and Control of Legionellosis in Acute Care Facilities. July 14, 2005

The End

Thank You

nosocomial legionellosis detection and prevention

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