legionella matt zahn, md medical director epidemiology and assessment orange county health care...

LegionellaMatt Zahn, MD

Medical DirectorEpidemiology and Assessment

Orange County Health Care AgencyAugust 11, 2015

Bronx, New York Outbreak of Legionella

• Reported individuals with Legionnaires': 113

• Individuals treated and discharged: 76

• Individuals with Legionnaires' deceased: 12

• All deceased individuals were adults with underlying medical conditions

• No new deaths have been reported in the last six days.

• No new cases diagnosed since August 3.

New York City Messaging: Safety of Water Supply and Air Conditioning

•11 sites have tested positive within the community impact zone

•“Health officials remain confident that the source of the outbreak is from a location in the initial round of positive test sites, and that through disinfection of the source, the outbreak has been contained.”

•New York City’s drinking water supply and other water features, like fountains, shower heads and pools, are safe

•Water towers are unaffected by legionella •Home air conditioner units are unaffected

Legionella History

• 1976: First recognized after outbreak of pneumonia in attendees of American Legion convention in Philadelphia

• Pontiac fever

• Named for Pontiac, Michigan

• In 1968, several workers at the county's department of health came down with a fever and mild flu symptoms, but not pneumonia. After the 1976 Philadelphia event, the Michigan health department re-examined blood samples and identified Legionella as the pathogen

• 1980: First case of hospital-acquired Legionnaires’ Disease

Legionellosis Epidemiology

• Estimated 8000-18,000 cases/year in US (2000/year reported)

• Under-diagnosed

• Estimated 2-15% of community-acquired pneumonia

• Fatality 8% ( 5-30%)

www.cdc.gov/legionella; Legionellosis-United States, 2000—2009, MMWR, WeeklyAugust 19, 2011 / 60(32);1083-1086

Legionella in California

Legionella in California

Orange County Legionellosis

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Legionella species• Poorly staining gram-

negative bacilli

• Does not grow on routine culture media

• Over 40 species

• Legionella pneumophila serogroup 1 causes 80-90% of identified clinical infections

Legionella Disease Spectrum

• Pontiac Fever

• Pneumonia (Legionnaires’ Disease)

Pontiac Fever

• Self-limited influenza-like illness

• No lower respiratory tract involvement

• Incubation period 5-66 hrs

• Usually 24-48 hrs

• Attack rate: high ( 50-90%)

Legionnaires’ Disease

• Fever and lower respiratory tract disease

• Pneumonia

• LFT elevation common

• Incubation period 2-10 days

• Usually 5-6 days

• Mortality: 8% (5-30%)

• Attack rate: <5%

Legionnaires’ Disease Diagnosis

• Culture (requires special media)

• Urinary antigen

• Detects Legionella pneumophila serogroup 1

• Sensitivity: 60%--80%; specificity >99%

• Paired serologies

• DFA

• PCR

Legionellosis Treatment

• Quinolones or Macrolides

• Add Rifampin if severe disease

CDPH Legionella Case Definition

• Clinical symptoms compatible with Legionella

• AND

• Confirmatory Laboratory Test:

• Urinary Antigen OR

• Culture OR

• Validated positive PCR OR 

• DFA OR

• Serology—fourfold increase from baseline

Legionella Transmission

• Primary route: inhalation of an aerosol containing

• Some cases due to ingestion of contaminated water and subsequent aspiration or pharyngeal colonization

• Not transmitted from person-to-person

Host Risk factors

• Immune compromised, especially cellular immunity

• Age >50 years

• Smoker

• Chronic lung disease

• Diabetics

Exposure Risk Factors

• Travel: overnight stay outside of home

• Exposure to aerosols of potable water

• Recent plumbing repairs or maintenance work

• CDC categories:

• Travel-associated

• Healthcare-associated

• Community-acquired

Legionella in the Environment

• Commonly present in potable water

• Man-made freshwater environments

• Live in symbiosis with amoebae in the biofilm that lines water-containing pipes and tanks

• Thrives in stagnant warm water ~25-42C (77-108F)

Legionella Reservoirs

• Hot tubs/ whirlpool baths

• Cooling towers

• Hot water tanks

• Humidifiers

• Decorative fountains

• Survives in cold temperatures, including in ice

• Large plumbing system: dead legs/areas of stagnation

• Showers

• Cooling towers

• Whirlpools

• Misters

LADPH Surveillance Review

893 confirmed cases67 nosocomial

48 definite19 possible

48 single cases32 definite16 possible

19 cases: 8 outbreaks16 definite3 possible

D. Terashita, 2015

LADPH Surveillance Review

• 8% of all LAC legionellosis healthcare associated

• 28% of healthcare-associated cases are outbreak related

• 50% of subsequent healthcare-associated cases >2 months after index case

• 75% of environmental cultures + for Legionella

• When patient and environmental serotypes matched, cases clustered tightly in time

• When patient and environmental serotypes did not match or environmental cultures were negative, subsequent cases occur much later

D. Terashita, 2015

Transmission in Healthcare-Associated Legionellosis:

Hospital outbreaks attributed to inhalation from:

• Showers

• Faucets

• Respiratory therapy equipment

• Room-air humidifiers

• Cooling towers

• Medical center outbreak associated with decorative fountain in the lobby

Hospital outbreaks attributed to ingestion or aspiration of potable water and ice

CDC Case Definitions for Healthcare–Associated

Legionellosis• Definite healthcare-associated:

• Lab-confirmed and patient hospitalized (or residing in a healthcare facility) continuously for ≥10 days prior to symptom onset

• Possible healthcare-associated:

• Lab-confirmed and patient hospitalized (or residing in a healthcare facility) for a portion of the 2-9 days before onset of symptoms

Healthcare Associated Outbreak

CDC defines as:

• ≥2 healthcare‐associated case of same serotype

• 1 transplant associated case

Proposed CDC Best Practice in 2015:

• Environmental investigation should be initiated after one DEFINITE healthcare-associated case

After One Suspect or Confirmed HA Legionella Case, CDPH

Recommends:

• Provide Guidance to facility

• Review medical/microbiology records of past 6 months

• Initiate active surveillance for at least 2 months

• OCHCA recommends 3 months

Potential Immediate Control Measures - 2

• Restrict patient showering

• Restrict drinking from potable water sources (bottled water)

• No ice from the ice machine

• Turn off decorative water features and whirlpools and/or spas until cultures available/remediation completed

• Ensure use of sterile water in water-based devices that produce aerosols (e.g., respiratory therapy equipment, and humidifiers)

• Install point-of use filters for faucets and shower-heads if anticipate delay in assessment/remediation

Point of Use Filtration

• May be a useful approach in a strategic set of faucets

• Not practical solution for an entire hospital

• Must be changed frequently

Legionella Testing SitesPer CDC Recommendations

Examples include, but not limited to:• Showers• Water faucets• Cooling towers• Hot-water tanks• Carpet cleaner water tank

Routine Testing of Water in Healthcare Facilities?

• In 1992 study of 84 hospitals in Quebec:

• At least one sample was positive from 67% of facilities

• In a study of 11 healthcare facilities in Italy:

• 87% of water samples positive for Legionella species

• No increase in cases noted

• BUT

• Multiple studies have found that culture positive results from water sources in HCFs match facility cases

• Legionellosis is chronically underrecognizedAlary MA, JID, 1992Legnani, JID, 1992

Recommendations for Routine Testing of Hospital Water Supplies for Legionella

• CDC recommends culturing hospital water supplies for Legionella only in response to the identification of nosocomial infection

• Hospitals performing organ transplantation are recommended to routinely test water for Legionella

• Certain state and local health departments recommend a more proactive approach, with culture of the water system and active surveillance for cases if Legionella isolated

• VA hospital system recommends routine quarterly testing of facilities

• Allegheny local public health recommends environmental response if 30% or more environmental samples are positive

• Several other nations, including the Netherlands, Germany, France, Denmark, and Taiwan, now mandate routine environmental surveillance for Legionella in hospitals

CDC Recommendations for Water Maintenance

A. Maintain hot water temperature at the return at the highest temperature allowable by state regulations or codes, preferably > 124ºF (> 51ºC), and maintain cold water temperature at <68ºF (<20ºC)

B. If the hot water temperature can be maintained at > 124ºF (> 51ºC), explore engineering options (e.g., installing preset thermostatic valves in point-of-use fixtures) to help minimize the risk of scalding C. When state regulations or codes do not allow hot water temperatures above the range of 105ºF--120ºF (40.6ºC--49ºC) for hospitals or 95ºF--110ºF (35ºC--43.3ºC) for nursing care facilities or when buildings cannot be retrofitted for thermostatic mixing valves, follow either of these alternative preventive measures to minimize the growth of Legionella spp. in water systems:

1. Periodically increase the hot water temperature to > 150ºF (> 66ºC) at the point of use (153)2. Alternatively, chlorinate the water and then flush it through the system (153--155)

Conclusions• Legionella healthcare-associated disease is a

significant cause of morbidity and mortality

• Legionellosis is underrecognized

• Routine environmental testing for Legionella is of uncertain benefit

• Aggressive response to HA outbreaks is paramount

In other news….

Ebola

• Two cases reported in week leading to August 2:

• One in Sierra Leone

• One in Guinea

• OCHCA continues to follow travelers from all three impacted countries

MERS-CoV in the Republic of Korea

• 186 total cases associated with that country’s outbreak

• Last confirmed case had illness onset of July 4

• MERS-CoV should be considered in those with lower respiratory tract disease and:

• Traveler from Korea and healthcare facility exposure

• Travel from the Arabian peninsula

Orange County with First Confirmed West Nile Case of Season Last Week