INFECTIOUS DISEASES
about developing a water management
program. “I think public health labs need
to educate the health care community,”
she said. “The first thing they should do
is not test, but to focus their efforts on
developing and implementing that water
management plan.”
Even public health labs that aren’t
involved in routine environmental testing
can play a key role in helping facilities
know what questions to ask and in
connecting them with resources to find
the expertise they need.
But when suspected or reported cases
emerge, it’s important to know whose
role it is to conduct and interpret
environmental tests as part of an
investigation, Levinson said.
Of course, such methods rely on
having clinical isolates to analyze—and
unfortunately, that remains a challenge,
Hughes said. Hospitals often use rapid
urinary antigen tests to diagnose Legionella
infections and determine a course of
treatment for the patient. Far fewer clinics
routinely collect or culture respiratory
samples. We’re “continuing to educate
hospital facilities about how important
it is that we receive isolates, especially
during cluster investigations,” Hughes
said.
The Hampton investigation has led the
New Hampshire team to reexamine its
approach. “Prior to the outbreak, we
offered clinical testing,” Levinson said.
“But a huge component of Legionella
investigations is the environmental
sampling, and a lot of states, including
us, are considering expanding our testing
capabilities to include both clinical
and environmental testing.” They’re
also thinking about moving beyond
culture and antibody-based methods to
add molecular methodology and DNA
sequencing.
Connecting the Dots
More advanced testing capabilities
have been key in New York City, said
Scott Hughes, associate director of the
NYC Department of Health and Mental
Hygiene. During a large outbreak in the
Bronx in 2015, the NYC lab worked with
the state’s Wadsworth Center and CDC
to implement improved methodology,
including polymerase chain reaction (PCR)
to screen environmental samples for
Legionella DNA. That allowed the response
team to quickly triage samples and reduce
the need for slow and finicky bacterial
cultures.
PublicHealthLabs
@APHL
They also used pulsed-field gel
electrophoresis and whole-genome
sequencing to compare strains from
environmental and clinical samples,
much like is often done in foodborne
illness outbreaks. “We’re really doing the
same thing, linking Legionella patients to
the environmental source,” Hughes said.
In that way, they were able to identify
the specific cooling tower responsible
for the outbreak and begin remediation
efforts. They’ve continued to use
these approaches with good results in
subsequent outbreaks.
Another challenge is being prepared for
more frequent outbreaks, he added. Given
the complexity of working with Legionella,
he recommends having testing expertise
in place before you need it. “In 2015 we
were unprepared for a large outbreak,”
he said. Now, “the agency as a whole is
looking much more closely for potential
outbreaks and clusters.”
The Value of Collaboration
For some labs, that preparation may
mean developing in-house testing
expertise, such as certification through
the Environmental Legionella Isolation
Techniques Evaluation (ELITE) program.
For others, it may involve strategic
partnerships.
Hughes agreed that region-specific
collaborations are crucial in both
surveillance and response efforts. Since
New York City and State passed laws in
2015 mandating regular cooling tower
checks, for example, the NYC lab works
closely with the Bureau of Water and
Sewer Operations.
Those partnerships are built on strong
lines of communication among a range of
health and environmental stakeholders
at local, regional and national levels. They
can also include non-traditional public
health partners such as city officials,
utilities and emergency responders, all of
whom Levinson found invaluable during
the Hampton outbreak.
Public health labs sit at the nexus of all of
these moving parts. “The most critical role
of the PHL is helping guide and provide
explanations of how to interpret the
laboratory tests,” said Levinson. “What
they can—and can’t—tell you is really
critical to how you communicate risk to
the public.”
Part of that includes understanding the
baseline local ecology of the organism
well enough to be able to identify changes
that might signal an outbreak. In one
ambitious project, Hall and the Iowa lab
are sequencing years of archived Legionella
samples to learn more about strain
variation and trends over time.
As people live longer and water
infrastructure ages, climates shift and test
methods evolve, outbreak investigations
are likely to become even more complex,
Levinson said. “Everyone has to come
together with their representative
expertise from the environmental site,
the epidemiology side, as well as the
laboratory side, to be able to put the
pieces together and make decisions that
ultimately protect the public’s health.” n
Levinson suggests a regional approach
to decision-making. “We’re learning not
every state has to reinvent the wheel and
offer everything themselves,” she said.
Instead, they are evaluating their needs
and resources and talking to neighboring
states to balance local and regional
capabilities.
APHL.org
Spring 2019 LAB MATTERS
25