Lab Matters Spring 2019 - Page 27

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. Spring 2019 LAB MATTERS 25