175 Healthcare: Biological Hazards

Medical Awareness of Physicians and Healthcare Workers

Healthcare workers need to be aware that the bacteria can be present in water systems and promptly test vulnerable and/or symptomatic patients and use appropriate antibiotics quickly.

As mentioned earlier, Legionnaires' disease most frequently attacks individuals who have an underlying illness or weakened immune system. The most susceptible include persons who are elderly, smokers, and individuals with suppressed immune systems.

Healthcare-Associated Outbreaks

How health department investigators respond to healthcare-associated cases and outbreaks of Legionnaires' disease depends on the type and size of the healthcare facility, existing capacity of the facility and health department, and the number of cases. Public health officials should work closely with healthcare facility staff at each step in the process. The appropriate healthcare facility points of contact (e.g., administrator, infection preventionist, clinician, quality assurance representative, facility manager or engineer) may vary, depending upon the step.

Deciding Whom to Test for Legionnaires' Disease

In healthcare settings, public health officials and healthcare providers should consider Legionnaires' disease as a possible diagnosis in any patient at risk for Legionnaires' disease with healthcare-associated pneumonia (pneumonia with onset =48 hours after admission). This is especially important among patients with severe pneumonia (e.g., those requiring intensive care) or if you identify any of the following in a healthcare facility:

• other patients with healthcare-associated Legionnaires' disease diagnosed in the past 12 months
• positive environmental tests for legionella in the past 2 months
• current changes in water quality that may lead to Legionella growth (e.g., low residual disinfectant levels, temperatures permissive to Legionella growth, nearby construction, areas of stagnation)

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