What You Need To Know
Key Points or Updates: :
- Legionnaires’ disease cases rise during warmer months and typically peak in summer or early fall.
- Consider Legionella in all patients presenting with pneumonia, whether community-acquired or healthcare-associated.
- Collect both a urine specimen for Legionella urinary antigen testing (UAT) and a lower respiratory specimen for Legionella culture or PCR testing concurrently.
- The Legionella UAT only detects Legionella pneumophila serogroup 1.
- Other species/serogroups may be missed unless a lower respiratory specimen is tested by culture or PCR.
- If a patient tests positive on the Legionella UAT, please send a lower respiratory specimen to NJDOH’s Public Health Environmental Laboratories (PHEL) for further testing.
- Please distribute to all clinical staff in Internal Medicine, Geriatrics, Primary Care, Infectious Diseases, Emergency Medicine, Family Medicine, Laboratory Medicine, and Infection Control.
INFORMATION FOR HEALTHCARE PROVIDERS, FACILITIES, AND CLINICAL LABORATORIES
Healthcare providers should consider Legionnaires’ disease in patients with pneumonia. The urinary antigen test (UAT) is a rapid, widely available diagnostic that detects Legionella pneumophila serogroup 1 (Lp1); however, a negative result does not rule out infection with other Legionella species or serogroups.
To improve diagnostic yield, consider ordering a UAT in conjunction with Legionella culture and/or PCR testing of a lower respiratory specimen (e.g., sputum, tracheal aspirate, or BAL fluid). These methods enable detection of non-Lp1 Legionella species. If in-house culture or PCR testing is unavailable, use a reference laboratory.
For patients with a positive UAT result, request that the clinical laboratory forward a lower respiratory specimen to NJDOH’s Public Health and Environmental Laboratory (PHEL) for additional public health surveillance testing. Shipping guidance is available, and testing is provided at no cost.
Culture
Advantages:
- Detects Legionella species and serogroups beyond Lp1
- Provides bacterial isolates for molecular typing to support outbreak investigations (allows for public health to compare clinical and environmental isolates)
- UAT alone does not allow for molecular comparison
Limitations:
- Longer turnaround time
- Requires specialized media and technical expertise
- Reduced sensitivity if collected after antibiotic initiation
PCR Testing
- Complements culture for broader detection, including non-Lp1 species
- Faster turnaround time
- Not dependent on viable organisms, so less affected by prior antibiotic use
Reporting
Healthcare providers and administrators are required to report cases of legionellosis (Legionnaires’ disease and Pontiac fever) to the local health department where the patient resides within 24 hours of diagnosis (N.J.A.C. 8:57 – 1.4). If the patient’s residence is unknown, report to your own local health department. Contact information is available at: localhealth.nj.gov. Timely identification and reporting of cases of legionellosis is important, as this allows public health officials to quickly identify and stop potential clusters and outbreaks by linking new cases to previously reported ones.
Contact Information:
Water Systems and Environmental Infection Control Unit
Infection Control, Healthcare, & Environmental Epidemiology Program
Communicable Disease Service
New Jersey Department of Health
ICHEE.Water@doh.nj.gov