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Aspirated freshwater in the lungs of an organ donor who died by drowning in a river was the likely source of Legionnaires disease in two patients who received lung transplants at a Philadelphia hospital last year.

While one recipient recovered after a course of doxycycline, the other experienced several postoperative complications and, after a clinical recovery, died 6 months after transplant from respiratory failure secondary to a mucous plug, reported Shannon McGinnis, PhD, of the Pennsylvania Department of Health, and colleagues in the .

"Although solid organ transplantation is known to increase the risk for infection with Legionella, likely due to required immunosuppressive therapy, transmission via the organs themselves has not previously been reported," they wrote.

Legionnaires disease is typically associated with water in man-made systems, although numerous Legionella species thrive in natural freshwater environments. The medical literature noted at least one case of associated with a near-drowning in lake water.

Although no specific testing for Legionella species was performed at the Philadelphia hospital, the results of routine water testing during this period were all unremarkable and there was no water disruption during this time. Furthermore, no other cases of Legionnaires disease were reported in the 6 months before or after these two cases.

"Epidemiologic, environmental, and laboratory evidence suggest that the source of infection was likely the transplanted lungs," McGinnis and colleagues concluded.

"The present findings suggest that clinicians caring for patients who receive organs from donors who experienced freshwater drowning also should maintain a higher index of suspicion for legionellosis, even in organ recipients without classic clinical symptoms," they wrote. "In such patients, posttransplant antimicrobials could be tailored to include agents that combat atypical waterborne organisms."

"Prompt assessment by astute clinicians can result in more rapid diagnosis and treatment of Legionnaires disease, which requires organism-specific testing, thereby increasing the likelihood of a full recovery," they added.

The first case was identified in a woman in her 70s who received a right lung transplant in May 2022. On postoperative day 9, her bloodwork showed an elevated white blood cell count and acute anemia, suggesting an active infection. On imaging, the donor lung showed dense consolidation in the middle lobe. Over the next week, this evolved into a cavitary lesion. In early June, she underwent a bronchoalveolar lavage that was positive by nucleic acid amplification for Legionella species other than Legionella pneumophila.

The patient received doxycycline and fully recovered. There was no further testing to identify the species or rule out the presence of multiple Legionella species.

The second case was identified in a man in his 60s who received a left lung transplant on the same day as the first patient. He experienced several immediate postoperative complications, requiring extracorporeal membrane oxygenation and renal replacement therapy. He began a course of doxycycline on postoperative day 15. Imaging on postoperative day 24 revealed ground glass-appearing opacities in the donor lung -- a nonspecific sign of possible infection.

After the first case was disclosed, the second patient had sputum testing that was positive for L. pneumophila by culture at a commercial laboratory.

He initially experienced a clinical recovery, although he had a prolonged hospital stay. He died about 6 months after transplant due to respiratory failure secondary to a mucous plug.

The donor was a man in his 30s who fell into a river and was submerged for more than 5 minutes. Despite resuscitation efforts, he experienced brain death. The organs were recovered within 7 days of the drowning. The donor was not tested for Legionnaires disease before donation occurred.

Other organs from this donor were transplanted on the same day as the lungs. The heart recipient experienced a number of postoperative complications, but none suggested Legionnaires disease and no testing occurred.

The liver recipient had few complications; a urinary antigen test result for Legionella species was negative. The kidney recipient also had few complications, with no evidence of infection and no Legionella testing.

However, specimens from the donor were not available for testing during the investigation. "Specimens relevant to testing for Legionella are not required to be collected or saved from organ donors," McGinnis and team noted.

The CDC, the Philadelphia Department of Health, and the Pennsylvania Department of Health all tried unsuccessfully to secure clinical isolates or specimens from both lung transplant recipients. "The specimens collected from the patients either did not result in isolates after testing or were discarded by the commercial testing laboratory before additional testing could be performed," the authors added.

Both health departments conducted retrospective and prospective active case finding and did not identify any other cases of Legionnaires disease in the region, including among other people who were exposed to the transplant hospital during this period.

When unexpected donor-derived infections occur, providers are required to report the case to the United Network for Organ Sharing or the Organ Procurement and Transplantation Network for investigation by the Disease Transmission Advisory Commission and to public health authorities.

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