Organ Transplantation-related Tularemia
Amesh A. Adalja, MD, FACP, FACEP, FIDSA | September 12, 2019
The category A biothreat agent Francisella tularensis, the agent of tularemia, is endemic in many parts of the United States, and more than 100 cases occur annually. Tularemia has a variety of different forms and can be transmitted via various routes, including ingestion, inhalation, tick bites, and deer fly bites. A new report from the Centers for Disease Control and Prevention (CDC), published in Emerging Infectious Diseases, details 3 tularemia cases who acquired infection via organ transplantation.
Septic Shock in Recipients
A heart and 2 kidneys originating from the same donor were transplanted into 3 individuals in July 2017. All recipients subsequently developed septic shock and, in 2 recipients, blood cultures revealed F.tularensis. In 1 kidney recipient, the syndrome began 4 days post-transplant, progressed to disseminated intravascular coagulation (DIC), and ended in death. Blood cultures subsequently turned positive 3 days after death.
The second kidney transplant recipient had a similarly severe course, but providers were notified of the diagnosis of the first patient, and the patient was subsequently placed on doxycycline and ultimately survived.
The heart transplant patient became ill just hours post-transplant and recovered, but this patient had, interestingly, been on ciprofloxacin – a drug known to be effective in the treatment and prophylaxis of tularemia – just prior to transplant for a cardiac device infection. This patient also received an additional course of ciprofloxacin post-illness once tularemia was identified in the other patients.
Donor Risks
Nelson et al conducted an extensive investigation to ascertain the source of infection. The donor had been hospitalized with pneumonia (presumed to be aspiration), and the hospital course was complicated by thrombocytopenia and gastrointestinal bleeding requiring multiple blood product transfusions. No antemortem diagnosis of tularemia was made, and transplant donor screening was passed. Frozen spleen samples were found to be positive for F.tularensis during the investigation. There was no history of tularemia or exposures noted even after inspection of the donor’s residence, drinking water, and food sources. None of the blood donors for the transfusions received were found to be sources. The patient did reside on tribal lands in the southwest United States, and tribal populations are overrepresented among tularemia cases.
High Index of Suspicion
These cases illustrate that tularemia can be fulminant, especially in the immunocompromised. Though tularemia is susceptible to several different antibiotics, none of them is used routinely for perioperative coverage or for the treatment of pneumonia. The index of suspicion for tularemia must be very high, especially in individuals who do not have traditional risk factors, and routine cultures may not be revealing. These cases also illustrate that organs from those who die of febrile or unexplained infectious syndromes carry a higher risk for donor-derived infection and underscore the need for more aggressive pursuit of specific infectious disease diagnosis, especially in those who are critically ill.
Reference
Nelson CA, Murua C, Jones JM, et al. Francisella tularensis transmission by solid organ transplantation, 2017. Emerg Infect Dis 2019;25(4):767-775. doi:10.3201/eid2504.181807.
