A Unique Case of Heart Transplant and Toxoplasma gondii Infection in a Parasite-Seronegative Recipient: A Case Report

INTRODUCTION: The protozoan Toxoplasma (T.) gondii is responsible for toxoplasmosis, and this parasitosis represents a high risk in solid organ transplant procedures. In heart transplant patients, T. gondii infection is usually fatal since immunosuppressive drug therapy is administered to recipients. CASE PRESENTATION: A 62-year-old woman with severe biventricular dysfunction and seronegative for T. gondii underwent a cardiac transplantation from a donor seropositive for anti-T. gondii IgG antibody. The recipient exhibited post-transplant complications, including acute renal failure and difficulty in weaning from mechanical ventilation, ultimately requiring tracheotomy. The recipient underwent immunosuppressive pharmacological prophylaxis to prevent organ rejection. From a virological point of view, the recipient was monitored, and analyses performed on blood and serum revealed the presence of T. gondii DNA on blood. In addition, other viral and bacterial infections were observed. Afterward, molecular and anatomopathological investigations on cardiac biopsies were performed, and neither test revealed the presence of T. gondii DNA. CONCLUSION: On the one hand, prompt infection management and continuous monitoring are crucial to control viral and bacterial loads and, on the other hand, to optimise antimicrobial treatment, thus ensuring the gradual clinical stabilisation of the patient. Finally, it is important to highlight the need to review diagnostic screening protocols for organ donors to detect potential reactivation of microorganisms, viruses, and parasites that could be a fatal risk to recipients.