S3.1d High histoplasmosis incidence in kidney transplant recipients in Santa Fecity, Argentina
Authors: Effron Guillermo Garcia , Gaite Judith Ana , Gamarra Soledad , Nuñes-Piñeiro Verónica , Agusti Joaquín , Cassini Evelyn , Arriola Mariano , Paladini José Hugo , Gaite Luis , Viches Florencia 
Published: September 2022

Abstract

S3.1 Neglected implantation mycoses, September 21, 2022, 4:45 PM - 6:15 PM

Objectives
Histoplasmosis is endemic in the central/northeast region of Argentina. No data on the incidence of Histoplasmosis are available in most countries. It is estimated that the incidence of this mycosis is low in solid organ transplant recipients. In endemic areas of the USA (Ohio), the incidence of histoplasmosis in kidney transplant recipients is 0.25%. The objectives of this work are to describe the epidemiology, clinical forms, and evolution of kidney transplant recipients’ diagnoses with histoplasmosis in Santa Fe city, Argentina.

Methods
A retrospective study was carried out between July 2017 and July 2020 at the Nephrology, Urology, and Cardiovascular Diseases Clinic, Santa Fe (Argentina). Demographic, clinical, and laboratory data were obtained and analyzed. Histoplasmosis diagnosis was performed by means of histopathology (intracellular yeasts), recovery of Histoplasma spp. by culture, and/or positive nested PCR specific for Histoplasma Hc100 gene. No antigen detection method was available in Argentina at the time of the study.

Results
During the 36 months of the study, 225 kidney transplantations were performed. Out of these patients, 10 were diagnosed with histoplasmosis (4.44%). All the patients were Santa Fe province inhabitants. Patients’ median age was 47 years old and 90% were male. A total of 9 patients (90%) presented the disseminated form of the disease and 1 the pulmonary form; 8 were recipients of their first transplant and 2 were second transplant recipients. All received thymoglobuline induction as immunosuppressive therapy. In all, 4 were diagnosed with histoplasmosis in their first-year post-transplantation (mostly 6-12 months) and the rest after 1-year post-transplantation. At the time of the histoplasmosis diagnosis, five patients presented glomerular filtration between 30 and 60 ml/min, two &lt;15 ml/min, two between 30 and 15 ml/min, and only one with glomerular filtration &gt;90 ml/min. A total of 7 retained graft function at the end of treatment, 3 lost the graft (1 due to death). Histoplasmosis diagnosis was done in skin biopsies (n = 4), bone marrow (n = 3), CNS (n = 1), kidney graft (n = 1), and respiratory sample (n = 1). Laboratory diagnosis was done by histopathology, culture, and PCR in 3 cases (30%), by culture and PCR in 2 cases (20%) and by PCR alone in 5 cases (50%). Thus, all 10 patients showed positive nested PCR results. These results were informed within 24 h of receiving the samples. Cultures were positive in 5 cases and were considered positive on average after 26 days (ranging from 15 to 44 days) of incubation. All patients received amphotericin B as initial treatment. A total of 8 patients (80%) continued treatment with itraconazole and 1 with Voriconazole. Good response was observed in 9 patients.

Conclusion
We found a high incidence of histoplasmosis in kidney transplant recipients (10 times higher than reports from other endemic areas). Disseminated histoplasmosis was found in 90% of the patients. The same percentage of patients showed compromised graft function. The diagnosis was done after 1 year of transplantation in 60% of the cases. Diagnosis by histopathology/culture showed 50% sensitivity while nested PCR showed better sensitivity and diagnostic speed.