Infectious Diarrhea in Kidney Transplant Recipients

Introduction Infectious diarrhea represents a significant and frequent complication among kidney transplant recipients, primarily due to the immunosuppressive therapy required to prevent graft rejection. This condition poses substantial risks to both graft function and patient survival, driven by increased susceptibility to opportunistic pathogens and potential medication-related gastrointestinal effects. This study aims to characterize the pathogen spectrum and associated risk factors of infectious diarrhea in a German cohort of kidney transplant recipients, providing insights into regional patterns and clinical implications. Methods A retrospective cohort study was conducted, analyzing 604 patients, including 436 kidney transplant recipients, who were hospitalized with infectious diarrhea (ICD-10 codes A00-A09) at the Universitätsklinikum Düsseldorf (UKD) between January 2019 and December 2023. Nontransplant patients (n = 168) were included as a comparison group to evaluate pathogen distribution and infection risk specific to immunosuppressive therapy in transplant recipients. Pathogen identification was performed focusing on stool samples. Data collected included transplantation status, dates of admission and transplantation, recurrence rates, and detailed immunosuppressive regimens. Statistical analyses were applied to evaluate pathogen distribution, temporal patterns, and the influence of immunosuppression on infection risk. Results The most prevalent pathogens identified among kidney transplant recipients were <i>Clostridioides difficile</i> (26.3%), cytomegalovirus (CMV, 12.3%), enteropathogenic <i>Escherichia coli</i> (EPEC, 8.6%), and norovirus (4.8%). Immunosuppression significantly heightened infection susceptibility, with <i>Clostridioides difficile</i> infections occurring notably more frequently and CMV-related diarrhea observed exclusively in the transplant cohort. Recurrence rates were elevated for both CMV and <i>Clostridioides difficile</i>, underscoring their clinical persistence. Temporal analysis revealed a median onset of CMV infections at approximately 13 months post-transplantation, with no significant seasonal variation. Conclusions The predominance of opportunistic pathogens such as <i>Clostridioides difficile</i> and CMV in kidney transplant recipients reflects the profound impact of immunosuppression on infection risk and pathogen profiles. These findings emphasize the necessity for enhanced diagnostic approaches in kidney transplant recipients, including early and comprehensive pathogen screening, and targeted prevention strategies, such as optimized and maybe prolonged CMV prophylaxis and stringent hygiene protocols for <i>Clostridioides difficile</i>. It emphasizes close monitoring of a potential viral load in blood samples, especially after cessation of the routine CMV prophylaxis after kidney transplantation. This study contributes to a better understanding of infectious diarrhea in this vulnerable population and lays the groundwork for improved clinical management, overall cost reduction, and future prospective research.