# Infectious Diarrhea in Kidney Transplant Recipients

## TL;DR

This study examines infectious diarrhea in kidney transplant patients, identifying common pathogens and the impact of immunosuppression.

## Contribution

The study characterizes the specific pathogen spectrum and risk factors for infectious diarrhea in a German kidney transplant cohort.

## Key findings

- Clostridioides difficile was the most common pathogen (26.3%) in kidney transplant recipients.
- CMV-related diarrhea occurred exclusively in transplant patients and recurred frequently.
- Immunosuppression significantly increased susceptibility to infections like C. difficile and CMV.

## Abstract

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 Clostridioides difficile (26.3%), cytomegalovirus (CMV, 12.3%), enteropathogenic Escherichia coli (EPEC, 8.6%), and norovirus (4.8%). Immunosuppression significantly heightened infection susceptibility, with Clostridioides difficile infections occurring notably more frequently and CMV-related diarrhea observed exclusively in the transplant cohort. Recurrence rates were elevated for both CMV and Clostridioides difficile, 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 Clostridioides difficile 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 Clostridioides difficile. 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.