Multiplex Polymerase Chain Reaction (PCR) Diagnosis of Diarrhea in Kidney Transplant Patients: Etiological Spectrum and Association with Acute Graft Dysfunction

Background: Diarrhea is a frequent complication after renal transplantation, potentially leading to poor health, graft injury, or even rejection. Causes include infections (e.g., Campylobacter, E. coli, Salmonella, C. difficile, Giardia, Norovirus, Rotavirus) and immunosuppressive medications. This study aimed to determine the etiological spectrum of diarrhea in renal transplant recipients using stool multiplex PCR and evaluate the impact of diarrheal episodes on graft function. Methods: This single-center prospective study included renal transplant recipients admitted with diarrhea from April 2022 to January 2024, whose stool underwent multiplex PCR testing. Serum CMV RT-PCR and colonoscopy were performed when clinically indicated. Renal function was tracked using serum creatinine during the diarrheal episode and one month after recovery. Results: Of 100 renal transplant recipients recruited, stool multiplex PCR identified pathogens in 90%. Norovirus was the most frequent isolate, followed by Giardia lamblia. Enteroaggregative E. coli (EAEC) was the most common bacterial cause, and Norovirus/EAEC co-infection was prevalent. (Figure 1) CMV viremia occurred in 11%, and CMV colitis was diagnosed by biopsy in two individuals. Mycophenolate mofetil (MMF) was implicated as the cause of diarrhea in 4%. Significantly, acute graft dysfunction occurred in 70% of patients during their diarrheal episode. Conclusion: Diarrhea in renal transplant recipients is strongly associated with acute graft dysfunction. Stool multiplex PCR offers a high diagnostic yield, enabling prompt etiological identification. This study facilitates targeted treatment, optimization of antimicrobial use, and helps avoid unnecessary immunosuppression adjustments, and may ultimately improve graft outcomes. Funding: Clinical Revenue SupportFigure 1. Commonly isolated pathogens on the FilmArray GI panel test in renal transplant recipients with diarrhea