P1737microbiological Diagnosis of Diarrhea in Renal Transplant Patient by Multiplex PCR

Abstract

Background and Aims Acute gastroenteritis is an unwelcome and harmful yet unavoidable complication in the renal transplant patient. Infections, especially atypical organisms like Norovirus, Cryptosporidium, along with typical microorganisms like E. coli and Giardia, form the significant players in the pathogenesis of diarrhea. Standard methods of staining and culture have reduced sensitivity as well as require considerable time for the reports. Stool Polymerase Chain Reaction (PCR)is a quick, sensitive, and hassle-free method that diagnoses more than 20 organisms within 1 hour. This study aims to determine the infective etiology of acute gastroenteritis in the transplant population as well to compare the yield of stool PCR with conservative methods. Method We retrospectively analyzed all renal transplant patients admitted between 2015 to 2018 with complaints of diarrhea (>3 stools/day with loose consistency). The sample was tested for conventional microbiological methods, including a stool routine for microscopy and culture. A stool sample was also sent for Multiplex PCR, which was analyzed by Bio Fire FilmArray GI Panel, which identifies 22 enteropathogens. Endoscopic procedures were also undertaken in suspected cases for CMV colitis and pseudomembranous colitis. Results 110 diarrheal events (admission for diarrhea) were recorded in 82 patients, with 181 organisms isolated in all samples. 16 events did not reveal any organisms in stool PCR. 85% sample yielded a positive result. The conventional method yielded a positive result in only 32.3% as compared to stool PCR. Co-infections were common, as 71.2% of events were associated with 2 or more organisms. Conventional methods failed to diagnose any co-infections. Norovirus G1/G2(20%) was the most common organism isolated from the stool, followed by Giardia (17%) and Enteropathogenic E. coli (16%). Giardia Lamblia with Norovirus G1/G2 was the most common co-infection in 19% of patients. Conclusion Stool PCR significantly improves the diagnostic yield in diagnosing enteric pathogens. Stool PCR is especially sensitive in detecting multiple organisms where conventional microbiological methods were completely unsuccessful. Norovirus is the most common enteropathogen, which is not picked by the conventional method. Giardia with Norovirus was the most common co-infection among post-transplant patients.