84 A Randomized Control Trial of a Multiplex Gastrointestinal PCR Panel versus Usual Testing to Assess Use of Antibiotics for Patients With Infectious Diarrhea in the Emergency Department

Abstract

Infectious diarrhea is a common complaint in US emergency departments (EDs). While the most common causes of infectious diarrhea are viral, the most serious are usually due to bacterial or protozoal sources. In the ED, the provider has limited ability to evaluate for these more serious causes using traditional testing such as stool culture due to its low sensitivity and long processing time. Despite the fact that many cases of infectious diarrhea are self-limited, appropriate antibiotic therapy for most bacterial and protozoal causes of infectious diarrhea has been shown to lead to a shorter duration of symptoms and decreased spread of disease in close contacts. Multiplex gastrointestinal polymerase chain reaction (GI-PCR) panels test the stool for multiple microbiological sources and the results are available in about an hour. These tests allow the ED provider to start targeted treatment of diarrhea during the same visit thus avoiding the conundrum of empiric therapy. The objective of this study was to compare the use of a multiplex GI-PCR test to usual testing (ie, standard testing or no testing) in ED patients with suspected acute infectious diarrhea to determine if there is a change in appropriate antibiotic management. A prospective single center randomized control trial was designed to investigate antibiotic use in ED patients with moderate to severe suspected infectious diarrhea, comparing those that received GI-PCR to those that received usual testing. ED patients with signs of dehydration, inflammation or persistent symptoms were randomized to one of two treatment arms: (1) an experimental arm consisting of the multiplex GI-PCR (GIP) versus (2) a control arm which included usual testing or no testing. Mann-Whitney U test was used to compare the group differences for the continuous variables. A chi-square test or Fisher’s exact test was performed to test the group differences for categorical variables. For the purposes of our primary outcome, antibiotic usage, Farrington & Mannington score was used to calculate the confidence interval for the proportion difference between the experimental and control groups, and for each individual arm’s exact clopper-pearson confidence intervals was calculated. A total of 74 patients provided diarrheal stool samples and were randomized to either the experimental GIP arm or to the control arm consisting of usual testing. The treatment groups were well balanced with respect to characteristics at baseline. Participants in the GIP arm received antibiotics in 87% of bacterial or protozoal diarrheal infections (13/15) while those in the control arm received antibiotics in 46% of bacterial or protozoal infections (6/13) (p-value 0.042). The two-proportion difference was 0.41 with 95% CI of 00.07 and 0.68. ED use of multiplex PCR leads to an increase in antibiotic use for bacterial and protozoal causes of infectious diarrhea compared to usual testing. This increase in antibiotics appears to be appropriate given patients’ moderate to severe symptoms and a definitive identification of a likely bacterial or protozoal cause of symptoms. Results should be interpreted with caution due to the risk of side effects and antibiotic resistance associated with increased antibiotic use.