Use of gastrointestinal syndromic multiplex molecular assays and detection of <i>Escherichia coli</i> pathotypes in pediatric wards

<i>Escherichia coli</i> pathotypes are enteric pathogens detected in gastrointestinal multiplex polymerase chain reaction (mPCR), with controversial clinical relevance. Our study aimed to describe clinical features and therapeutic decisions associated with <i>E. coli</i> detections in gastrointestinal mPCR. Children with positive mPCR for enteroaggregative (EAEC)<i>,</i> enteropathogenic (EPEC)<i>,</i> enterotoxigenic (ETEC), Shiga toxin-producing <i>E. coli</i> (STEC), and enteroinvasive <i>E. coli</i> (EIEC)/<i>Shigella</i> identified in two pediatric hospitals over 18 months (2020-2021) were included. We described the frequency of <i>E. coli</i> detection and subsequent modifications in antibiotic strategies. Among the 2,471 mPCRs performed, 338 (14%) tested positive for at least one <i>E. coli</i> pathotype. The patient's mean age was 4.2 years, with 95% experiencing gastrointestinal symptoms. Clinical presentation was generally comparable between <i>E. coli</i> pathotypes. A recent travel abroad was reported in 68/338 (20%) cases and was mainly observed in EIEC/<i>Shigella</i> infections. An <i>E. coli</i> was detected alone in 177/338 (52%) cases and with another virus, bacteria, or parasite in 161 (48%) cases. Multiple enteric pathogens were mainly detected with ETEC (<i>n</i> = 24/26, 92%) and EAEC (<i>n</i> = 82/121, 68%) detections. Antibiotic therapy was prescribed in 136/338 (40%) cases, with initiation based on mPCR results in 69/338 (20%). No antibiotic therapy was discontinued following positive mPCR results. Among the 69 initiations, 31 were deemed inappropriate after retrospective chart review. <i>E. coli</i> detection with mPCR tests may lead to inappropriate antibiotic initiation. Caution is advised when interpreting results from gastrointestinal mPCRs in children, as clinicians may be unaware of their often unclear or irrelevant clinical significance.IMPORTANCE<i>Escherichia coli</i> pathotypes are increasingly detected through the widely used syndromic gastrointestinal multiplex PCR panels. However, their clinical significance and impact on antibiotic therapy in children remain uncertain. This study describes the clinical and microbiological characteristics associated with <i>E. coli</i> detections, as well as the subsequent modifications in antibiotic strategies. It highlights the frequent detection of <i>E. coli</i> pathotypes, often in association with other enteric pathogens, and reveals that nearly half of the antibiotics prescribed following these results were deemed inappropriate. These results underscore the need to enhance clinicians' interpretation of <i>E. coli</i>-positive results and reassess treatment strategies to optimize patient care.