Impact of Rapid Molecular Multiplex Gastrointestinal Pathogen Testing in Management of Children during a Shigella Outbreak

Abstract

Fecal culture for isolation and identification of Shigella may take days. The BioFire FilmArray Gastrointestinal (GI) panel (bioMérieux, France) is a PCR-based assay that detects enteric pathogens including Shigella/enteroinvasive Escherichia coli (EIEC) in about an hour. The aim of this study was to evaluate the impact of GI panel detection of Shigella in a pediatric emergency department (ED) during an outbreak. Stool samples from children with acute gastroenteritis were tested by the GI panel. Test results were either withheld in preintervention (PRE) or reported to clinicians/families in the postintervention (POST) period. The impact of the GI panel testing on patient management and outcomes was measured. Shigella/EIEC was identified by the GI panel in the PRE (n = 30) and POST (n = 21) phase. The GI panel detected more Shigella infections than did culture; six of 31 (19.4%) Shigella GI panel-positive patients who also had stool cultures were missed by culture. Azithromycin therapy was prescribed for 20% of subjects in the PRE phase and 71.4% of subjects in the POST phase (P < 0.001). Time from the clinical encounter until starting azithromycin therapy was shorter in the POST phase (n = 9), 8.25 h (range, 6.37 to 52.37 h), than in the PRE phase (n = 1), 72 h. Six subjects in the PRE phase visited additional providers compared with one in the POST phase. Prompt diagnosis of shigellosis with the GI panel may provide the opportunity for prompt antimicrobial therapy and avoid additional visits to providers due to early definitive diagnosis. Prompt diagnosis of Shigella at an ED visit may optimize patient management and reduce transmission.

Keywords: BioFire GI panel; GI panel; IMPACT study; Shigella detection; outbreak management; shigellosis.

FIG 1

Shigella outbreak, Kansas City, MO, 2015 to 2016. Number of Shigella-positive specimens from routine standard of care testing (i.e., culture).

FIG 2

Overall number of subjects in the PRE and POST phases at the Kansas City, MO, site. *, PRE phase: SOC culture performed on 17/110 (15.5%) enrolled subjects. The GI panel detected 10 while SOC culture detected only 8. $, POST phase: SOC culture performed on 20/134 (14.9%) subjects. The GI panel detected 21 while culture detected 17. £, six of the 31 Shigella GI panel-positive samples that received culture assay did not grow Shigella. pos, positive.