Abstract
Background
Multiplexed molecular panels allow rapid detection of multiple stool pathogens, reducing workload and turn around time compared to conventional methods. This study evaluated the performance of Seegene Allplex™ GI-Bacteria (I) and (II) panels and Roche LightMix® gastrointestinal bacterial assays.
Methods
A total of 233 frozen, pre-characterized clinical or simulated Copan FecalSwab® specimens were tested on Allplex™ panels, while 219 were tested on LightMix® panels. Fecal swab fluid (190uL) was combined with 10uL of each Allplex™ GI-BP internal control and LightMix® phocine herpesvirus extraction control and extracted on the Roche MagNA Pure Compact. PCR was performed in parallel on the Bio-Rad CFX96 and LightCycler 480II, using reaction parameters specified by the manufacturers. Campylobacter spp, Salmonella spp, Shigella spp, Y. enterocolitica, Aeromonas spp and Shiga toxin 1/2 genes were compared between both assays, with C. difficile, Vibrio spp and E. coli O157 only evaluated on Allplex™ and P. shigelloides only evaluated on LightMix®. Sensitivity and specificity were calculated using a modified gold standard, composed of at least 2 positive between routine stool culture, Allplex™ and LightMix® PCR.
Results
Allplex™ panels provided accurate results in 192/198 (97%) clinical specimens while LightMix® was accurate in 183/189 (96.8%). When both clinical and simulated specimens were considered, Allplex™ had excellent performance for all targets, apart from Campylobacter spp (87.5% sensitivity) and Vibrio spp (66.7% sensitivity), since more unusual species (eg: C. upsaliensis, V. fluvialis) were not detected (Table 1). LightMix® performed well with >90% sensitivity and >99% specificity for all targets.
Conclusions
Both assays performed well in detecting clinically relevant infections, compared to conventional methods.
