Detection of Shigella sonnei in selected foods by flow-through immunocapture followed by real-time polymerase chain reaction or isolation on MacConkey agar.

摘要

This study compared the flow-through immunocapture (FTI), using the Pathatrix, followed by plating on MacConkey agar (FTI-MAC) or analysis by real-time polymerase chain reaction (FTI-PCR) to the Food and Drug Administration's Bacteriological Analytical Manual (BAM) Shigella culture method for the detection of Shigella sonnei on tomatoes, in potato salad and in ground beef. For tomatoes, the FTI-MAC and FTI-PCR achieved significantly improved detection (P<0.05) of S. sonnei over the BAM. For potato salad, there was no significant difference among the 3 methods (P>0.05). For ground beef, FTI-MAC was not significantly different (P>0.05) than the BAM for the detection of S. sonnei; however, FTI-PCR was superior (P<0.05). No tomato and only one potato salad sample resulted in the isolation of background microflora by FTI-MAC. In contrast, the analysis of ground beef by FTI-MAC resulted in consistent isolation of background microflora with or without co-isolation of S. sonnei. It is suggested that the FTI-PCR method can be used as a rapid method for the detection of S. sonnei as final results were obtained within 24 h..