Gastrointestinal illness has many aetiological agents including bacteria, viruses and parasites. Severity of disease ranges from mild to severe depending on the causal agent. Thus it is important to correctly identify the cause of infection, allowing for effective treatment and preventing antibiotic over-prescription. The current gold standard of identification is both slow and subjective. A more rapid, sensitive and specific alternative is the molecular diagnosis of infection using the polymerase chain reaction (PCR).

The Bioline multiplex PCR kit was compared to standard culture methods and in house PCR for the detection of Campylobacter spp, Salmonella spp, Shigella spp and Yersinia enterocolitica in stool specimens. A total of 96 specimens, previously analysed by microscopy and culture for the routine diagnosis of gastroenteritis, were tested in this study. A true positive result was considered to be any specimen that was positive by any two of the three assays used.

The Bioline multiplex PCR detected Campylobacter in 31/32 (96.9%) specimens of which 29 were previously detected by culture. One culture positive specimen was positive by the in house assay but not the Bioline assay. Salmonella was detected in 39/39 (100%) of culture positives, with a further 3 positives detected, 2 by both PCR’s and 1 by the Bioline PCR only. The Shigella PCR tested positive for 3/3 (100%) of culture positive specimens. For Yersinia enterocolitica 1/1 (100%) culture positive was detected by the PCR as well as 1 positive not detected by culture. While studies are still ongoing, the preliminary data indicates that the Bioline multiplex PCR assay showed an improved performance over bacterial culture, with comparable results to the in-house PCR. However, the Bioline multiplex kit was more cost effective than the Singleplex in house assays, and proved to be a faster and improved means of identifying the causal agent in gastroenteritis.