Detection of a putative virulence cadF gene of Campylobacter jejuni obtained from different sources using a microfabricated PCR chip

A microfabricated polymerase chain reaction (PCR) chip made of epoxybased photoresist (SU-8) was recently designed and developed. In this study, we tested whether the PCR chip could be used for rapid detection of a potential virulence determinant, the cad F gene of Campylobacter jejuni . PCR was performed using published PCR conditions and primers for the C. jejuni cad F gene. DNA isolated from a C. jejuni reference strain CCUG 11284, C. jejuni isolates obtained from different sources (chicken and human), and Campylobacter whole cells were used as templates in the PCR tests. Conventional PCR in tube was used as the control. After optimization of the PCR chip, PCR positives on the chip were obtained from 91.0% (10/11) of the tested chips. A fast transition time was achieved with the PCR chip, and therefore a faster cycling time and a shorter PCR program were obtained. Using the PCR chip, the cad F gene could be detected in 1.5 h in comparison to 3.4 h in the published methods. The PCR chip can be applied for rapid detection of the virulence cad F gene of C. jejuni obtained from different sources. This is the first PCR chip that has been used to detect Campylobacter virulence genes. Using the chip, the cad F gene of C. jejuni can be detected directly from bacterial whole cells without DNA isolation and purification steps.