Transcriptomic Analysis of Campylobacter jejuni Following Exposure to Gaseous Chlorine Dioxide Reveals an Oxidative Stress Response

Gaseous chlorine dioxide (ClO₂) is a potent antimicrobial agent used to control microbial contamination in food and water. This study evaluates the bactericidal activity of gaseous ClO₂ released from a sodium chlorite (NaClO₂) pad against <i>Campylobacter jejuni</i>. Exposure to a low concentration (0.4 mg/L) of dissolved ClO₂ for 2 h resulted in a >93% reduction of <i>C. jejuni</i>, highlighting the bacterium's extreme sensitivity to gaseous ClO₂. To elucidate the molecular mechanism of ClO₂-induced bactericidal action, transcriptomic analysis was conducted using RNA sequencing (RNA-seq). The results indicate that <i>C. jejuni</i> responds to ClO₂-induced oxidative stress by upregulating genes involved in reactive oxygen species (ROS) detoxification (<i>sodB</i>, <i>ahpC</i>, <i>katA</i>, <i>msrP</i>, and <i>trxB</i>), iron transport (<i>ceuBCD</i>, <i>cfbpABC</i>, and <i>chuBCD</i>), phosphate transport (<i>pstSCAB</i>), and DNA repair (<i>rdgB</i> and <i>mutY</i>). Reverse transcription-quantitative PCR (RT-qPCR) validated the increased expression of oxidative stress response genes but not general stress response genes (<i>spoT</i>, <i>dnaK</i>, and <i>groES</i>). These findings provide insights into the antimicrobial mechanism of ClO₂, demonstrating that oxidative damage to essential cellular components results in bacterial cell death.