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 Campylobacter jejuni. Exposure to a low concentration (0.4 mg/L) of dissolved ClO2 for 2 h resulted in a >93% reduction of C. jejuni, 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 C. jejuni responds to ClO2-induced oxidative stress by upregulating genes involved in reactive oxygen species (ROS) detoxification (sodB, ahpC, katA, msrP, and trxB), iron transport (ceuBCD, cfbpABC, and chuBCD), phosphate transport (pstSCAB), and DNA repair (rdgB and mutY). Reverse transcription-quantitative PCR (RT-qPCR) validated the increased expression of oxidative stress response genes but not general stress response genes (spoT, dnaK, and groES). These findings provide insights into the antimicrobial mechanism of ClO2, demonstrating that oxidative damage to essential cellular components results in bacterial cell death.