RNA seq analysis after treated with DATS in Campylobacter

Campylobacter jejuni is an important foodborne pathogen causing Campylobacteriosis in humans by consuming contaminated chicken products or directly handling animals. DATS is a trisulfide compound from garlic extracts which has a potential antimicrobial effect to the foodborne pathogens. This study investigated the antimicrobial activity of DATS on C. jejuni by evaluating the minimal inhibitory concentrations (MICs) of C. jejuni NCTC 81-168 and fourteen C. jejuni isolates from chicken carcasses. Thirteen out of 14 C. jejuni isolates and NCTC 81-176 had MICs = 32 µg/mL, while one isolate had MIC of 64 µg/mL. Scanning electron microscopy (SEM) analysis showed the disruption and shrink of C. jejuni bacterial cell membrane after the DATS treatment. The further time-killing analysis showed that DATS have an increasing antimicrobial effect on C. jejuni with the increasing of the concentration during the 24 h treatment period in vitro. In addition, DATS also showed an antimicrobial effect in chicken by the decrease of C. jejuni colony count by 1.5 log CFU/g (cloacal sample) during the seven-day DATS treatment period. The transcriptional analysis of C. jejuni with 16 µg/mL (0.5× MIC) showed 210 differentially expression genes (DEGs), which were mainly related to the metabolism, bacterial membrane transporter system and the secretion system. The activity of fourteen ABC transporter-related genes were down regulated indicating that DATS could decrease the bacterial cell homeostasis and the ability to against oxidative stress. We further constructed five ABC transporter deletion mutants according to the RNA-seq analysis, and all five mutants showed less tolerance to the DATS treatment compared to the wild type by MIC test. This study elucidated the antimicrobial activity of DATS on C. jejuni, which provided evidence for using DATS as a potential antimicrobial compound in the animal feed and food industry.