Transcriptomic and phenotypic changes of Cronobacter sakazakii ATCC 29544 grown under desiccation stress
Jae-Ik Lee, Sang‐Soon Kim, Dong‐Hyun Kang
Abstract
In the present study, the effect of desiccation stress on the transcriptomic and phenotypic changes of Cronobacter sakazakii ATCC 29544 was identified. Glucose or lactose was added to the commonly used tryptic soy broth (TSB) to induce desiccation stress (aw = 0.975). From transcriptomic analysis, 126 and 64 upregulated differentially expressed genes (DEGs) were identified for glucose added TSB and lactose added TSB, respectively, and validated by qRT–PCR. Formate metabolism-related genes were highly overexpressed by desiccation stress among the DEGs. When phenotypic changes were investigated, the addition of glucose increased the ratio of unsaturated fatty acids in the membrane lipids of C. sakazakii, which in turn decreased membrane rigidity and made it more susceptible to lipid oxidation. The opposite trend was observed for the pathogen grown in lactose-supplemented TSB. In this regard, the heat resistance of C. sakazakii grown in TSB was lower than that grown in lactose-supplemented TSB, while the opposite trend was observed for the pathogen grown in glucose-supplemented TSB. These results indicated that the transcriptome and phenotype of C. sakazakii would be changed by the materials used to nutrify the pathogen.