Drying-wetting cycle enhances stress resistance of Escherichia coli O157:H7 in a model soil

Jing Se; Yinan Xie; Qingxu Ma; Lin Zhu; Yulong Fu; Xin Xu; Chaofeng Shen; Paolo Nannipieri

doi:10.1016/j.envpol.2024.123988

Drying-wetting cycle enhances stress resistance of Escherichia coli O157:H7 in a model soil

Environ Pollut. 2024 Apr 20:350:123988. doi: 10.1016/j.envpol.2024.123988. Online ahead of print.

Authors

Jing Se¹, Yinan Xie², Qingxu Ma², Lin Zhu³, Yulong Fu¹, Xin Xu¹, Chaofeng Shen⁴, Paolo Nannipieri⁵

Affiliations

¹ Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, China.
² Ministry of Education Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
³ School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310012, China.
⁴ Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310058, China. Electronic address: ysxzt@zju.edu.cn.
⁵ Emeritus Professor, University of Firenze, Firenze, 50144, Italy.

PMID: 38648967
DOI: 10.1016/j.envpol.2024.123988

Abstract

Outbreaks of Escherichia coli (E. coli) O157:H7 in farms are often triggered by heavy rains and flooding. Most cells die with the decreasing of soil moisture, while few cells enter a dormant state and then resuscitate after rewetting. The resistance of dormant cells to stress has been extensively studied, whereas the molecular mechanisms of the cross-resistance development of the resuscitated cells are poorly known. We performed a comparative proteomic analysis on O157:H7 before and after undergoing soil dry-wet alternation. A differential expression of 820 proteins was identified in resuscitated cells compared to exponential-phase cells, as determined by proteomics analysis. The GO and KEGG pathway enrichment analyses revealed that up-regulated proteins were associated with oxidative phosphorylation, glycolysis/gluconeogenesis, the citrate cycle (TCA cycle), aminoacyl-tRNA biosynthesis, ribosome activity, and transmembrane transporters, indicating increased energy production and protein synthesis in resuscitated O157:H7. Moreover, proteins related to acid, osmotic, heat, oxidative, antibiotic stress and horizontal gene transfer efficiency were up-regulated, suggesting a potential improvement in stress resistance. Subsequent validation experiments demonstrated that the survival rates of the resuscitated cells were 476.54 and 7786.34 times higher than the exponential-phase cells, with pH levels of 1.5 and 2.5, respectively. Similarly, resuscitated cells showed higher survival rates under osmotic stress, with 7.5%, 15%, and 30% NaCl resulting in survival rates that were 460.58, 1974.55, and 3475.31 times higher. Resuscitated cells also exhibited increased resistance to heat stress, with survival rates 69.64 and 139.72 times higher at 55 °C and 90 °C, respectively. Furthermore, the horizontal gene transfer (HGT) efficiency of resuscitated cells was significantly higher (153.12-fold) compared to exponential phase cells. This study provides new insights into bacteria behavior under changing soil moisture and this may explain O157:H7 outbreaks following rainfall and flooding, as the dry-wet cycle promotes stress cross-resistance development.

Keywords: Cross-resistance; Dormancy; Dry-wet cycle; Resuscitation; Soil proteomics.