| Title | Cryptic prophages in a blaNDM-1-bearing plasmid increase bacterial survival against high NaCl concentration, high and low temperatures, and oxidative and immunological stressors |
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| Author | So Yeon Kim1 and Kwan Soo Ko2* |
| Address | 1Division of Bacterial Disease Research, Center for Infectious Disease Research, Korea National Institute of Health, Center for Disease Control and Prevention, Cheongju 28159, Republic of Korea, 2Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea |
| Bibliography | Journal of Microbiology, 58(6),483–488, 2020, |
| DOI | 10.1007/s12275-020-9605-6 |
| Key Words | NDM-1, plasmid, cryptic prophage, sigma factor, general stress response |
| Abstract | In this study, we investigated the effect of cryptic prophage regions in a blaNDM-1-bearing plasmid, which was identified in a patient from South Korea, on the survival of bacteria against adverse environmental conditions. First, we conjugated the intact plasmid and plasmids with deleted cryptic prophages into Escherichia coli DH5α. The E. coli transconjugants carrying the plasmid with intact cryptic prophages showed increased survival during treatment with a high concentration of NaCl, high and low temperatures, an oxidative stressor (H2O2), and an immunological stressor (human serum). By contrast, the transconjugants carrying the plasmid with a single-cryptic prophage knockout did not show any change in survival rates. mRNA expression analyses revealed that the genes encoding sigma factor proteins were highly upregulated by the tested stressors and affected the expression of various proteins (antioxidant, cell osmosis-related, heat shock, cold shock, and universal stress proteins) associated with the specific defense against each stress. These findings indicate that a bacterial strain carrying a plasmid with intact carbapenemase gene and cryptic prophage regions exhibited an increased resistance against simulated environmental stresses, and cryptic prophages in the plasmid might contribute to this enhanced stress resistance. Our study indicated that the coselection of antibiotic resistance and resistance to other stresses may help bacteria to increase survival rates against adverse environments and disseminate. |