Identification and molecular characterization of Serratia marcescens phages vB_SmaA_2050H1 and vB_SmaM_2050HW
Serratia marcescens is a rod-shaped, Gram-negative bacterium causing nosocomially acquired infections. Bacteriophages are natural opponents of their pathogenic bacterial hosts and could be an alternative to traditional antibiotic treatments. In this study, two S. marcescens-specific bacteriophages, vB_SmaA_2050H1 and vB_SmaM_2050HW, were isolated from two different waste samples in China. Phage plaque assays, transmission electron microscopy, host-range determination, and one-step growth curve analyses were performed for both phages. vB_SmaA_2050H1 was classified as belonging to the family Ackermannviridae, and vB_SmaM_2050HW was classified as belonging to the family Myoviridae. One-step growth curve analysis showed that the latent and rise period of vB_SmaA_2050H1 were 80 min and 50 min, respectively, with a burst size of approximately 103 phage particles per infected cell. For vB_SmaM_2050HW, latent and rise periods of 40 min and 60 min, respectively, were determined, with a burst size of approximately 110 phage particles per infected cell. vB_SmaA_2050H1 infected 10 of the 15 (66.67%) S. marcescens strains tested, while vB_SmaM_2050HW infected 12 (80%) of the strains. Whole-genome sequencing and annotation of each of the phage genomes revealed genome sizes of 159,631 bp and 276,025 bp for vB_SmaA_2050H1 and vB_SmaM_2050HW, respectively, with the respective genomes containing 213 and 363 putative open reading frames. Sequence analysis of the genomes revealed that vB_SmaA_2050H1 is a member of the ViI-like family, while vB_SmaM_2050HW is a novel virulent bacteriophage. These findings provide further insights into the genomic structures of S. marcescens bacteriophages.
We would like to thank the Center for Biological Imaging (CBI), Institute of Biophysics, Chinese Academy of Science, for electron microscopy work, and we are grateful to Deyin Fan for his help in making EM samples. We thank Tamsin Sheen, PhD, from Liwen Bianji, Edanz Editing China (http://www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.
CT and JZ did the experiments and contributed equally to this study as joint first authors. ZZ, XC, XW, HL, WL, YK, AJ, LH, WY, YJ and YL analyzed the data. FR and JY provided the bacterial strains. XZ managed the project and designed the experiments. CT, JZ and XZ wrote the article.
This work received support from National Natural Science Foundation of (China Grant 31670174).
Compliance with ethical standards
Conflict of interest
The authors declare no potential conflicts of interest.
Availability of data and materials
The sequences of vB_SmaA_2050H1and vB_SmaM_2050HW were submitted to the GenBank nucleotide sequence database under accession numbers MF285619 and MF285618.
Research involving human participants and/or animals
This article does not contain any studies with animals performed by any of the authors.
Informed consent was obtained from all individual participants included in the study.
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