SXP01: A Novel Bacteriophage for Combating Shewanella xiamenensis in Aquaculture

Chen Li¹Yangjun Zhang²Yuyuan Peng³Guofan Zhang²Jiajie Xie²Xinran Long²Linger Qian²Yibo Hu^2*Shengbiao Hu^2*

• ¹Hunan Normal University, Changsha, China
• ²College of Life Science, Hunan Normal University, Changsha, China
• ³College of Life Science,, Hunan Normal University, Changsha, China

Shewanella xiamenensis, a Gram-negative pathogen threatening humans and animals, has developed increasing antibiotic resistance. This has prompted the exploration of bacteriophage therapy as a novel approach to combat multi-drug resistant bacteria. In this study, bacteriophage SXP01, a novel member of the Myoviridae family, was isolated using Shewanella xiamenensis A001, a pathogenic bacterium in aquaculture, as its host. SXP01 demonstrated an optimal multiplicity of infection (MOI) of 0.1, with a 20-minute latent period and a 100-minute burst period. It maintained lytic activity across temperatures (4-60°C), pH levels (6-11), and chloroform concentrations (1%-5%). The phage's lysis cassette includes LysSXP-1 and LysSXP-2, with LysSXP-1 inducing bacterial lysis in E. coli. In vivo trials in crucian carp demonstrated SXP01's efficacy, increasing survival rates from 13.3% to 56.7%. These findings highlight the potential of SXP01 as a targeted biocontrol agent against S. xiamenensis infections in aquaculture, combining genomic novelty, enzymatic synergy, and environmental robustness for sustainable pathogen management.