[Analysis of fast-growing culturable bacteria and pathogenic bacteria in the surface water of the northeast coast of Hainan Island in China].

To obtain the diversity and abundance of fast-growing bacteria in the surface water of the northeast coast of Hainan Island in China, different cultivation methods were employed. This study also aims to provide a reference for isolating bacterial samples from seawater sources and preventing marine-derived pathogens. Based on the principles of taxonomic design, surface seawater samples were collected from six locations along the northeast coast of Hainan Island in China in March, June, October, and December 2021. Then, bacterial enrichment was performed based on traditional cultivation methods for , , , , and general marine bacteria. After that, bacterial species identification was conducted by 16S rDNA amplicon sequencing and metagenomic sequencing. A total of 1 151 fast-growing cultivable bacteria belonging to 66 genera and 213 species were identified using five different culture protocols. In different cultivation protocols, and demonstrated extensive discriminatory advantages and ranked among the top genera in terms of abundance. Protocol 1 had , , and as dominant genera. Pathogenic bacteria detected by protocol 1 included and , with 37 and 29 strains respectively, while was uniquely detected with seven isolates. , , and were the dominant genera in protocol 2, and was the most abundant pathogenic bacteria detected with 66 isolates. was uniquely detected with six isolates at a higher abundance. , , and were the dominant genera in protocol 3, and was the most abundant pathogenic bacteria detected with 53 isolates, while was uniquely detected with seven isolates. and were the dominant genera in protocol 4, and they showed advantages in isolating and cultivating Marinederived . , , and were the dominant genera in protocol 5. and were the most abundant pathogenic bacteria detected with 20 and 15 isolates, respectively, while was uniquely detected at higher abundance. Metagenomic sequencing showed that was significantly dominant with a gene abundance of 51.11%, followed by at 12.57%. The surface water of the northeast coast of Hainan Island in China exhibits a rich diversity of bacteria, with being highly abundant in the studied area. Different cultivation methods demonstrate distinct selective advantages in culturing bacterial genera and pathogens. Therefore, it is necessary to optimize cultivation conditions for specific marine bacteria.