Isolation and identification of bacteria in seawater and their antibacterial activity on animal pathogens
In order to isolate marine bacteria with bacteriostatic activity,M10 medium,P3 medium and BHI solid medium were used to isolate bacteria from seawater samples,and bacteria with bacteriostatic activity against Escherichia coli,Pseudomonas aeruginosa,Staphylococcus aureus and Listeria monocytogenes were screened from isolated bacteria by solid agar punching,and 16S rDNA genes of bacteriostatic bacteria were amplified by PCR and sequence analysis was carried out.The results showed that a total of 1 615 strains of bacteria were isolated from seawater in Zhanjiang area,of which 246 strains had antibacterial activity and 6 strains had antibacterial effect on all four index bacteria.The diameter of the inhibitory circle of the strain DB17-1 with the best antibacterial effect on Escherichia coli was 26 mm,the strain FP5-2 with the best antibacterial effect against Staphylococcus aureus was 29 mm in the inhibition circle diameter,the strain AM20-8 with the best antibacterial effect against Pseudomonas aeruginosa had a diameter of 20 mm,and the strain FM11-1 with the best antibacterial effect against Listeria monocytogenes had a diameter of 24 mm.The bacteriostatic bacteria were divided into 31 genera,among which Acinetobacter and Bacillus accounted for the most,accounting for 21.5%and 18.3%,respectively.There are bacteria with good antibacterial effect in seawater,and the research results can provide a theoretical basis for the discovery of new antibacterial drugs.