Insights into diversity and plastic substrate specificity of potential pathogenic bacteria

Abstract

To understand the diversity and the substrate specificity of potentially pathogenic bacteria (PPB) in floating marine plastic debris off the Southern coastal waters of South Korea, a total of 600 pieces of plastics were collected from the coastal waters and bacterial diversity was analyzed through 16s rDNA metabarcoding. Additionally, as a control, ambient seawater around plastic litter was collected and analyzed. The dominant bacterial community in the seawater was Alphaproteobacteria, while there was Gammaproteobacteria in the plastisphere. The bacterial community in the plastisphere showed no significant differences by investigated areas and plastic materials (ANOVA, p>0.05). However, it was significantly divided into four groups according to the temperature of the ambient seawater (p<0.01). PPB appeared at 157 ASVs, 2.9% in the total bacterial community, on means of 16.2% in plastispheres and 4.8% in seawater. When Venn diagram analysis was performed, the core PPB that commonly appeared in all four plastic materials (PE, PP, PET, and EPS) was 72 ASVs and mostly composed of Pseudoalteromonas and Vibrios. In addition, PPB showed a higher proportion during lower water temperature periods. These litters may act as vectors for pathogen transport, and core PPB may play a core role in pathogenicity during low-temperature periods in the plastisphere.