Antimicrobial resistance and biotechnological potential of plastic-associated bacteria isolated from an urban estuary.

Plastics have quickly become one of the major pollutants in aquatic environments worldwide and solving the plastic pollution crisis is considered a central goal of modern society. In this study, 10 different plastic samples, including high- and low-density polyethylene and polypropylene, were collected from a deeply polluted urban estuary in Brazil. By employing different isolation and analysis approaches to investigate plastic-associated bacteria, a predominance of potentially pathogenic bacteria such as Acinetobacter, Aeromonas, and Vibrio was observed throughout all plastic samples. Bacteria typically found in the aquatic environment harboured clinically relevant genes encoding resistance to carbapenems (blaKPC ) and colistin (such as mcr-3 and mcr-4), along with genetic determinants associated with potentially active gene mobilization. Whole genome sequencing and annotation of three plastic-associated Vibrio strains further demonstrated the carriage of mobile genetic elements and antimicrobial resistance and virulence genes. On the other hand, bacteria isolated from the same samples were also able to produce esterases, lipases, and bioemulsifiers, thus highlighting that the plastisphere could also be of special interest from a biotechnological perspective.

Antimicrobial resistance and virulence of subgingival staphylococci isolated from periodontal health and diseases.

The dysbiotic biofilm of periodontitis may function as a reservoir for opportunistic human pathogens of clinical relevance. This study explored the virulence and antimicrobial susceptibility of staphylococci isolated from the subgingival biofilm of individuals with different periodontal conditions. Subgingival biofilm was obtained from 142 individuals with periodontal health, 101 with gingivitis and 302 with periodontitis, and cultivated on selective media. Isolated strains were identified by mass spectrometry. Antimicrobial susceptibility was determined by disk diffusion. The mecA and virulence genes were surveyed by PCR. Differences among groups regarding species, virulence and antimicrobial resistance were examined by Chi-square, Kruskal-Wallis or Mann-Whitney tests. The overall prevalence of subgingival staphylococci was 46%, especially in severe periodontitis (> 60%; p < 0.01). S. epidermidis (59%) and S. aureus (22%) were the predominant species across groups. S. condimenti, S. hominis, S. simulans and S. xylosus were identified only in periodontitis. High rates of resistance/reduced sensitivity were found for penicillin (60%), amoxicillin (55%) and azithromycin (37%), but multidrug resistance was observed in 12% of the isolates. Over 70% of the mecA + strains in periodontitis were isolated from severe disease. Higher detection rates of fnB + isolates were observed in periodontitis compared to health and gingivitis, whereas luxF/luxS-pvl + strains were associated with sites with deep pockets and attachment loss (p < 0.05). Penicillin-resistant staphylococci is highly prevalent in the subgingival biofilm regardless of the periodontal status. Strains carrying virulence genes related to tissue adhesion/invasion, inflammation and cytotoxicity support the pathogenic potential of these opportunists in the periodontal microenvironment.