Multifunctional polymeric guanidine and hydantoin halamines with broad biocidal activity.

Prolonged and excessive use of biocides during the coronavirus disease era calls for incorporating new antiviral polymers that enhance the surface design and functionality for existing and potential future pandemics. Herein, we investigated previously unexplored polyamines with nucleophilic biguanide, guanidine, and hydantoin groups that all can be halogenated leading to high contents of oxidizing halogen that enables enhancement of the biocidal activity. Primary amino groups can be used to attach poly(N-vinylguanidine) (PVG) and poly(allylamine-co-4-aminopyridine-co-5-(4-hydroxybenzylidene)hydantoin) (PAH) as well as a broad-spectrum commercial biocide poly(hexamethylene biguanide) (PHMB) onto a solid support. Halogenation of polymer suspensions was conducted through in situ generation of excess hypobromous acid (HBrO) from bromine and sodium hydroxide or by sodium hypochlorite in aqueous solutions, resulting in N-halamines with high contents of active > N-Br or > N-Cl groups. The virucidal activity of the polymers against human respiratory coronavirus HCoV-229E increased dramatically with their halogenation. Brominated PHMB-Br showed activation activity value > 5 even at 1 mg/L, and complete virus inhibition was observed with either PHMB-Br or PAH-Br at 10 mg/mL. Brominated PVG-Br and PAH-Br possessed fungicidal activity against C. albicans, while PHMB was fungistatic. PHMB, PHMB-Br and PAH polymers demonstrated excellent bactericidal activity against the methicillin-resistant S. aureus and vancomycin-resistant E. faecium. Brominated polymers (PHMB-Br, PVG-Br, PAH-Br) were not toxic to the HeLa monolayers, indicating acceptable biocompatibility to cultured human cells. With these features, the N-halamine polymers of the present study are a worthwhile addition to the arsenal of biocides and are promising candidates for development of non-leaching coatings.

Genomic characterization of Tenacibaculum maritimum O-antigen gene cluster and development of a multiplex PCR-based serotyping scheme.

Tenacibaculum maritimum is a devastating bacterial pathogen affecting a large variety of marine fish species. It is responsible for significant economic losses in aquaculture farms worldwide. Different typing methods have been proposed to analyse bacterial diversity and population structure. Serological heterogeneity has been observed and up to four different serotypes have been described so far. However, the underlying molecular factors remain unknown. By combining conventional serotyping and genome-wide association study, we identified the genomic loci likely involved in the O-antigen biosynthesis. This finding allowed the development of a robust multiplex PCR-based serotyping scheme able to detect subgroups within each serotype and therefore performs better than conventional serotyping. This scheme was successfully applied to a large number of isolates from worldwide origin and retrieved from a large variety of fish species. No obvious correlations were observed between the mPCR-based serotype and the host species or the geographic origin of the isolates. Strikingly, the distribution of mPCR-based serotypes does not follow the core genome phylogeny. Nevertheless, this simple and cost-effective mPCR-based serotyping method could be useful for different applications such as population structure analysis, disease surveillance, vaccine formulation and efficacy follow-up.