Antibiofilm Activity of Antarctic Sponge-Associated Bacteria against Pseudomonas aeruginosa and Staphylococcus aureus

Carmen Rizzo,Concetta Gugliandolo,Salvatore Guglielmino,Vincenzo Zammuto,Pasqualina Laganà,Maria Giovanna Rizzo,Angelina Lo Giudice,Antonio Spanò,Miguel Martinez

doi:10.3390/jmse9030243

Abstract

Bioprospecting in unusual marine environments provides an innovative approach to search novel biomolecules with antibiofilm activity. Antarctic sponge-associated bacteria belonging to Colwellia, Pseudoalteromonas, Shewanella and Winogradskyella genera were evaluated for their ability to contrast the biofilm formation by Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 29213, as model organisms. All strains were able to produce biofilm at both 4 and 25 °C, with the highest production being for Colwellia, Shewanella and Winogradskyella strains at 4 °C after 24 h. Antibiofilm activity of cell-free supernatants (CFSs) differed among strains and on the basis of their incubation temperature (CFSs4°C and CFSs25°C). The major activity was observed by CFSs4°C against S. aureus and CFSs25°C against P. aeruginosa, without demonstrating a bactericidal effect on their growth. Furthermore, the antibiofilm activity of crude extracts from Colwellia sp. GW185, Shewanella sp. CAL606, and Winogradskyella sp. CAL396 was also evaluated and visualized by confocal laser scanning microscopic images. Results based on the surface-coating assay and surface tension measurements suggest that CFSs and the crude extracts may act as biosurfactants inhibiting the first adhesion of P. aeruginosa and S. aureus. The CFSs and the novel biopolymers may be useful in applicative perspectives for pharmaceutical and environmental purposes.

Highlights

Bacterial adhesion and biofilm formation processes have pervasive importance in environmental and human health
Our results suggested that the cell-free supernatants (CFSs) perform antibiofilm activity against P. aeruginosa and S. aureus at the initial phase of biofilm formation interfering with the cellular adhesion on surfaces (Figure 2)
Cold-adapted bacteria belonging to Colwellia, Pseudoalteromonas, Shewanella and Winogradskyella genera, isolated from Antarctic sponges, are able to produce exopolymers allowing them to form biofilm as well as to contrast the biofilm formation of Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 29213, as biofilm models and clinically relevant bacteria

Summary

Introduction

Bacterial adhesion and biofilm formation processes have pervasive importance in environmental and human health. Bacterial biofilms by pathogens represent a serious concern in public health, because they are involved in 65–80% of all human bacterial infections. The biofilm lifestyle protects bacteria from the host immune response and confer them less susceptibility to antimicrobial agents, giving rise to chronic infections that are notoriously difficult to eradicate [6,7,8,9]. Bacterial exopolymers, including exopolysaccharides, involved in the biofilm formation, could possess the ability to counteract the adhesion and the biofilm formation of a wide spectrum of bacteria and fungi [14]. Exopolysaccharides might act as signaling molecules that modulate gene expression of recipient bacteria [15], or in the competitive inhibition of multivalent carbohydrate–protein interactions [16]

Objectives

Discussion

Conclusion