Photoinactivation of Pseudomonas aeruginosa Biofilm by Dicationic Diaryl-Porphyrin.

Viviana Teresa Orlandi,Nicola Trivellin,Enrico Caruso,Eleonora Martegani,Francesco Garzotto,Fabrizio Bolognese

doi:10.3390/ijms22136808

Abstract

In recent years, antimicrobial photodynamic therapy (aPDT) has received increasing attention as a promising tool aimed at both treating microbial infections and sanitizing environments. Since biofilm formation on biological and inert surfaces makes difficult the eradication of bacterial communities, further studies are needed to investigate such tricky issue. In this work, a panel of 13 diaryl-porphyrins (neutral, mono- and di-cationic) was taken in consideration to photoinactivate Pseudomonas aeruginosa. Among cationic photosensitizers (PSs) able to efficiently bind cells, in this study two dicationic showed to be intrinsically toxic and were ruled out by further investigations. In particular, the dicationic porphyrin (P11) that was not toxic, showed a better photoinactivation rate than monocationic in suspended cells. Furthermore, it was very efficient in inhibiting the biofilms produced by the model microorganism Pseudomonas aeruginosa PAO1 and by clinical strains derived from urinary tract infection and cystic fibrosis patients. Since P. aeruginosa represents a target very difficult to inactivate, this study confirms the potential of dicationic diaryl-porphyrins as photo-activated antimicrobials in different applicative fields, from clinical to environmental ones.

Highlights

All of them have been recently reported by the World Health Organization (WHO) in the list of the 12 bacterial species against which new antibiotics are urgently needed [3]
The positive charge of cationic diaryl-porphyrins derives from a pyridinium group
Images of biofilms are shown in volume view, and in xy, xz and yz projections

Summary

Introduction

The term “ESKAPE” arises from the following six name species: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp [1]. These bacterial species are associated with most of nosocomial infections and the highest risk of mortality [2]. P. aeruginosa, thanks to its wide genome (5–7 Mbp), displays a wide capacity to use various carbon sources and adapts to several environments including soils, waters, sewages and is a common part of the microflora of different animals. The highest part of its genome is dedicated to regulatory genes and networks that are fundamental for the response and adaptation to different and changing environments [4]

Methods

Results

Conclusion