A Multi-Purpose Approach to the Mechanisms of Action of Two Biocides (Benzalkonium Chloride and Dibromonitrilopropionamide): Discussion of Pseudomonas fluorescens' Viability and Death

• Type: Article in International Scientific Journal
• Date: 2022-02-18

Authors

Luis F. Melo (Author) FEUP; Ana C. Barros (Author) FEUP; Ana Pereira (Author) FEUP

Journal

Title: Frontiers in Microbiology

Vol. 148

Pages: 1-13

ISSN: 1664-302X

Publisher: FRONTIERS MEDIA SA

Indexing

ISI Web of Knowledge - 0 Citations

Associated Projects

pBio4.0 - Prevenir o Biosujamento em Sistemas de Membranas

Other information

Authenticus ID: P-00W-9MF

DOI: 10.3389/fmicb.2022.842414

Abstract (EN): Biocides are widely used in water treatment for microbiological control. The rise of antimicrobial resistance and the need to assure properly managed water systems require a better understanding of the mechanisms of action of biocides and of their impact on cell's viability as a function of dosage concentrations. The present work addresses these two aspects regarding the biocides benzalkonium chloride (BAC) and dibromonitrilopropionamide (DBNPA)-two biocides commonly found in the water treatment industry. For that, the following parameters were studied: culturability, membrane integrity, metabolic activity, cellular energy, and the structure and morphology of cells. Also, to assess cell's death, a reliable positive control, consisting of cells killed by autoclave (dead cells), was introduced. The results confirmed that BAC is a lytic biocide and DBNPA a moderate electrophilic one. Furthermore, the comparison between cells exposed to the biocides' minimum bactericidal concentrations (MBCs) and autoclaved cells revealed that other viability parameters should be taken into consideration as "death indicators." The present work also shows that only for the concentrations above the MBC the viability indicators reached values statistically similar to the ones observed for the autoclaved cells (considered to be definitively dead). Finally, the importance of considering the biocide mechanism of action in the definition of the viability parameter to use in the viable but non-culturable (VBNC) determination is discussed.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13