The effects of sodium hypochlorite against selected drinking water-isolated bacteria in planktonic and sessile states

• Type: Article in International Scientific Journal
• Date: 2016

Authors

I. B. Gomes (Author) Other; L. C. Simões (Author) FEUP; M. Simões (Author) FEUP

Journal

Title: Science of the Total Environment

Vol. 565

Pages: 40-48

ISSN: 0048-9697

Publisher: Elsevier

Indexing

ISI Web of Science

Scopus

Associated Projects

POMACEA - Tecnologias económicas para controlo de (bio)fouling em membranas através da otimização de métodos de pré-tratamentos de limpeza

LEPABE - Laboratório de Engenharia de Processos, Ambiente, Biotecnologia e Energia

Other information

DOI: 10.1016/j.scitotenv.2016.04.136

Abstract (EN): Chlorine is the most commonly used agent for general disinfection, particularly for microbial growth control in drinking water distribution systems. The goals of this study were to understand the effects of chlorine, as sodium hypochlorite (NaOCl), on bacterial membrane physicochemical properties (surface charge, surface tension and hydrophobicity) and on motility of two emerging pathogens isolated from drinking water, Acinetobacter calcoaceticus and Stenotrophomonas maltophilia. The effects of NaOCl on the control of single and dual-species monolayer adhered bacteria (2 h incubation) and biofilms (24 h incubation) was also assessed. NaOCl caused significant changes on the surface hydrophobicity and motility of A. calcoaceticus, but not of S. maltophilia. Planktonic and sessile S. maltophilia were significantly more resistant to NaOCl than A. calcoaceticus. Monolayer adhered co-cultures of A. calcoaceticus-S. maltophilia were more resilient than the single species. Oppositely, dual species biofilms were more susceptible to NaOCl than their single species counterparts. In general, biofilm removal and killing demonstrated to be distinct phenomena: total bacterial viability reduction was achieved even if NaOCl at the higher concentrations had a reduced removal efficacy, allowing biofilm reseed. In conclusion, understanding the antimicrobial susceptibility of microorganisms to NaOCl can contribute to the design of effective biofilm control strategies targeting key microorganisms, such as S. maltophilia, and guarantying safe and high-quality drinking water. Moreover, the results reinforce that biofilms should be regarded as chronic contaminants of drinking water distribution systems and accurate methods are needed to quantify their presence as well as strategies complementary/alternative to NaOCl are required to effectively control the microbiological quality of drinking water.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9