Characterization of the Bacterial Biofilm Communities Present in Reverse-Osmosis Water Systems for Haemodialysis

Abstract

Biofilm in reverse osmosis (RO) membranes is a common problem in water treatment at haemodialysis facilities. Bacteria adhere and proliferate on RO membranes, forming biofilms, obstructing and damaging the membranes and allowing the transfer of bacteria and/or cellular components potentially harmful to the health of haemodialysis patients. Our aim was to characterize the bacterial community associated to biofilm of RO membranes and to identify potentially pathogenic bacteria present in the haemodialysis systems of two dialysis centres in Chile. The diversity of the bacterial communities present on RO membranes and potable and osmosed water samples was evaluated using Illumina sequencing. Additionally, bacteria from potable water, osmosed water and RO membrane samples were isolated, characterized and identified by Sanger’s sequencing. The molecular analyses of metagenomics showed that the phyla having a greater relative abundance in both dialysis centres were Proteobacteria and Planctomycetes. Pseudomonas, Stenotrophomonas, Agrobacterium, Pigmentiphaga, Ralstonia, Arthrobacter, Bacteroides and Staphylococcus were bacterial genera isolated from the different samples obtained at both haemodialysis centres. Pseudomonas spp. was a bacterial genus with greater frequency in all samples. Pseudomonas and Staphylococcus showed higher levels of resistance to the antibiotics tested. Results demonstrated the presence of potentially pathogenic bacteria, showing resistance to antimicrobials on RO membranes and in osmosed water in both dialysis centres studied.

Gastrointestinal Microbiota and Parasite-Fauna of Wild Dissostichus eleginoides Smitt, 1898 Captured at the South-Central Coast of Chile

“…16S rRNA universal primers EUB 9-27 and EUB 1542 were used for amplification of DNA [31]. Then, Nested PCR was performed using the primer pair 341f and 534r with a GC clamp (CGCCC GCCGC GCGCG GCGGG CGGGG CGGGG GCACG GG GGG) according to Cuevas et al [32]. DGGE was performed with a DGGE 1001 system (C.B.S.…”

“…For the analysis of banding profiles, a binary matrix was constructed based on the presence (1) or absence (0) of individual bands in each lane using the Gel-Pro Analyzer 4.0 software package (Media Cybernetics, Silver Spring, MD, USA). A multidimensional scaling diagram (MDS) was constructed using the Bray Curtis algorithm, according to Cuevas et al [32].…”

A laboratory ice machine as a cold oligotrophic artificial microbial niche for biodiscovery

“…Biofilms are well known for their ability to overgrow and clog artificial substrates such as intermittent sand filters, in which clogging as a consequence of heterotrophs growth occurred in the upper part of the system 5 . They can also be responsible for the clogging of water distribution systems in drip irrigation emitters of treated wastewater 6 ; the obstruction and contamination of machines such as reverse-osmosis water systems used for haemodialysis 7 ; or cause runability problems in paper machines 8 . Biofilm development in artificial environments and mechanical devices, particularly those with high water loads, can yield to the risk of contamination by pathogens, for example in dishwashers 9 , 10 .…”

Detection and characterization of Bacillus cereus isolated from the dialysis fluid

“…Despite the numerous barriers present in the treatment system to remove microorganisms from the water, there is a risk of contamination if the system is not efficient 2 . In addition, contamination by a biofilm-forming microorganism can persist at various points along the treatment system and increase the resistance to disinfection and antimicrobial procedures, leading to endotoxemia and/or infection 3 . The aim of this study was to detect, identify and analyze the conditions of virulence, biofilm formation and susceptibility profile to antimicrobial agents of Bacillus cereus .…”