Response of Freshwater Biofilms to Antibiotic Florfenicol and Ofloxacin Stress: Role of Extracellular Polymeric Substances

Abstract

Antibiotic residues have been detected in aquatic environments worldwide. Biofilms are one of the most successful life forms, and as a result are ubiquitous in natural waters. However, the response mechanism of freshwater biofilms to the stress of various antibiotic residues is still unclear. Here, the stress of veterinary antibiotic florfenicol (FF) and fluoroquinolone antibiotic ofloxacin (OFL) on freshwater biofilms were investigated by determining the changes in the key physicochemical and biological properties of the biofilms. The results showed that the chlorophyll a content in biofilms firstly decreased to 46–71% and then recovered to original content under the stress of FF and OFL with high, mid, and low concentrations. Meanwhile, the activities of antioxidant enzymes, including superoxide dismutase and catalase, increased between 1.3–6.7 times their initial values. FF was more toxic to the biofilms than OFL. The distribution coefficients of FF and OFL binding in extracellular polymeric substances (EPS)-free biofilms were 3.2 and 6.5 times higher than those in intact biofilms, respectively. It indicated that EPS could inhibit the FF and OFL accumulation in biofilm cells. The present study shows that the EPS matrix, as the house of freshwater biofilms, is the primary barrier that resists the stress from antibiotic residues.

Antibiotics modulate biofilm formation in fish pathogenic isolates of atypical Aeromonas salmonicida

“…Increased biofilm may be a response to stress detected through the inhibition of growth, and antibiotic concentrations causing greatest stress will likely be close to those arresting growth completely (Bernier & Surette, 2013). Bacteria in biofilms are better protected against environmental insults such as antibiotics, as far greater concentrations are needed to kill cells in a biofilm compared with a planktonic existence (Davey & O’Toole, 2000; Olsen, 2015; Olson, Ceri, Morck, Buret, & Read, 2002), while increased production of extracellular polymeric substances by bacteria growing in a biofilm provides one explanation because this can bind antibiotics to prevent penetration into the biofilm structure (Mulcahy, Charron‐Mazenod, & Lewenza, 2008; Olsen, 2015; Wang et al., 2019). Bacteria growing in biofilms show other alterations in behaviour and gene expression that can further explain decreased susceptibility to antibacterial agents including reduced metabolism (Knudsen, Fromberg, Ng, & Gram, 2016; Olsen, 2015; Song et al., 2016; Sun, Chen, Lin, & Lin, 2017).…”

Resilience and limitations of MFC anodic community when exposed to antibacterial agents

“…Previous research has shown that bioelectrochemical systems such as microbial fuel cells are capable of degrading different pharmaceuticals. Amongst these are ampicillin [11] , sulphonamides [37] , Florfenicol and Ofloxacin [38] . Reports by Zhou et al [39] on the electrochemical responses of antibiotics addition to MFCs with developed anode showed that lower concentration of antibiotics resulted in greater power generation, whilst higher concentrations generated at slightly lower voltage levels.…”

Emerging Technologies in Algal Biotechnology: Toward the Establishment of a Sustainable, Algae-Based Bioeconomy

“…Microalgae possess a large number of enzymes that play a role in cellular protection through the deactivation and/or degradation of a range of organic compounds that induce cellular stress in microalgae . Microalgal degradation of ECs relies on a complex enzymatic process involving a number of enzymes, including: superoxide dismutase, catalase, glutamyl-tRNA reductase, malate/pyruvate dehydrogenase, mono(di)oxygenase, pyrophosphatase, carboxylase/decarboxylase, dehydratase, alkaline and acid phosphatase, transferase, and hydrolases (Elbaz et al, 2010;Xiong et al, 2018;Wang et al, 2019). Several of these enzymes, including superoxide dismutase and catalase, have shown increased activity in several freshwater microalgal species, when the cells were exposed to the veterinary antibiotics Florfenicol and Ofloxacin .…”