Inactivation of Antibiotic Resistant Bacteria and Resistance Genes by Ozone: From Laboratory Experiments to Full-Scale Wastewater Treatment

Abstract

Ozone, a strong oxidant and disinfectant, seems ideal to cope with future challenges of water treatment, such as micropollutants, multiresistant bacteria (MRB) and even intracellular antibiotic resistance genes (ARG), but information on the latter is scarce. In ozonation experiments we simultaneously determined kinetics and dose-dependent inactivation of Escherichia coli and its plasmid-encoded sulfonamide resistance gene sul1 in different water matrixes. Effects in E. coli were compared to an autochthonous wastewater community. Furthermore, resistance elimination by ozonation and post-treatment were studied in full-scale at a wastewater treatment plant (WWTP). Bacterial inactivation (cultivability, membrane damage) and degradation of sul1 were investigated using plate counts, flow cytometry and quantitative real-time PCR. In experiments with E. coli and the more ozone tolerant wastewater community disruption of intracellular genes was observed at specific ozone doses feasible for full-scale application, but flocs seemed to interfere with this effect. At the WWTP, regrowth during postozonation treatment partly compensated inactivation of MRB, and intracellular sul1 seemed unaffected by ozonation. Our findings indicate that ozone doses relevant for micropollutant abatement from wastewater do not eliminate intracellular ARG.

Removing Antibiotic-Resistant Bacteria (ARB) Carrying Genes (ARGs): Challenges and Future Trends

“…In this regard, it is advised to define principle-based kinetic parameters for ARG demobilization in clean water matrixes (such as no oxidant demand). At most, few investigations have accurately defined commonly viable rate constants for ARG demobilization, like for ozonation [35] and UV disinfection [39] [52]. To conclude, regardless of huge modern research advance, it remains hard to foresee the demobilization degrees of varying sorts of ARGs throughout wastewater disinfection or oxidation at a changing running technique or water matrix situations [1].…”

Genomic and Metagenomic Approaches for Predictive Surveillance of Emerging Pathogens and Antibiotic Resistance

“…Although wastewater is treated to eliminate coliform bacteria, treatments may be ineffective at destroying ARGs, resulting in ARG enrichment in surviving wastewater microbes. [55][56][57] Further, functional metagenomic studies (methods described below) have identified increases in phenotypically resistant clones recovered from samples downstream of wastewater treatment plants, suggesting that wastewater treatment and disposal increases the reservoir of resistance mechanisms in the environment. 58 One recent study used metagenomics to better understand ARO and ARG abundance in the Chaobia River, a major source of drinking water, agricultural irrigation, and waste in China.…”

Using indicators to assess microbial treatment and disinfection efficacy

“…In addition, a total ozone dose of 66.0 mgO 3 ·gVSS-1 (ozone dose rate of 3.3 mgO 3 ·gVSS-1·min-1 for a contact time of 20 min) were found to be the most suitable conditions to control filamentous bulking. Czekalski et al (2016) revealed that due to its strong oxidant and disinfectant effects, ozone can be seen as an ideal way to face emerging challenges of water treatment namely multiresistant bacteria (MRB) and even intracellular antibiotic resistance genes (ARG). During their experiment, E. coli inactivation and ARG disruption were noted at specific ozone doses feasible for full-scale application.…”