Effects of chlorination and ultraviolet light on environmental tetracycline-resistant bacteria and tet(W) in water

Abstract

The effectiveness of traditional water disinfection methods against both environmental antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs) is still not well understood. The study objective was to evaluate two common methods for reducing concentrations of not only culturable tetracycline-resistant bacteria but also a resistance tet(W) gene fragment that has been frequently detected in the environment. Disinfection experiments were performed by exposing tetracycline-resistant isolates to various dosages of sodium hypochlorite or ultraviolet irradiation _____________________

Fate of Environmental Pollutants

“…tetracycline and sulphonamide-resistant bacteria (Russo et al, 2017). Another research concluded that despite the high log-reduction of tetracycline-resistant bacteria achieved by UV and chlorination treatment (>4.2-log reduction), "growth and repair" of these bacteria were observed upon UV irradiation (Sullivan et al, 2017). Less consistent results were obtained by these treatments in the case of tetW removal.…”

Chemical Effect of Chlorination Process on Antibiotic Resistant Bacteria

“…Huang et al, [28]and Sullivan et al, [29]showed that, exposing wastewater to chlorine did not select for tetracycline resistant bacteria, and the tetracycline resistant bacteria behaved similarly to that of sensitive bacteria. Also, the same study stated that there is still limited evidence showing that there is any difference between inactivation of antibiotic resistant bacteria and antibiotic sensitive bacteria in sewage to indicate selection of antibiotic resistant bacteria by chlorination.…”

Effects of chlorine, peracetic acid and low-pressure ultra violet light on antibiotic resistant E. coli isolates with regards to their survival and changes in their antibiotic resistance profiles

“…They observed greater than 5 Log10 CFU reduction of E. coli by 0.5mg/L and 1mg/L. Furthermore, a low-pressure UV dose of 69.8 mJ/cm 2 achieved greater than 4 Log10 CFU reduction (Sullivan et al, 2017). The Log10 CFU reduction by low-pressure UV was lower than observed in this study, which could be due to the starting concentration being much higher in the study conducted by Sullivan et al (10 9 CFU/mL versus 10 7 CFU/mL in this study).…”

“…Sullivan et al took their study a step further and analyzed the regrowth of tetracycline resistant E. coli 24 hours after disinfection. While the E. coli exposed to chlorine remained inactivated, those exposed to low-pressure UV experienced significant regrowth, suggesting that chlorine was a more effective treatment in eliminating antibiotic resistant bacteria and mitigating environmental propagation (Sullivan et al, 2017).…”

“…They observed greater than 5 Log10 CFU reduction of E. coli by 0.5mg/L and 1mg/L. Furthermore, a low-pressure UV dose of 69.8 mJ/cm 2 achieved greater than 4 Log10 CFU reduction(Sullivan, Vance, Gentry, & Karthikeyan, 2017).Zhang et al tested the effects of low-pressure UV disinfection on a control (ATCC 25922) and several multi-drug resistant E. coli. Their initial E. coli concentration was 10 9 CFU/100mL, and they tested low-pressure UV doses of 4mJ/cm 2 to 400mJ/cm 2 in a phosphate buffer solution (PBS) matrix.…”