Inactivation of antibiotic-resistant bacteria by chlorine dioxide in soil and shifts in community composition

Abstract

To study the efficacy of chlorine dioxide in the inactivation of antibiotic-resistant bacteria in soil, bacteria resistant to penicillin, amoxicillin or streptomycin were screened out from the soils around a hennery. The effects of dosage, contact time and pH value on the killing rates were investigated by batch experiments. The community composition before and after inactivation was analyzed by high-throughput genetic sequencing. The results showed that antibiotic-resistant bacteria are common and widespread in soil and the most resistant species is Staphylococcus aureus. More than 99% of antibiotic-resistant bacteria could be killed by chlorine dioxide at 5 mg L⁻¹ within 30 min under neutral conditions. The killing log value declined slightly when the pH was changed from 4 to 9. The dominant genus was Sphingomonas, which was sensitive to chlorine dioxide and could be inactivated easily similar to Arthrobacter and Massilia. However, Micromonosporaceae and Thaumarchaeota were more resistant to chlorine dioxide than other species, and their relative abundance increased after disinfection.