Sulfadiazine degradation by Acinetobacter sp. strain H-3 and its applicability in soil at low temperatures

Abstract

The prolonged and widespread use of veterinary antibiotics resulted in a significant accumulation of antibiotic residues in the soil surrounding poultry farms, thereby promoting the proliferation and dissemination of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB). In the northern regions of China, low temperatures hinder the microbial degradation of antibiotics. This study reports that Acinetobacter sp. H-3, isolated from a poultry farm in Liaoning Province, Northeast China, is capable of effectively degrading SDZ at a minimum temperature of 5°C, with optimal degradation efficiency observed at 15°C. The strain H-3 removed 82% of SDZ from the soil over a 14-day period at 15°C, with 53% of this degradation directly attributed to the activity of strain H-3. High-throughput sequencing and RT-qPCR analyses revealed that exposure to SDZ significantly altered the soil bacterial community structure, inhibited soil microbial functions and increased the abundance of sul1, sul2 and intI1 genes. Following the application of, certain bacterial genera in the contaminated soil exhibited indications of recovery. However, the overall soil microbial function did not show a recovery trend. Additionally, the presence of strain H-3, which carries the sul1, sul2 and intI1 genes, resulted in an increase in sul1, followed by a subsequent decrease, while the levels of sul2 and intI1 continued to rise. This study is the first to report that Acinetobacter sp. strain H-3 can effectively remove SDZ at low temperatures. Furthermore, it provides a preliminary evaluation of the ecological risks linked to the dissemination of ARGs during the application of this strain, contributing valuable resources and theoretical insights for the bioremediation of antibiotic-polluted soil in cold areas.