Combination of amplified rDNA restriction analysis and high-throughput sequencing revealed the negative effect of colistin sulfate on the diversity of soil microorganisms

Colistin sulfate is widely used in both human and veterinary medicine. However, its effect on the microbial ecologyis unknown. In this study, we determined the effect of colistin sulfate on the diversity of soil microorganisms by amplified rDNA restriction analysis (ARDRA) and high-throughput sequencing.ARDRAshowed that the diversity of DNA from soil microorganisms was reduced after soil was treated with colistin sulfate, with the most dramatic reductionobserved after 35 days of treatment. High-throughput sequencing showed that the Chao1 and abundance-based coverage estimators (ACE) were reduced in the soils treated with colistin sulfate for 35 dayscompared to those treated with colistin sulfate for 7 days. Furthermore, Chao1 and ACE tended to be lower when higher concentration of colistin sulfate was used, suggesting that the microbial abundance is reduced by colistin sulfate in a dose-dependent manner. Shannon index showed that the diversity of soil microorganism was reduced upon treatment with colistin sulfate compared to the untreated control group. Following 7 days of treatment, Bacillus, Clostridiumand Sphingomonas were sensitive to all the concentration of colistin sulfate used in this study. Following 35 days of treatment, the abundance of Choroplast, Haliangium, Pseudomonas, Lactococcus, and Clostridium was significantly decreased. Our results demonstrated that colistin sulfate especially at high concentration (≥5 mg/kg) could alter the population structure of microorganisms and consequently the microbial community function in soil.