AUTHOR=Zheng Beiwen , Huang Chen , Xu Hao , Guo Lihua , Zhang Jing , Wang Xin , Jiang Xiawei , Yu Xiao , Jin Linfeng , Li Xuewen , Feng Youjun , Xiao Yonghong , Li Lanjuan TITLE=Occurrence and Genomic Characterization of ESBL-Producing, MCR-1-Harboring Escherichia coli in Farming Soil JOURNAL=Frontiers in Microbiology VOLUME=8 YEAR=2017 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.02510 DOI=10.3389/fmicb.2017.02510 ISSN=1664-302X ABSTRACT=

The emergence and spread of the mobile colistin resistance gene (mcr-1) has become a major global public health concern. So far, this gene has been widely detected in food animals, pets, food, and humans. However, there is little information on the contamination of mcr-1-containing bacteria in farming soils. In August 2016, a survey of ESBL-producing Escherichia coli isolated from farming soils was conducted in Shandong Province, China. We observed colistin resistance in 12 of 53 (22.6%) ESBL-producing Enterobacteriaceae isolates from farming soil. Six mcr-1-positive E. coli strains originating from a livestock-intensive area were found. The isolates belonged to four different STs (ST2060, ST3014, ST6756, and ST1560) and harbored extensive additional resistance genes. An E. coli with blaNDM-1 was also detected in a soil sample from the same area. Comparative whole genome sequencing and S1-PFGE analysis indicated that mcr-1 was chromosomally encoded in four isolates and located on IncHI2 plasmids in two isolates. To our knowledge, we report the first isolation of mcr-1 in ESBL-producing E. coli from farming soils. This work highlights the importance of active surveillance of colistin-resistant organisms in soil. Moreover, investigations addressing the influence of animal manure application on the transmission of mcr-1-producing bacteria are also warranted.