AUTHOR=Fan Rong , Li Chuchu , Duan Ran , Qin Shuai , Liang Junrong , Xiao Meng , Lv Dongyue , Jing Huaiqi , Wang Xin 

TITLE=Retrospective Screening and Analysis of mcr-1 and blaNDM in Gram-Negative Bacteria in China, 2010–2019

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00121

DOI=10.3389/fmicb.2020.00121

ISSN=1664-302X

ABSTRACT=<p>Currently, Gram-negative bacteria have developed multidrug and broad-spectrum drug resistance, and the numbers of species and strains carrying <italic>mcr</italic> or <italic>bla</italic><sub>NDM</sub> genes are increasing. In this study, <italic>mcr-1</italic> and <italic>bla</italic><sub>NDM</sub> distribution of 12,858 Gram-negative bacteria isolated from wildlife, patients, livestock, poultry and environment in 14 provinces of China from 2010 to 2019 and the antibiotics resistance in regard to polymyxins (polymyxin B and colistin) and carbapenems of positive strains were investigated. A total of 70 strains of 10 species carried the <italic>mcr-1</italic> gene, positive rates of patients, livestock and poultry, and environmental strains were 0.62% (36/5,828), 4.07% (29/712), 5.43% (5/92), respectively. Six strains of 3 species carrying the <italic>bla</italic><sub>NDM</sub> gene all came from patients 0.10% (6/5,828). Two new <italic>mcr-1</italic> gene variants (GenBank: MK965883, MK965884) were identified, one of which contains premature stop codon. The drug susceptibility results showed that all <italic>mcr-1</italic> carriers were sensitive to carbapenems, among which, 66 strains were resistant and 4 were sensitive to polymyxins. The strains with the <italic>bla</italic><sub>NDM</sub> gene had different degrees of resistance to carbapenems and were sensitive to polymyxins. The findings that species carrying <italic>mcr-1</italic> or <italic>bla</italic><sub>NDM</sub> genes were limited and mostly normal flora of opportunistic or low pathogenic organisms indicated that transfer of <italic>mcr-1</italic> and <italic>bla</italic><sub>NDM</sub> genes between bacteria was relatively limited in China. The none detection among wildlife compared with other sources supports the speculation that the emergence of and increase in polymyxins and carbapenem-resistant strains was mainly related to the selective pressure of antibiotics.</p>