Polymyxin antibiotics are used as last-resort therapies to treat infections caused by multidrug-resistant Gram-negative bacteria. The plasmid-mediated colistin resistance determinant MCR-1 has been identified in Enterobacteriaceae in China. We did this study to investigate the prevalence of the mcr-1 gene in clinical isolates from patients with bloodstream infections in China.Clinical isolates of Escherichia coli and Klebsiella pneumoniae were collected from patients with bloodstream infections at 28 hospitals in China, then screened for colistin resistance by broth microdilution and for the presence of the mcr-1 gene by PCR amplification. We subjected mcr-1-positive isolates to genotyping, susceptibility testing, and clinical data analysis. We established the genetic location of mcr-1 with Southern blot hybridisation, and we analysed plasmids containing mcr-1 with filter mating, electroporation, and DNA sequencing.2066 isolates, consisting of 1495 E coli isolates and 571 K pneumoniae isolates were collected. Of the 1495 E coli isolates, 20 (1%) were mcr-1-positive, whereas we detected only one (<1%) mcr-1-positive isolate among the 571 k pneumoniae isolates. all e coli and isolates were resistant to colistin, with minimum inhibitory concentrations values in range of 4-32 mg/l, except for one that had a concentration less than or equal 0·06 mg/l. 21 susceptible tigecycline 20 (95%) carbapenem ß-lactamase inhibitor combination piperacillin tazobactam. also produced ndm-5, which confers resistance beta-lactam antibiotics. clonally diverse carried mcr-1 on two types plasmids, 33 kb incx4 plasmid 61 inc12 plasmid. 30 day mortality patients bloodstream infections caused by was zero.mcr-1-positive from rare, sporadic, remained many antimicrobial agents. coli, rather pneumoniae, main host gene. further studies are needed clarify clinical impact this novel gene.national natural science foundation china. copyright © 2017 elsevier ltd. rights reserved.
Journal: The Lancet. Infectious diseases
DOI: 10.1016/S1473-3099(16)30528-X
Year: 2017