OUP accepted manuscript

• DOI: 10.1093/jac/dky092
• Publication Date: 2018-03-21T12:08:18Z
• Authors: Jian Liu; Yun Li; Lanqing Cui; Yingbo Shen; Yuan Lv; Xiang-Jun Liu; Yang Wang; Feng Xue; L Wang
• Keywords: Male; 0301 basic medicine; China; Colistin; Escherichia coli Proteins; Microbial Sensitivity Tests; Anti-Bacterial Agents; Bacterial Typing Techniques; Klebsiella Infections; 3. Good health; Klebsiella pneumoniae; 03 medical and health sciences; Bacterial Proteins; Drug Resistance, Multiple, Bacterial; Escherichia coli; Humans; Female; Escherichia coli Infections; Phylogeny; Multilocus Sequence Typing; Retrospective Studies

To evaluate the prevalence of clinical mcr-1-positive Escherichia coli and Klebsiella pneumoniae and characterize the antimicrobial resistance profiles of mcr-1-positive E. coli and mcr-1-negative E. coli in China.A total of 6264 clinical E. coli (n = 3854) and K. pneumoniae (n = 2410) were collected from hospitalized patients from 18 to 20 hospitals as part of the China Antimicrobial Resistance Surveillance Trial (CARST) between January 2007 and June 2016. PCR was used to screen for the mcr-1 gene among all isolates. Antibiotic susceptibility testing was performed using the broth microdilution method. mcr-1-positive pathogens were then characterized by MLST and minimum spanning tree analysis using the BURST algorithm for related STs.We examined 39 (0.62%) clinical isolates of mcr-1-positive E. coli and K. pneumoniae over a 10 year period. Resistance to antimicrobial agents was significantly more severe in mcr-1-positive isolates than mcr-1-negative isolates, particularly piperacillin (P = 0.008), amikacin (P < 0.0001), nitrofurantoin (P < 0.004) and fosfomycin (P < 0.0001). Among mcr-1-carrying isolates, ESBL production was as high as 84.6% (33 of 39) and 92.3% (36 of 39) of them displayed an MDR phenotype. STs suggested ubiquitous dissemination of mcr-1-carrying pathogens.mcr-1-carrying E. coli and K. pneumoniae displayed a lower prevalence and abundant phylogenetic diversity in mainland China. mcr-1-positive E. coli showed significant differences in antimicrobial resistance profiles compared with mcr-1-negative E. coli strains, suggesting physicians may consider prescribing different antibiotics when faced with infections caused by mcr-1-positive pathogens.