Genome sequences of two clinical Escherichia coli isolates harboring the novel colistin-resistance gene variants mcr - 1.26 and mcr - 1.27

• Published in: Gut pathogens Vol. 12; no. 1; pp. 40 - 7
• Main Authors: Neumann, Bernd, Rackwitz, Wiebke, Hunfeld, Klaus-Peter, Fuchs, Stephan, Werner, Guido, Pfeifer, Yvonne
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 03.09.2020; BioMed Central; BMC
• Subjects: Algorithms; Amino acid sequence; Antibiotics; Clinical isolates; Colistin; Colistin-resistance; Deoxyribonucleic acid; DNA; DNA sequencing; Drug resistance; E coli; Escherichia coli; Experiments; Genes; Genetic aspects; Genome Report; Genomes; Genomics; Genotyping; Gram-negative bacteria; Health aspects; Hospital patients; IncX4; mcr-1; Microbial drug resistance; Multidrug resistance; Mutation; Nucleotide sequence; Patients; Pipelines; Plasmids; Sodium azide; Tetracyclines; Veterinary medicine; Virulence; Germany; IncX4; Colistin-resistance; Escherichia coli; mcr-1
• ISSN: 1757-4749; 1757-4749
• DOI: 10.1186/s13099-020-00375-4

Colistin is still a widely used antibiotic in veterinary medicine although it is a last-line treatment option for hospitalized patients with infections caused by multidrug-resistant Gram-negative bacteria. Colistin resistance has gained additional importance since the recent emergence of mobile colistin resistance ( ) genes. In the scope of a study on colistin resistance in clinical isolates from human patients in Germany we characterized the - gene variants. Our PCR-based screening for -carrying from German patients revealed the presence of - - genes in 60 isolates. Subsequent whole-genome sequence-based analyses detected one non-synonymous mutation in the - gene for two isolates. The mutations were verified by Sanger sequencing and resulted in amino acid changes Met1Thr (isolate 803-18) and Tyr9Cys (isolate 844-18). Genotyping revealed no relationship between the isolates. The two clinical isolates were assigned to sequence types ST155 (isolate 803-18) and ST69 (isolate 844-18). Both - variants were found to be located on IncX4 plasmids of 33 kb size; these plasmids were successfully conjugated into sodium azide resistant J53 Azi in a broth mating experiment. Here we present the draft sequences of isolate 803-18 carrying the novel variant - and isolate 844-14 carrying the novel variant - . The results highlight the increasing issue of transferable colistin resistance.