Molecular characterization of CTX‐M‐15‐producing clinical isolates of Escherichia coli reveals the spread of multidrug‐resistant ST131 (O25:H4) and ST964 (O102:H6) strains in Norway |
| |
Authors: | UMAER NASEER BJ
RG HALDORSEN STLE TOFTELAND KRISTIN HEGSTAD FLEMMING SCHEUTZ GUNNAR SKOV SIMONSEN ARNFINN SUNDSFJORD |
| |
Institution: | 1. Reference Centre for Detection of Antimicrobial Resistance (K‐res), Department of Microbiology and Infection Control, University Hospital of North‐Norway, Troms?;2. Department of Microbiology, S?rlandet Hospital, Kristiansand;3. Department of Microbiology and Virology, University of Troms?, Troms?, Norway;4. The International Escherichia and Klebsiella Centre (WHO), Statens Serum Institut, Copenhagen, Denmark;5. Division of Infection Control, Norwegian Institute of Public Health, Oslo, Norway |
| |
Abstract: | Nationwide, CTX‐M‐producing clinical Escherichia coli isolates from the Norwegian ESBL study in 2003 (n=45) were characterized on strain and plasmid levels. BlaCTX‐M allele typing, characterization of the genetic environment, phylogenetic groups, pulsed field gel electrophoresis (PFGE), serotyping and multilocus sequence typing were performed. Plasmid analysis included S1‐nuclease‐PFGE, polymerase chain reaction‐based replicon typing, plasmid transfer and multidrug resistance profiling. BlaCTX‐M‐15 (n=23; 51%) and blaCTX‐M‐14 (n=11; 24%) were the major alleles of which 18 (78%) and 6 (55%), respectively, were linked to ISEcp1. Thirty‐two isolates were of phylogenetic groups B2 and D. Isolates were of 29 different XbaI‐PFGE‐types including six regional clusters. Twenty‐three different O:H serotypes were found, dominated by O25:H4 (n=9, 20%) and O102:H6 (n=9, 20%). Nineteen different STs were identified, where ST131 (n=9, 20%) and ST964 (n=7, 16%) were dominant. BlaCTX‐M was found on ≥100 kb plasmids (39/45) of 10 different replicons dominated by IncFII (n=39, 87%), FIB (n=20, 44%) and FIA (n=19, 42%). Thirty‐nine isolates (87%) displayed co‐resistance to other classes of antibiotics. A transferable CTX‐M phenotype was observed in 9/14 isolates. This study reveals that the majority of CTX‐M‐15‐expressing strains in Norway are part of the global spread of multidrug‐resistant ST131 and ST‐complex 405, associated with ISEcp1 on transferrable IncFII plasmids. |
| |
Keywords: | ESBL CTX‐M‐15 MDR ST131 PBRT |
|
|