Using a commercial DiversiLab semiautomated repetitive sequence-based PCR typing technique for identification of Escherichia coli clone ST131 producing CTX-M-15

Abstract

A study was designed to evaluate the ability of the DiversiLab fingerprinting kit, a type of repetitive element PCR (rep-PCR), to identify Escherichia coli clone ST131 producing beta-lactamase CTX-M-15. A set of 53 nonduplicate isolates of extended-spectrum beta-lactamase-producing E. coli underwent rep-PCR, pulsed-field gel electrophoresis, and multilocus sequence typing. The DiversiLab system successfully identified E. coli clone ST131 producing CTX-M-15 and provides a simple standardized typing protocol for monitoring the spread of this clone.

FIG. 1.

PFGE patterns and dendrogram of CTX-M-15-producing E. coli isolates. The 15A, 15AR, and 15B isolates formed separate clones with >80% similar PFGE profiles. The 15AR isolates exhibited >60% similarity of profiles to 15A, which suggests that 15AR is related to 15A, while 15BR isolates exhibited >60% similarity of profiles to 15R, which suggests that 15BR is related to 15B.

FIG. 2.

Dendrogram analysis and virtual gel images of DiversiLab rep-PCR fingerprint analysis of ESBL-producing E. coli isolates. For the purpose of predicting different clones, the top match feature at >95% similarity was used (broken line). Clones 15A, 15AR, 15B, and 15BR were identified using PFGE, while ST131 was identified using MLST. MLST was performed on the CTX-M-15-producing isolates. Sample ID, sample identification.