Novel Multiplex PCR Enables Rapid Screening for Multidrug-Resistant E. coli ST648
Researchers developed and validated a multiplex PCR assay exploiting SNPs in icd and gyrB alleles to rapidly identify E. coli sequence type 648, an emerging multidrug-resistant lineage within phylogroup F. The assay achieved 100% sensitivity and specificity across 212 strains and works with simple boiled lysates, making it accessible to any diagnostic PCR-equipped laboratory for AMR surveillance.
The original study
Rapid and Specific Detection of the Escherichia coli Sequence Type 648 Complex within Phylogroup F.
- Authors
- Johnson JR, Johnston BD, Gordon DM
- Journal
- Journal of clinical microbiology
- Type
- Journal Article, Validation Study
- PMID
- 28100599
Original abstract
The Escherichia coli sequence type 648 complex (STc648) is an emerging lineage within phylogroup F-formerly included within phylogroup D-that is associated with multidrug resistance. Here, we designed and validated a novel multiplex PCR-based assay for STc648 that took advantage of (i) four distinctive single-nucleotide polymorphisms in icd allele 96 and gyrB allele 87, two of the multilocus sequence typing alleles that define ST648; and (ii) the typical absence within STc648 of uidA, an E. coli-specific gene encoding β-glucuronidase. Within a diverse 212-strain validation set that included 109 STs other than STc648, from phylogroups A, B1, B2, C, D, E, and F, the assay exhibited 100% sensitivity (95% confidence interval [CI], 82% to 100%) and specificity (95% CI, 98% to 100%). It functioned similarly well in two distant laboratories that used boiled lysates or DNAzol-purified DNA as the template DNA. Thus, this novel multiplex PCR-based assay should enable any laboratory equipped for diagnostic PCR to rapidly, accurately, and economically screen E. coli isolates for membership in STc648.