Genotypic antimicrobial resistance assays for use on E. coli isolates and stool specimens

PLoS One. 2019 May 10;14(5):e0216747. doi: 10.1371/journal.pone.0216747. eCollection 2019.

Abstract

Antimicrobial resistance (AMR) is an emerging public health problem and methods for surveillance are needed. We designed 85 sequence-specific PCR reactions to detect 79 genes or mutations associated with resistance across 10 major antimicrobial classes, with a focus on E. coli. The 85 qPCR assays demonstrated >99.9% concordance with sequencing. We evaluated the correlation between genotypic resistance markers and phenotypic susceptibility results on 239 E. coli isolates. Both sensitivity and specificity exceeded 90% for ampicillin, ceftriaxone, cefepime, imipenem, ciprofloxacin, azithromycin, gentamicin, amikacin, trimethoprim/sulfamethoxazole, tetracycline, and chloramphenicol phenotypic susceptibility results. We then evaluated the assays on direct stool specimens and observed a sensitivity of 97% ± 5 but, as expected, a lower specificity of 75% ± 31 versus the genotype of the E. coli cultured from stool. Finally, the assays were incorporated into a convenient TaqMan Array Card (TAC) format. These assays may be useful for tracking AMR in E. coli isolates or directly in stool for targeted testing of the fecal antibiotic resistome.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Drug Resistance, Bacterial / genetics*
  • Escherichia coli / drug effects*
  • Escherichia coli / genetics*
  • Feces / microbiology*
  • Genotype*
  • Humans
  • Phenotype
  • Polymerase Chain Reaction
  • Sequence Analysis, DNA

Substances

  • Anti-Bacterial Agents