title: Prediction of Staphylococcus aureus antimicrobial resistance by whole-genome sequencing.
abstract: Whole-genome sequencing (WGS) could potentially provide a single platform for extracting all the information required to predict an organism's phenotype. However, its ability to provide accurate predictions has not yet been demonstrated in large independent studies of specific organisms. In this study, we aimed to develop a genotypic prediction method for antimicrobial susceptibilities. The whole genomes of 501 unrelated Staphylococcus aureus isolates were sequenced, and the assembled genomes were interrogated using BLASTn for a panel of known resistance determinants (chromosomal mutations and genes carried on plasmids). Results were compared with phenotypic susceptibility testing for 12 commonly used antimicrobial agents (penicillin, methicillin, erythromycin, clindamycin, tetracycline, ciprofloxacin, vancomycin, trimethoprim, gentamicin, fusidic acid, rifampin, and mupirocin) performed by the routine clinical laboratory. We investigated discrepancies by repeat susceptibility testing and manual inspection of the sequences and used this information to optimize the resistance determinant panel and BLASTn algorithm. We then tested performance of the optimized tool in an independent validation set of 491 unrelated isolates, with phenotypic results obtained in duplicate by automated broth dilution (BD Phoenix) and disc diffusion. In the validation set, the overall sensitivity and specificity of the genomic prediction method were 0.97 (95% confidence interval [95% CI], 0.95 to 0.98) and 0.99 (95% CI, 0.99 to 1), respectively, compared to standard susceptibility testing methods. The very major error rate was 0.5%, and the major error rate was 0.7%. WGS was as sensitive and specific as routine antimicrobial susceptibility testing methods. WGS is a promising alternative to culture methods for resistance prediction in S. aureus and ultimately other major bacterial pathogens.
authors: NIHR Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, United Kingdom.
authors: N C
authors: NC
authors: Gordon
authors: J R
authors: JR
authors: Price
authors: K
authors: K
authors: Cole
authors: R
authors: R
authors: Everitt
authors: M
authors: M
authors: Morgan
authors: J
authors: J
authors: Finney
authors: A M
authors: AM
authors: Kearns
authors: B
authors: B
authors: Pichon
authors: B
authors: B
authors: Young
authors: D J
authors: DJ
authors: Wilson
authors: M J
authors: MJ
authors: Llewelyn
authors: J
authors: J
authors: Paul
authors: T E A
authors: TE
authors: Peto
authors: D W
authors: DW
authors: Crook
authors: A S
authors: AS
authors: Walker
authors: T
authors: T
authors: Golubchik
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D019295:Computational Biology / Q000379:methods*; D024881:Drug Resistance, Bacterial; D016680:Genome, Bacterial; D006801:Humans; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000379:methods*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents