Successful Transition to Whole-Genome Sequencing and Bioinformatics to Identify Invasive Streptococcus spp. Drug Resistance, Alaska, USA

Abstract

The Centers for Disease Control and Prevention’s Arctic Investigations Program evaluated whole-genome sequencing (WGS) workflows and bioinformatics pipelines developed by the Centers’ Streptococcus Laboratory. We compared WGS-based antimicrobial drug resistance predictions with phenotypic testing for group B (n = 130) and group A (n = 217) Streptococcus and Streptococcus pneumoniae (n = 293). Isolates were collected in Alaska during January 2019-February 2021. We also included a historical phenotypically nonsusceptible subset. Concordances between phenotypic testing and WGS predictions were 99.9% (895/896) for group B Streptococcus, 100% (1,298/1,298) for group A Streptococcus, and 99.98% (3,516/3,517) for S. pneumoniae. Common resistance determinants were ermTR, ermB, and mef for macrolides, tetM for tetracyclines, and gyrA and parC for levofloxacin. S. pneumoniae trimethoprim/sulfamethoxazole nonsusceptibility was associated with folP gene insertions and folA mutations. In 2022, the Arctic Investigations Program transitioned Streptococcus spp. workflows to WGS, enabling more rapid monitoring and prevention of invasive disease.