Vendrik, Karuna E Wde Haan, AngelaWitteveen, SandraHendrickx, Antoni P ALandman, FabianNotermans, Daan WBijkerk, PaulSchoffelen, Annelot Fde Greeff, Sabine CWielders, Cornelia C HGoeman, Jelle JKuijper, Ed JSchouls, Leo M2022-07-312022-07-312022-05-203560743210.1038/s43856-022-00115-6http://hdl.handle.net/10029/625958A six-month prospective matched case-control study was performed in which 22 Dutch laboratories with 32 associated hospitals participated. Laboratories were invited to send a maximum of five colistin-resistant Escherichia coli or Klebsiella pneumoniae (COLR-EK) isolates and five colistin-susceptible isolates (COLS-EK) to the reference laboratory, matched for patient location, material of origin and bacterial species. Epidemiological/clinical data were collected and included in the analysis. Characteristics of COLR-EK/COLS-EK isolates were compared using logistic regression with correction for variables used for matching. Forty-six ColR-EK/ColS-EK pairs were analysed by next-generation sequencing (NGS) for whole-genome multi-locus sequence typing and identification of resistance genes, including mcr genes. To identify chromosomal mutations potentially leading to colistin resistance, NGS reads were mapped against gene sequences of pmrAB, phoPQ, mgrB and crrB.en© The Author(s) 2022.Antimicrobial resistanceEpidemiologyInfectious-disease epidemiologyArticle2730-664XCommun Med 2022;2:55