Whole-genome sequencing reveals clonal expansion of multiresistant Staphylococcus haemolyticus in European hospitals
Abstract
Objectives Staphylococcus haemolyticus is an emerging cause of nosocomial infections, primarily affecting immunocompromised patients. A comparative genomic analysis was performed on clinical S. haemolyticus isolates to investigate their genetic relationship and explore the coding sequences with respect to antimicrobial resistance determinants and putative hospital adaptation. Methods Whole-genome sequencing was performed on 134 isolates of S. haemolyticus from geographically diverse origins (Belgium, 2; Germany, 10; Japan, 13; Norway, 54; Spain, 2; Switzerland, 43; UK, 9; USA, 1). Each genome was individually assembled. Protein coding sequences (CDSs) were predicted and homologous genes were categorized into three types: Type I, core genes, homologues present in all strains; Type II, unique core genes, homologues shared by only a subgroup of strains; and Type III, unique genes, strain-specific CDSs. The phylogenetic relationship between the isolates was built from variable sites in the form of single nucleotide polymorphisms (SNPs) in the core genome and used to construct a maximum likelihood phylogeny. Results SNPs in the genome core regions divided the isolates into one major group of 126 isolates and one minor group of isolates with highly diverse genomes. The major group was further subdivided into seven clades (A–G), of which four (A–D) encompassed isolates only from Europe. Antimicrobial multiresistance was observed in 77.7% of the collection. High levels of homologous recombination were detected in genes involved in adherence, staphylococcal host adaptation and bacterial cell communication. Conclusions The presence of several successful and highly resistant clones underlines the adaptive potential of this opportunistic pathogen.
Citation
Cavanagh , J P , Hjerde , E , Holden , M T G , Kahlke , T , Klingenberg , C , Flægstad , T , Parkhill , J , Bentley , S D & Sollid , J U E 2014 , ' Whole-genome sequencing reveals clonal expansion of multiresistant Staphylococcus haemolyticus in European hospitals ' , Journal of Antimicrobial Chemotherapy , vol. 69 , no. 11 , pp. 2920-2927 . https://doi.org/10.1093/jac/dku271
Publication
Journal of Antimicrobial Chemotherapy
Status
Peer reviewed
ISSN
0305-7453Type
Journal article
Rights
© The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
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