Investigation of a possible outbreak of carbapenem-resistant Acinetobacter baumannii in Odense, Denmark using PFGE, MLST and whole-genome-based SNPs. (19th March 2015)

• Record Type: Journal Article
• Authors: Hammerum, Anette M.; Hansen, Frank; Skov, Marianne N.; Stegger, Marc; Andersen, Paal S.; Holm, Anette; Jakobsen, Lotte; Justesen, Ulrik S.
• Is Part Of: Journal of antimicrobial chemotherapy. Volume 70:Number 7(2015:Jul.)
• Page Start: 1965
• Page End: 1968
• Publication Date: 2015-03-19
• Subjects: antimicrobial resistance -- antimicrobial resistance epidemiology -- carbapenems; Anti-infective agents -- Periodicals; Chemotherapy -- Periodicals; 615.58
• DOI: 10.1093/jac/dkv072
• Languages: English
• ISSNs: 0305-7453

Abstract

Abstract : Whole-genome sequencing techniques helped confirm an outbreak due to three different strains of resistant Acinetobacter baumannii in Odense, Denmark, so might prove more useful than alternative approaches for tracing the spread of clones nationally and internationally. Abstract: Objectives: The objectives were to study a possible outbreak of carbapenem-resistant Acinetobacter baumannii by comparing three different typing methods (PFGE, MLST and whole-genome SNPs) and to compare the resistance gene profiles of the isolates. Methods: From December 2012 to October 2013, eight carbapenem-resistant A. baumannii were detected at Odense University Hospital, Odense, Denmark. These isolates were typed by PFGE, with ApaI and SmaI, respectively, and subjected to WGS. The WGS data were used for in silico extraction of MLST types using two different schemes, resistance genes and SNPs, to which 31 publicly available A. baumannii genomes were added. Results: Using ApaI, the eight isolates had four different PFGE profiles, which were further differentiated using SmaI, separating one of the profiles into two distinct PFGE types. Five ST2 (Pasteur MLST) OXA-23-producing isolates, two ST1 OXA-72-producing isolates and one ST158 OXA-23-producing isolate were detected. The five ST2 isolates were subdivided into ST195, ST208 and ST218 using the Oxford MLST scheme. The phylogenetic analysis based on the core genome showed that six of the eight Danish A. baumannii isolates were located in three distinct clusters. The two remaining isolates did not cluster with other Danish or international isolates included in the study. Isolates that clustered using PFGE, Oxford MLST and phylogenetic analysis also shared similar resistance gene profiles. Conclusions: The SNP profile, Oxford MLST, PFGE and resistance gene profiles clearly indicated spread of three different A. baumannii strains.