Agrobacterium spp. nosocomial outbreak assessment using rapid MALDI-TOF MS based typing, confirmed by whole genome sequencing.

Casanova, Carlo; Lo Priore, Elia; Egli, Adrian; Seth-Smith, Helena M B; Räber, Lorenz; Ott, Daniel; Pflüger, Valentin; Droz, Sara Christine; Marschall, Jonas; Sommerstein, Rami (2019). Agrobacterium spp. nosocomial outbreak assessment using rapid MALDI-TOF MS based typing, confirmed by whole genome sequencing. Antimicrobial resistance and infection control, 8, p. 171. BioMed Central 10.1186/s13756-019-0619-y

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A number of episodes of nosocomial Agrobacterium spp. bacteremia (two cases per year) were observed at Bern University Hospital, Switzerland, from 2015 to 2017. This triggered an outbreak investigation.


Cases of Agrobacterium spp. bacteremias that occurred between August 2011 and February 2017 were investigated employing line lists, environmental sampling, rapid protein- (MALDI-TOF MS), and genome-based typing (pulsed field gel electrophoresis and whole genome sequencing) of the clinical isolates.


We describe a total of eight bacteremia episodes due to A. radiobacter (n = 2), Agrobacterium genomovar G3 (n = 5) and A. pusense (n = 1). Two tight clusters were observed by WGS typing, representing the two A. radiobacter isolates (cluster I, isolated in 2015) and four of the Agrobacterium genomovar G3 isolates (cluster II, isolated in 2016 and 2017), suggesting two different point sources. The epidemiological investigations revealed two computer tomography (CT) rooms as common patient locations, which correlated with the two outbreak clusters. MALDI-TOF MS permitted faster evaluation of strain relatedness than DNA-based methods. High resolution WGS-based typing confirmed the MALDI-TOF MS clustering.


We report clinical and epidemiological characteristics of two outbreak clusters with Agrobacterium. spp. bacteremia likely acquired during CT contrast medium injection and highlight the use of MALDI-TOF MS as a rapid tool to assess relatedness of rare gram-negative pathogens in an outbreak investigation.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Infectiology
04 Faculty of Medicine > Department of Cardiovascular Disorders (DHGE) > Clinic of Cardiology
04 Faculty of Medicine > Department of Radiology, Neuroradiology and Nuclear Medicine (DRNN) > Institute of Diagnostic, Interventional and Paediatric Radiology
04 Faculty of Medicine > Service Sector > Institute for Infectious Diseases > General Bacteriology

UniBE Contributor:

Casanova, Carlo, Lo Priore, Elia Francesco, Räber, Lorenz, Ott, Daniel, Droz, Sara Christine, Marschall, Jonas, Sommerstein, Rami


600 Technology > 610 Medicine & health
600 Technology > 630 Agriculture




BioMed Central




Annelies Luginbühl

Date Deposited:

20 Nov 2019 14:14

Last Modified:

05 Dec 2022 15:32

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

Agrobacterium MALDI-TOF MS Nosocomial outbreak Rhizobium Whole genome sequencing




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