Carbapenem-Resistant Acinetobacter baumannii (CRAB) Outbreak Control using Microbial Genomics – a Case Study

Krispin Hajkowicz1

1 School of Clinical Medicine, University of Queensland,


An outbreak of carbapenem-resistant Acinetobacter baumannii (CRAB) occurred in a hospital burns unit, resulting in eight patient colonisations (detected on rectal swab screening) and one patient with an external ear infection requiring partial surgical removal of the pinna. Rapid whole genome sequencing (WGS) using Illumina NextSeq500 demonstrated that all isolates were sequence type 1050 (ST1050). Conventional culture methods were unsuccessful in detecting an environmental reservoir of the CRAB type. A metagenomic approach was employed, demonstrating the presence of the same ST1050 CRAB strain in the pipes draining one of the three baths used for patients with severe burns. Enhanced outbreak management and infection control practices, limitation of patient movement in and out of the unit and specific enhanced cleaning and removal and replacement of the contaminated environmental source was used. Rapid dissemination of the results of genomic investigations optimised the timely decision making of the outbreak management team, detected the source of the environmental reservoir and excluded other possible routes of transmission. Results were presented to the hospital infection control team using a novel healthcare outbreak communication tool, HAIviz. Use of WGS should become routine practice in the response to healthcare-associated outbreaks of multi-resistant organisms.

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