Nosocomial outbreak due to a novel Sequence Type of carbapenem resistant Acinetobacter seifertii

Abstract

BackgroundAcinetobacter seifertii, a member of A.baumannii-calcoaceticus complex, can be considered a pathogen of concern due to the presence of resistance genes. The aim of the study was to describe an outbreak of carbapenem-resistant A. seifertii (CRAS) among neonates admitted to the Neonatal Intensive Care Unit (NICU) at a tertiary care hospital. MethodsAll patients with CRAS diagnosed and admitted to the NICU from June 2023 to October 2023 were included. The presence of carbapenemase genes (blaIMP, blaVIM, blaNDM, blaKPC, blaGES, blaOXA-48-like and blaOXA-23) was investigated by qPCR. Whole Genome Sequencing (WGS) was performed by MiSeq (Illumina) and MinION (Nanopore) platforms. FTIR (IR Biotyper®) was applied for microbial strain typing. ResultsEleven patients were affected and a set of measures were implemented at NICU to reduce the risk of transmission. The isolates exhibited identical resistance patterns, additionally, all isolates presented the blaNDM-1 gene and were grouped in the same cluster by IR Biotyper. The WGS revealed that the isolates belonged to a novel ST assigned as ST2712, and the blaNDM-1 was carried by the same plasmid type. DiscussionOur study has identified a novel strain of A. seifertii carrying blaNDM-1 responsible for the outbreak, indicating its emergence in the institution. ConclusionThis is the first report of carbapenem resistant A. seifertii ST2712. The use of WGS for genomic surveillance allowed understanding the dissemination of CRAB which is crucial in outbreak scenarios.