Journal Article

Anatomy of an extensively drug-resistant Klebsiella pneumoniae outbreak in Tuscany, Italy

Mills, Emma G., Martin, Melissa J., Harless, Casey, Cusi, Maria Grazia, Hall, Lindsey R., Russo, Thomas A., Hübner, Nils-Olaf, Lebreton, Francois, Schaufler, Katharina, Tordini, Giacinta, Maybank, Rosslyn, Sannio, Filomena, Becker, Karsten, Valassina, Marcello, MacDonald, Ulrike, Stam, Jason, Docquier, Jean-Denis, Bennett, Jason W., Jones, Brendan T., Corey, Brendan W., Cresti, Stefania, Kwak, Yoon, McGann, Patrick T.

2021

Overview

A protracted outbreak of New Delhi metallo-β-lactamase (NDM)– producing carbapenem-resistant Klebsiella pneumoniae started in Tuscany, Italy, in November 2018 and continued in 2020 and through 2021. To understand the regional emergence and transmission dynamics over time, we collected and sequenced the genomes of 117 extensively drug-resistant, NDM-producing K. pneumoniae isolates cultured over a 20-mo period from 76 patients at several healthcare facilities in southeast Tuscany. All isolates belonged to high-risk clone ST-147 and were typically nonsusceptible to all first-line antibiotics. Albeit sporadic, resistances to colistin, tigecycline, and fosfomycin were also observed as a result of repeated, independent mutations. Genomic analysis revealed that ST-147 isolates circulating in Tuscany were monophyletic and highly genetically related (including a network of 42 patients from the same hospital and sharing nearly identical isolates), and shared a recent ancestor with clinical isolates from the Middle East. While the bla NDM-1 gene was carried by an IncFIB-type plasmid, our investigations revealed that the ST-147 lineage from Italy also acquired a hybrid IncFIB/IncHIB–type plasmid carrying the 16S methyltransferase armA gene as well as key virulence biomarkers often found in hypervirulent isolates. This plasmid shared extensive homologies with mosaic plasmids circulating globally including from ST-11 and ST-307 convergent lineages. Phenotypically, the carriage of this hybrid plasmid resulted in increased siderophore production but did not confer virulence to the level of an archetypical, hypervirulent K. pneumoniae in a subcutaneous model of infection with immunocompetent CD1 mice. Our findings highlight the importance of performing genomic surveillance to identify emerging threats.

• Publisher: National Academy of Sciences
• Subject: Animals / Anti-Bacterial Agents / Antibiotics / Bacterial Proteins - genetics / beta-Lactamases - genetics / Biological Sciences / Biomarkers / carbapenemase / Carbapenems / Clinical isolates / Colistin / Computational Biology - methods / Cross Infection - epidemiology / Disease Outbreaks / Drug resistance / Drug Resistance, Multiple, Bacterial - genetics / Fosfomycin / Genomes / Genomic analysis / Health care facilities / Homology / Humans / Italy - epidemiology / Kaplan-Meier Estimate / Klebsiella / Klebsiella Infections - epidemiology / Klebsiella penumoniae / Klebsiella pneumoniae / Klebsiella pneumoniae - genetics / Life sciences / Likelihood Functions / Metallo-β-lactamase / Metallography / Methyltransferase / Mice / Microbial Sensitivity Tests / Microbiologie / Microbiology / Mutation / NDM-1 metallo-beta-lactamase / Outbreaks / Patients / Pharmaceutical Preparations / Plasmids / Polymorphism, Single Nucleotide / Sciences du vivant / Tigecycline / Virulence / whole genome sequencing / β Lactamase