León-Sampedro R, de la Fuente J, Díaz-Agero C,... San Millán Á. Pervasive transmission of a carbapenem resistance plasmid in the gut microbe of hospitalized patients

Nature Microbiology. 2021

"Our results suggest that the horizontal spread of pOXA-48 in the gut microbiota is probably the norm in colonized patients" - Dr. Álvaro San Millán -


Infections caused by carbapenemase-producing enterobacteria (CPE) are a major concern in clinical settings worldwide. Two fundamentally different processes shape the epidemiology of CPE in hospitals: the dissemination of CPE clones from patient to patient (between-patient transfer), and the transfer of carbapenemase-encoding plasmids between enterobacteria in the gut microbiota of individual patients (within-patient transfer). The relative contribution of each process to the overall dissemination of carbapenem resistance in hospitals remains poorly understood. Here, we used mechanistic models combining epidemiological data from more than 9,000 patients with whole genome sequence information from 250 enterobacteria clones to characterise the dissemination routes of a pOXA-48-like carbapenemase-encoding plasmid in a hospital setting over a two-year period. Our results revealed frequent between-patient transmission of high-risk pOXA-48-carrying clones, mostly of Klebsiella pneumoniae and sporadically Escherichia coli. The results also identified pOXA-48 dissemination hotspots within the hospital, such as specific wards and individual rooms within wards. Using high-resolution plasmid sequence analysis, we uncovered the pervasive within-patient transfer of pOXA-48, suggesting that horizontal plasmid transfer occurs in the gut of virtually every colonised patient. The complex and multifaceted epidemiological scenario exposed by this study provides insights for the development of intervention strategies to control the in-hospital spread of CPE.

Why do you highlight this publication?

This study characterizes, for the first time, the relative contribution of between-patient and within-patient plasmid transfer in the epidemiology of a carbapenem resistance plasmid. Our results will help to develop improved intervention strategies to control the spread of carbapenem resistance in hospitals.

Dr. Álvaro San Millán

Centro Nacional Biotecnología (CNB-CSIC)


Culture plate with different bacterial strains

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