Molecular in-depth evaluations of invasive carbapenem-resistant Klebsiella pneumoniae isolates secondary to gastrointestinal colonization

Klebsiella pneumoniae represent a common invasive infection aetiological agent, whose potential carbapenem-resistance and hypermucoviscosity complicate the patient's management. Infection development often derives from gastrointestinal colonization; thus, it is fundamental to monitor asymptomatic K. pneumoniae colonization through surveillance protocols, especially for intensive care and immunocompromised patients. We described a six-month routine screening protocol from the Policlinico of Catania (Italy), while blood samples were collected from the same patients only in the case of a systemic infection suspicion. All the patients who had dissemination episodes were furtherly investigated through next generation sequencing, analysing both colonizing and disseminating strains. The study documented emerging invasive sequence types such as ST101, ST307, and ST395, mainly revealing NDM or KPC genes, along with siderophores and hyperproduction capsule markers as virulence factors. Most of the detected factors were related to a specific plasmid content, which was extremely varied and rich. In conclusion, active surveillance through sequencing is essential to enhance awareness about local epidemiology within high-risk multi-drug resistance areas. A random sequencing analysis on the most warning microorganisms could enhance STs awareness within specific settings, allowing better prevention control strategies on their eventual persistence or diffusion.