Klebsiella pneumoniae blaNDM-1 carrying a class 1 integron causing a hospital outbreak in a Mexican attention center

Abstract

Introduction: Infections acquired in hospitals are the cause of high morbidity and mortality and with the emergence of resistant bacteria, the problem is greater. The aim of this work was to determine the genetic characteristics and timeline of Klebsiella pneumoniae bla_NDM-1 carrying a class 1 integron involved in an intrahospital outbreak.

Methodology: Investigation was made from the first detection of K. pneumoniae bla_NDM-1, strain “466”, and the last clone “423”. 16S rRNA gene analysis showed that 466 strain and clones were related to K. pneumoniae. Extended-spectrum β-lactamases (ESBL) was detected according to the Clinical and Laboratory Standards Institute (CLSI) and real time-PCR. Typing of K. pneumoniae bla_NDM-1 strains was carried by ERIC-PCR and sequencing the variable region of the integrons were performed.

Results: A cluster of six resistant isolates of K. pneumoniae bla_NDM-1 was detected in intensive care unit (ICU), internal medicine (IM) and orthopedics (OT). Timeline revealed that the first bacterial identification was in ICU and the last clone in OT service. The array genetic of variable region was “IntI/aadA5-drfA17/qacEΔ1-Sul1”.

Conclusions: The evidences highlight the importance of the epidemiological surveillance of Extended-spectrum β-lactamases (ESBL) strains, as well as the need for molecular epidemiological studies to identify the routes of transmission and the contamination sources within health personnel.