Many congratulations to Adriana Chiarelli from the Ecology and Evolution of Antibiotics Resistance Unit brilliantly defended her PhD Thesis (Sorbonne Université) entitled ” Heterogenous carbapenem resistance among carbapenemase-producing Klebsielle pneumonia” on Monday, June 28th.
Abstract of the thesis:
Carbapenemase-producing K. pneumoniae (CPKp) represent a global threat, with significant mortality rates. Carbapenem heteroresistance (HR) is frequent among CPKp, as observed by the presence of colonies within the drug inhibition halo. Despite its clinical importance, mechanisms of HR in CPKp are unknown. My PhD project aimed at elucidating the bases of HR among CPKp clinical isolates. My results suggest that HR is prevalent among K. pneumoniae producing the KPC carbapenemase (KPC-Kp) and associated with heterogeneous survival to high concentrations of imipenem at single colony level, as assessed by using the ScanLag setup. Whole genome sequencing and phenotyping of surviving colonies revealed the complexity of HR in KPC-Kp, which arises from: tolerance and persistence, as deduced by the delayed and heterogeneous colony appearance and resistance due to genetic alterations, mostly affecting the cell envelope and metabolic functions.