Insertion sequences disrupting mgrB in carbapenem-resistant Klebsiella pneumoniae strains in Brazil.

OBJECTIVES: This study aimed to characterise insertional mutations disturbing themgrB gene in carbapenem-resistant Klebsiella pneumoniae (CRKp). METHODS: A total of 118 clinical CRKp isolates were surveyed for polymyxin resistance and insertion sequence (IS) elements disruptingmgrB. RESULTS: Of the 118 isolates, 78 (66.1%) displayed polymyxin resistance, of which 54% (42/78) hadmgrB::IS inserts. Sequencing analyses showed 13 insertion sites in mgrB. mgrB::ISSen4(IS3) was observed for the first time in CRKp. CONCLUSIONS: Ten different IS elements disruptedmgrB, with a predominance (76%) of IS5 sequences.