Isolation of the first IMP-4 metallo-β-lactamase producing Klebsiella pneumoniae in Tianjin, China

This study shows for the first time the mechanism of carbapenem resistance of a Klebsiella pneumoniae clinical isolate TJ8 recovered from Tianjin Medical University General Hospital ,China. The modified Hodge test and EDTA synergy test were performed for the screening of carbapenemases and metallo-β-lactamases (MBLs), respectively. Polymerase chain reactions and DNA sequencing confirmed that the strain carried IMP-4 metallo-β-lactamase (MBL) , SHV-11 and TEM-1 β-lactamase. Class I integron was positive and gave a 3.0-kb PCR amplicon .IMP-4 was located in Class I integron 5’CS. The gene determinants were organized in the order of bla(IMP-4)-orfII-orfIII.In all, the results show that IMP-4 MBL production caused the TJ8 resistance to carbapenems.