Abstract: Objective: To investigate and analyse metallo-β-lactamases of Klebsiella Pneumonia in Tianjin Medical University General Hospital, for guiding the rational use of antibiotics therapy. Methods: One hundred and forty-two clinical strains of Klebsiella Pneumonia were collected , the modified Hodge test and the modified three-dimensional test were used to co-detect carbapenemase and the MBL encoding genes were amplified by PCR ;Kirby-Bauer method and VITEK2-Compact system were performed to detect the sensitivity of the antimicrobial agents against the Klebsiella Pneumoniae . Results: we found two metallo-beta-lactamase-producing strains in One hundred and forty-two clinical strains of Klebsiella Pneumonia, PCR indicated that the two strain carried IMPgenes. Aztreonam were sensitive to the Klebsiella pneumoniae metallo-beta-lactamase--producing strains, but carbapenems， penicillins and cephalosporins antibiotics were resisitant. Conclusions: It is already detected metallo-β-lactamases in Klebsiella pneumoniae in Tianjin. The production of enzyme is the main mechanisms of carbapenem-resistant in Klebsiella pneumoniae.

Key words: Klebsiella Pneumoniae, carbapenemases, metallo-beta-lactamases, PCR