Clinical and bacteriological characteristics of IMP-type metallo-β-lactamase-producing Pseudomonas aeruginosa

IMP-type metallo-β-lactamase-producing bacteria have recently emerged worldwide. We conducted a case-control study in which 69 inpatients harboring bla IMP -positive Pseudomonas aeruginosa and 247 control subjects with bla IMP -negative pathogens were investigated. Prolonged hospitalization, antineoplastic chemotherapy, corticosteroid therapy (P =.001), and indwelling urinary catheters (P =.04) were risk factors for isolation of blaI MP -positive pathogens. The predominant source was urine (P =.001). The duration of antibiotic treatment and the total dose (including of carbapenems) were significantly greater among case patients than among control subjects (P<.01). bla IMP -positive P. aeruginosa isolates were more frequently resistant to multiple drugs (P =.001) and caused more infections (P =.001) than bla IMP -negative pathogens. There were no significant differences in bacteriological outcome (P =.94); however, infection-related death was more frequent among case patients than among control subjects (P =.023 These results suggest that precautionary measures against the spread of bla IMP -positive isolates are needed, because, for most of such pathogens, no antibiotic is potent enough to be used as a single agent in treatment of infection.