Objectives: To determine the mortality rate secondary to blaKPC Klebsiella pneumoniae (KPC/Kp) bacteraemia, compared with that from ESBL-producing K. pneumoniae (ESBL/Kp) bacteraemia, and to determine associated risk factors.
Methods: This was a retrospective case-control study of all 68 KPC/Kp bacteraemia patients diagnosed since 2006, matched by year of isolation, gender and age, at a ratio of 1:2, to 136 ESBL/Kp bacteraemia patients.
Results: There were no demographic differences between the two groups, but there were minor clinical differences. Fewer KPC/Kp study patients than ESBL/Kp control patients had a systolic blood pressure <90 mmHg (32/68, 47% versus 86/136, 63%, respectively, P = 0.02) or urinary catheterization (32/68, 47% versus 90/136, 66%, respectively, P = 0.005), while the KPC/Kp bacteraemia group had a greater incidence of acute renal failure (45/68, 66% versus 67/136, 49%, respectively, P = 0.02). There was no difference between the two groups in duration of hospitalization. The mortality rate of the KPC/Kp bacteraemia group was 44/68 (65%) compared with 54/136 (40%) in the ESBL/Kp bacteraemia control group (P = 0.008), which in the multivariate analysis remained highly significant (P < 0.001). Only 11/68 (16%) of KPC/Kp patients were functionally independent at discharge compared with 43/136 (32%) ESBL/Kp patients (P = 0.012).
Conclusions: The selection of an ESBL/Kp control cohort with a ratio of 1:2 (study versus control group) helped resolve an as yet insufficiently settled question: bacteraemia with KPC/Kp is an independent risk factor for death, justifying the strict adherence to cohorting and isolation procedures.
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