Risk factors, outcomes and genotypes of carbapenem-nonsusceptible Klebsiella pneumoniae bloodstream infection: a three-year retrospective study in a large tertiary hospital in Northern China

Objective: To investigate the independent risk factors, outcomes and genotypes associated with carbapenem-non-susceptible K. pneumoniae bloodstream infections (BSIs) in northern China from 2014 to 2016. Methods: Over a three-year period, a total of 289 K. pneumoniae BSI patients were identified. Medical records were extracted to obtain the clinical information. Polymerase chain reactions (PCRs) were performed to analyse the multilocus sequence typing (MLST) types, Klebsiella pneumoniae carbapenemase (KPC) and metallo-fi-lactamases (MBL) genes, for replicon typing of the 10 randomly selected carbapenem-non-susceptible K. pneumoniae. Results: A total of 59 carbapenem-non-susceptible K. pneumoniae strains were identified. Resistance rates to imipenem, meropenem, ertapenem and amikacin were low. Multivariate analyses showed that a central venous catheter odds ratio (OR) of 4.021 (CI 1.002-16.134); mechanical ventilation of 7.587 (2.856-20.156); Pitt bacteraemia score of 1.481 (CI 1.218-1.800); hospitalization prior to culture of 1.026 (CI 1.001-1.053); and some antibiotic use 30 days prior to K. pneumoniae bacteremia, including carbapenem of 9.123 (CI 2.995-27.791), aminoglycoside of 34.079 (2.091-555.396), and tigecycline of 5.065 (CI 1.261-20.339) were associated with carbapenem-non-susceptible K. pneumoniae bacteremia. Sequence type 11 (ST11) was the most predominant MLST type, which accounted for 50% of the isolates. Eighty per cent of the isolates harbored the KPC-2 gene. The overall 28-day mortality rates of carbapenem-non-susceptible and carbapenem-susceptible K pneumoniae were 54.24% and 19.56%, respectively. Conclusion: Central venous catheter, mechanical ventilation, high Pitt bacteraemia score, hospitalization prior to culture, and prior antibiotic use (carbapenem, aminoglycoside and tigecycline) were identified as independent risk factors for carbapenem-non-susceptible K. pneumoniae BSI, which was mostly caused by KPC-2 in northern China.