A Seven-Year Microbiological and Molecular Study of Bacteremias Due to Carbapenemase-Producing Klebsiella Pneumoniae : An Interrupted Time-Series Analysis of Changes in the Carbapenemase Gene's Distribution after Introduction of Ceftazidime/Avibactam.

Background: Ceftazidime/avibactam (CZA) is a new option for the treatment of KPC-producing Klebsiella pneumoniae. The aim of this study was to determine resistance patterns and carbapenemase genes among K. pneumoniae (CP-Kp) bacteremic isolates before and after CZA introduction. Methods: K. pneumoniae from blood cultures of patients being treated in a Greek university hospital during 2015–21 were included. PCR for bla_KPC, bla_VIM, bla_NDM and bla_OXA-48 genes was performed. Results: Among 912 K. pneumoniae bacteremias: 725 (79.5%) were due to carbapenemase-producing isolates; 488 (67.3%) carried bla_KPC; 108 (14.9%) bla_VIM; 100 (13.8%) bla_NDM; and 29 (4%) carried a combination of bla_KPC, bla_VIM or bla_NDM. The incidence of CP-Kp bacteremias was 59 per 100,000 patient-days. The incidence of CP-Kp changed from a downward pre-CZA trend to an upward trend in the CZA period (p = 0.007). BSIs due to KPC-producing isolates showed a continuous downward trend in the pre-CZA and CZA periods (p = 0.067), while BSIs due to isolates carrying bla_VIM or bla_NDM changed from a downward trend in the pre-CZA to an upward trend in the CZA period (p < 0.001). Conclusions: An abrupt change in the epidemiology of CP-Kp was observed in 2018, due to the re-emergence of VIM-producing isolates after the suppression of KPC-producing ones via the use of CZA. [ABSTRACT FROM AUTHOR]