%0 Case Reports
%T Meropenem/Vaborbactam Plus Aztreonam as a Possible Treatment Strategy for Bloodstream Infections Caused by Ceftazidime/Avibactam-Resistant Klebsiella pneumoniae: A Retrospective Case Series and Literature Review.
%A Belati A
%A Bavaro DF
%A Diella L
%A De Gennaro N
%A Di Gennaro F
%A Saracino A
%A Belati A
%A Bavaro DF
%A Diella L
%A De Gennaro N
%A Di Gennaro F
%A Saracino A
%A Belati A
%A Bavaro DF
%A Diella L
%A De Gennaro N
%A Di Gennaro F
%A Saracino A
%J Antibiotics (Basel)
%V 11
%N 3
%D Mar 2022 10
%M 35326836
%F 5.222
%R 10.3390/antibiotics11030373
%X <B>OBJECTIVE: </B>The aim of this study was to describe our experience of a combination treatment including meropenem/vaborbactam (M/V) plus aztreonam (ATM) for bloodstream infections (BSIs) due to ceftazidime/avibactam-resistant Klebsiella pneumoniae (CAZ/AVI-R-Kp), for which gene typing was not available at the time the blood culture (BC) results were obtained.<BR><B>METHODS: </B>Between 20 July and 22 August 2021, in our hospital laboratory, the molecular test for carbapenemase gene typing was not available. All Gram-negative bloodstream infections were recorded, and characteristics of patients were analysed. Among them, three patients had positive BCs for CAZ/AVI-R-Kp, and the empirical therapy was switched to M/V plus ATM pending phenotypic testing of sensitivity to M/V. Therapy was subsequently targeted on the basis of the results of this test.<BR><B>RESULTS: </B>KPC and NDM represent the most prevalent carbapenemases in our polyclinic. Three patients with CAZ/AVI-R-Kp sepsis were treated with M/V plus ATM not knowing the carbapenemase gene. Two had an NDM-Kp infection for which, upon obtaining the result of sensitivity to M/V, combination therapy was maintained. The third had KPC-Kp infection for which ATM was discontinued, after the acquisition of an antibiogram reporting full sensitivity to M/V (MIC = 0.25 mg/L). One patient with NDM-Kp infection died due to complications of the underlying disease for which he was hospitalised.<BR><B>CONCLUSIONS: </B>Meropenem/vaborbactam plus ATM and subsequent de-escalation could represent a possible therapeutic strategy in severe CAZ/AVI-R-Kp infections when carbapenemase gene typing is not rapidly available.