Evaluation with E-test of the meropenem/vaborbactam association in carbapenem-resistant and sensitive negative control strains isolates of samples processed at the Laboratory of the Rivoli Hospital

Background and aims: Meropenem (Mer) and vaborbactam (Vab) is a combination of a carbapenem and a new β-lactamase inhibitor used in adults to treat different types of infections caused by Gram-negative bacteria. This combination is chosen as an alternative in infections caused by Gram-negative bacteria when carbapenem-only therapies are unsatisfactory. Materials and methods: Based on this, we report our assessment of such meropenem/vaborbactam association through the E-test and the Microscan routine automated system. This evaluation was performed on 22 samples, carbapenem-resistant strains of Gram-negative bacteria isolated from different types of biological material. Five E. coli and 1 P. mirabilis were respectively susceptible to both carbapenems and Mer/Vab, 6 P. aeruginosa and 2 A. baumannii were respectively resistant to both carbapenems and Mer/Vab and out of 8 K. pneumoniae which were resistant to carbapenems only one was resistant to the Mer/Var combination. Results and conclusions: From the data obtained, it can be seen that resistance to carbapenems is 72%, and drops to 36% with the combined use of Mer/Vab. However, this combination cannot be used in the treatment of patients with diseases caused by P. aeruginosa and Acinetobacter spp., resistant to meropenem.