Detection and Characterization of <i>β</i>-Lactamase Encoding Genes in Carbapenem Non-Susceptible Gram-Negative Bacteria and Susceptibility of Isolates to Ceftazidime-Avibactam at a New York City Community Hospital

A surveillance study was undertaken to identifyprominent β-lactamase encoding genesin 131 carbapenemnon-susceptible gram-negative clinical isolates at a New York City community hospital. KPC carbapenemases weredetected in 89% of Enterobacteriaceae as well as additional TEM, SHV, and CTX-Mclass A enzymes. OXA-23 and OXA-24 were the prevalent class D carbapenemasesidentified in Acinetobacter species.One OXA-23 in M. morganii and oneOXA-48 in K. pneumoniae were alsoidentified. Among class C β-lactamasesCMY, ACT/MIR, DHA, and FOX were detected. The in vitro activity of ceftazidime-avibactam by E-test methodologywas tested with minimal inhibitory concentrations (MIC) of ≤3 μg/ml for 97.8%of all Enterobacteriaceae, MIC50/90 of 16/u003e256 μg/ml for carbapenemnon-susceptible Acinetobacter, and3/6 μg/ml for carbapenem non-susceptible Pseudomonasaeruginosa. Periodic surveillance of isolates to characterize current and emerging β-lactamase genotypes present in localisolates may help identify outbreak situations, provide assistance to infectioncontrol and antibiotic stewardship programs, and potentially improve patientoutcomes.