Antimicrobial Susceptibility of Enterobacteriaceae and Pseudomonas aeruginosa Isolates from United States Medical Centers Stratified by Infection Type: Results from the International Network for Optimal Resistance Monitoring (INFORM) Surveillance Program, 2015–2016

摘要

A total of 18,656Enterobacteriaceaeand 4,175Pseudomonas aeruginosawere consecutively collected from 85 US hospitals and tested for susceptibility by broth microdilution methods in a central monitoring laboratory (JMI Laboratories). The antimicrobial susceptibility and frequency of key resistance phenotypes were assessed and stratified by infection type as follows: bloodstream (BSI; 3,434 isolates; 15.0%), pneumonia (6,439; 28.2%), skin and skin structure (SSSI; 4,134; 18.1%), intra-abdominal (IAI; 951; 4.2%), and urinary tract (UTI; 7,873; 34.5%). Ceftazidime-avibactam was active against 99.9% to 100.0% ofEnterobacteriaceaeand 97.0% (pneumonia) to 99.4% (UTI) ofP. aeruginosaisolates. Susceptibility rates were consistently lower for β-lactams, such as ceftazidime (82.3% vs. 87.1–90.8%), piperacillin-tazobactam (87.5% vs. 90.2–95.6%), and meropenem (96.8% vs. 98.4–99.4%) amongEnterobacteriaceaefrom pneumonia compared to other infection types. Susceptibility to gentamicin was also generally lower among isolates from pneumonia, whereas susceptibility to levofloxacin and colistin were lowest among BSI and SSSI isolates, respectively. The occurrence of multidrug-resistance (MDR; 8.2% overall), extensively drug-resistance (XDR; 1.1% overall), and carbapenem-resistantEnterobacteriaceae(CRE; 1.3% overall) phenotypes were markedly higher among isolates from patients with pneumonia compared to other infection types. AmongP. aeruginosa, susceptibility rates for ceftazidime, piperacillin-tazobactam, and gentamicin were lowest among isolates from pneumonia, whereas susceptibility to meropenem was similar among isolates from BSI, pneumonia, and IAI (77.3–77.9%), and susceptibility to levofloxacin was markedly lower among UTI isolates (67.1%). The frequencies ofP. aeruginosaisolates with MDR and XDR phenotypes were highest among isolates from patients with pneumonia.