Karlowsky JA, et al. J Pediatric Infect Dis Soc 2020.
BACKGROUND: Studies describing the activity of imipenem/relebactam against gram-negative bacilli (GNB) isolated from pediatric patients are lacking in the peer-reviewed literature. We address this deficiency by reporting on GNB tested against imipenem/relebactam as part of the Study for Monitoring Antimicrobial Resistance Trends global surveillance program.
METHODS: In 2015-2017, 221 laboratories in 59 countries collected 9149 consecutive, aerobic or facultative GNB from pediatric patients (age <18 years) and 100 785 from adult patients with intraabdominal, respiratory, and urinary tract infections. Susceptibility was determined using Clinical and Laboratory Standards Institute (CLSI) broth microdilution methodology and CLSI breakpoints (and US Food and Drug Administration breakpoints for imipenem/relebactam).
RESULTS: The 4 most common species of GNB isolated from pediatric patients were Escherichia coli (40.4%), Pseudomonas aeruginosa (17.1%), Klebsiella pneumoniae (13.9%), and Enterobacter cloacae (4.7%); non-Morganellaceae Enterobacterales (NME) accounted for 70.1% of isolates. Imipenem/relebactam inhibited 97.8% of NME from pediatric patients; susceptibility to imipenem was 1.9% lower, and susceptibility to β-lactam comparators (cefepime, ceftazidime, ceftriaxone, piperacillin/tazobactam) was 9.2-25.2% lower. Imipenem/relebactam inhibited 94.2% of P. aeruginosa from pediatric patients; susceptibility to imipenem was 16.2% lower, and susceptibility to β-lactam comparators was 10.2-15.6% lower. Susceptibility was generally slightly higher for isolates from pediatric than adult patients. All K. pneumoniae carbapenemase (KPC)-positive isolates, 93.3% of multidrug-resistant (MDR) NME isolates, and 70.5% of MDR P. aeruginosa isolates from pediatric patients were susceptible to imipenem/relebactam.
CONCLUSIONS: Imipenem/relebactam provides a new treatment option for infections caused by resistant gram-negative bacilli, including KPC-positive NME, MDR NME, and MDR P. aeruginosa.