Antimicrobial susceptibility of gram-negative strains isolated from bloodstream infections in China: Results from the study for monitoring antimicrobial resistance trends (SMART) 2018–2020

The study aims were to present in vitro susceptibilities of clinical isolates from Gram-negative bacteria bloodstream infections (GNBSI) collected in China. GNBSI isolates were collected from 18 tertiary hospitals in 7 regions of China from 2018 to 2020. Minimum inhibitory concentrations were assessed using a Trek Diagnostic System. Susceptibility was determined using CLSI broth microdilution, and breakpoints were interpreted using CLSI M100 (2021). A total of 1,815 GNBSI strains were collected, with <i>E. coli</i> (42.4%) and <i>Klebsiella pneumoniae</i> (28.6%) being the most prevalent species, followed by <i>P. aeruginosa</i> (6.7%). Susceptibility analyses revealed low susceptibilities (<40%) of ESBL-producing <i>E. coli</i> and <i>K. pneumonia</i> to third-/fourth-generation cephalosporins, monobactamases, and fluoroquinolones. High susceptibilities to colistin (95.0%) and amikacin (81.3%) were found for <i>K. pneumoniae</i>, while <i>Acinetobacter baumannii</i> exhibited a high susceptibility (99.2%) to colistin but a low susceptibility to other antimicrobials (<27.5%). Isolates from ICUs displayed lower drug susceptibility rates of <i>K. pneumoniae</i> and <i>A. baumannii</i> than isolates from non-ICUs (all <i>P</i> < 0.05). Carbapenem-resistant and ESBL-producing <i>K. pneumoniae</i> detection was different across regions (both <i>P</i> < 0.05). <i>E. coli</i> and <i>K. pneumoniae</i> were major contributors to GNBSI, while <i>A. baumannii</i> exhibited severe drug resistance in isolates obtained from ICU departments.