Antimicrobial Resistance Trends and Epidemiological Characteristics of Isolates from Intra-Abdominal Infections in China: A 6-Year Retrospective Study (2017–2022)

<b><i>Background:</i></b> Antimicrobial resistance represents a continuing threat to the health of patients with intra-abdominal infections (IAIs). This study aimed to provide clinicians with guidance to optimize antibiotic therapy. <b><i>Methods:</i></b> The clinical data and antibiotic susceptibility results of pathogens from patients with IAIs from 2017 to 2022 were retrospectively collected. The 6-year period was segmented into two stages, namely, the early (2017-2020) and recent stages (2021-2022). The distribution and antibiotic resistance of pathogens were compared between the stages. <b><i>Results:</i></b> In total, 5,795 pathogens were isolated from 2,283 patients diagnosed with IAIs. Gram-negative bacteria, Gram-positive bacteria, and fungi accounted for 71.0%, 21.4%, and 7.5% of the isolates, respectively. <i>Klebsiella pneumoniae</i> (1,037, 17.9%) was the primary isolate. The proportion of extended-spectrum β-lactamase-producing <i>Enterobacteriaceae</i> was 89.8% (2,028/2,259), with extended-spectrum β-lactamase-producing <i>Escherichia coli</i> and <i>K. pneumoniae</i> accounting for 27.4% and 43.2%, respectively, of all such isolates. The carbapenem resistance rates of <i>E. coli</i> and <i>K. pneumoniae</i> were 17.1% and 75.9%, respectively. Compared with that in the early stage, the imipenem resistance rate of <i>E. coli</i> was significantly higher in the recent stage (13.8% vs. 25.1%, p < 0.001). Among Gram-positive bacteria, 88 strains of vancomycin-resistant <i>Enterococcus</i> were detected, giving a resistance rate of 10.3%, and the detection rate of methicillin-resistant <i>Staphylococcus aureus</i> was 65.7%. <b><i>Conclusions:</i></b> <i>Enterobacteriales</i> and non-fermentative bacteria from IAIs remain highly resistant to carbapenems. The epidemiological characteristics and antibiotic resistance profiles of pathogens in various regions should be closely monitored to mitigate the appearance of drug-resistant bacteria in clinical settings.