Bacterial Distribution and Antimicrobial Resistance in Intra-Abdominal Infections: A Five- Year Study in Jiaxing, China

Background Intra-abdominal infections (IAIs) represent a common and serious clinical condition, often caused by polymicrobial pathogens. The increasing prevalence of antimicrobial resistance among these pathogens poses a growing challenge to effective treatment and public health. Objective To investigate the distribution of bacterial isolates from IAIs patients and their antimicrobial resistance patterns, providing a basis for empirical anti-infective therapy and rational antimicrobial use in clinical practice. Methods Clinical data, pathogen distribution, and antimicrobial resistance profiles were collected from specimens of IAI patients submitted to the Jiaxing First Hospital between 2019 and 2023. Statistical and retrospective analyses of clinical and microbiological characteristics were conducted using WHONET 5.6 and SPSS 25.0. Results A total of 3,154 bacterial isolates were identified, with Escherichia coli and Klebsiella pneumoniae being the predominant Gram-negative pathogens (64.4%). Escherichia coli showed high resistance to ampicillin (> 60%) and moderate resistance to cephalosporins and fluoroquinolones, but remained highly susceptible to carbapenems and tigecycline. Klebsiella pneumoniae had similar trends with slightly lower resistance overall. Pseudomonas aeruginosa and Acinetobacter baumannii were the main non-fermenters; the former was sensitive to aminoglycosides and carbapenems, while the latter showed extensive resistance. Gram-positive isolates (35.6%) were mainly Enterococcus faecium and Enterococcus faecalis , with the former showing high resistance to several agents. Most infections occurred in elderly males, especially during summer. Conclusion The most commonly isolated pathogens in intra-abdominal infections were Escherichia coli , Klebsiella pneumoniae , Pseudomonas aeruginosa , Acinetobacter baumannii , Enterococcus faecium , and Enterococcus faecalis . High resistance rates to multiple antimicrobial agents were observed among these pathogens. Antimicrobial resistance monitoring should guide empirical antibiotic therapy to ensure effective treatment of intra-abdominal infections.