Clinical characteristics and etiological analysis in liver abscess: a retrospective study

This study aimed to investigate the distribution and antimicrobial resistance patterns of pathogens isolated from patients with liver abscess, and to correlate these findings with clinical characteristics, providing evidence for empirical antibiotic therapy.

A retrospective analysis of bacterial pathogen distribution, antimicrobial susceptibility patterns, and clinical characteristics in patients with liver abscess at a tertiary hospital was conducted from April 2019 to March 2025. Clinical and microbiological data were extracted from medical records. According to culture results, patients were classified into the culture-negative liver abscess (CNLA) and culture-positive liver abscess (CPLA) groups. The CPLA cases were further divided into Klebsiella pneumoniae liver abscess (KPLA), Escherichia coli liver abscess (ECLA), and other pathogen groups.

Multivariable logistic regression analysis showed that diabetes, malignant tumors, and hepatic insufficiency were independently associated with CPLA. Furthermore, diabetes was independently associated with KPLA, whereas malignant tumors were negatively associated with KPLA. Among the 297 CPLA patients, 326 pathogenic isolates were identified, including 271 patients with monomicrobial infections and 26 patients with polymicrobial infections. Klebsiella pneumoniae was the most frequently isolated pathogen (73.5%), followed by Escherichia coli (14.9%). Antimicrobial resistance pattern analysis revealed that 22.4% of isolates were multidrug-resistant, 10.4% were extended-spectrum b-lactamase (ESBL) producers, and 3.7% were carbapenem-resistant Enterobacterales (CRE).

CPLA and CNLA patients exhibited different clinical characteristics, with the latter posing a greater challenge to empirical therapy due to the lack of microbiological evidence. KPLA was more commonly associated with diabetes and generally maintained susceptibility to commonly used antimicrobial agents, whereas ECLA was more frequently associated with malignancy and biliary tract disease and demonstrated a higher antimicrobial resistance burden. For patients without microbiological evidence or with culture-negative results, empirical therapy should prioritize coverage of Enterobacterales, with treatment optimization based on subsequent susceptibility testing results.