Abstract: Objective To analyze the clinical characteristics, pathogen distribution, and antimicrobial susceptibility of liver abscess (LA) patients, to explore early warning indicators of septic shock, the association between cryptogenic liver abscess and tumor, the differentiation between LA and primary hepatocellular carcinoma (HCC), and the pathogen spectrum of invasive LA syndrome. Methods A retrospective analysis was conducted on clinical data of 146 LA patients admitted to the Affiliated Hospital of North Sichuan Medical College from June 1, 2020 to May 31, 2024. General situation, laboratory indices, microbiological results, and imaging features were collected to compare the difference between septic shock and non-shock groups. Results Among the 146 patients, 54.11% were male, with a mean age of 60.1 ± 13.1 years. Diabetes mellitus was present in 56.84% of cases, and hepatobiliary-pancreatic diseases in 52.05%. The main clinical manifestations included fever (69.18%) and abdominal pain (41.78%). Gram-negative bacteria were the predominant pathogens (82.53%), with Klebsiella pneumoniae being the most frequently isolated (65.06%), followed by Escherichia coli (10.24%). In the septic shock group, procalcitonin (PCT) and interleukin-6 (IL-6) were significantly higher than in the non-shock group (P<0.05), while platelet (PLT) levels were significantly lower (P<0.05). Cryptogenic liver abscess accounted for 52.74% of cases, including one patient subsequently diagnosed with ascending colon adenocarcinoma. Alpha-fetoprotein (AFP) levels were within normal limits in all 81 patients tested, while mildly elevated levels of protein induced by vitamin K absence or antagonist-Ⅱ (PIVKA-Ⅱ) were observed in 48 out of 67 patients. Pathogens such as Klebsiella pneumoniae, Escherichia coli, Enterobacter aerogenes, Streptococcus spp., Candida spp., and Clostridium perfringens were associated with invasive infections involving multiple sites, including the bloodstream, lungs, eyes, urinary tract, peritoneal cavity, spleen, and cervical soft tissues. Conclusion Liver abscess is primarily caused by Klebsiella pneumoniae infection. The proportion of Enterococcus was higher in portal vein infections. PLT, PCT, and IL-6 may serve as early warning indicators for septic shock. Patients with cryptogenic liver abscess should be monitored for potential underlying malignancies, and regular colonoscopy screening is recommended. Antimicrobial therapy should be optimized based on drug susceptibility results, with vigilance for drug-resistant bacteria and fungal co-infections. Combined detection of AFP and PIVKA-Ⅱ contributes to the differential diagnosis between liver abscess and hepatocellular carcinoma. Klebsiella pneumoniae, Escherichia coli, Enterobacter aerogenes, Streptococcus spp., Candida spp., and Clostridium perfringens are potential pathogens causing invasive liver abscess.

Key words: Liver abscess, Clinical features, Septic shock, Invasive infection