Temporal Trends in Antimicrobial Resistance and Risk Factors in Patients with Pyogenic Liver Abscess: A Four-Year Cross-Sectional Study

Background: Pyogenic liver abscess (PLA) is a serious liver infection, particularly common in patients with immune deficiencies or chronic liver diseases. Given the rising antimicrobial resistance in PLA-associated pathogens, this study aimed to investigate the temporal trends in antimicrobial resistance and associated risk factors in PLA patients over a four-year period. Materials and Methods: This cross-sectional study was conducted at Tianjin First Center Hospital, China, by reviewing the medical records of PLA patients from January 2019 to December 2023. Patients were categorized into two groups: Klebsiella pneumoniae (KPLA) and non-Klebsiella pneumoniae (NKPLA). Data on clinical characteristics, laboratory results, imaging findings, microbiological culture results, and antimicrobial susceptibility patterns were collected. Temporal changes in antimicrobial resistance and associated risk factors were analyzed. Results: A total of 328 patients were included, of whom 297 (90.5%) were infected with Klebsiella pneumoniae (KPLA) and 31 (9.5%) with non-Klebsiella pathogens (NKPLA). Over the four-year period, the number of PLA cases gradually increased, with K. pneumoniae remaining the predominant pathogen. Resistance to ceftriaxone (20% in 2019 and 20% in 2023) and ciprofloxacin (25% in 2019 and 23% in 2023) showed slight variations, while carbapenem resistance decreased (imipenem: 7% in 2019 and 4% in 2023, meropenem: 6% in 2019 and 4% in 2023). In comparing the KPLA and NKPLA groups, KPLA patients were more likely to have diabetes (61.6% vs. 38.7%, P=0.01) and cryptogenic origin (65.7% vs. 41.9%, P<0.05). NKPLA cases had higher prevalence of hepatobiliary disease (32.3% vs. 18.2%, P=0.04) and malignancy (19.4% vs. 8.8%, P=0.03). Conclusion: This study highlights the increasing antimicrobial resistance in K. pneumoniae and E. coli associated with PLA, underscoring the need for updated local antibiograms and revised empirical therapy protocols. Furthermore, the clinical and microbiological differences between KPLA and NKPLA suggest that pathogen-specific and resistance-based stratification should replace traditional classifications.