Klebsiella pneumoniae liver abscess as the herald of underlying colorectal neoplasm

Abstract Background Klebsiella pneumoniae liver abscesses (KPLA) remain endemic to Taiwan. Hypervirulent strains in the gut can translocate across colonic mucosal defects into the portal circulation, causing subsequent liver abscesses. Occult colorectal cancer in patients with KPLA has been reported in a case series. Herein, we determined whether the diagnosis of KPLA serves as a harbinger of colorectal neoplasms. Methods Consecutive patients with KPLA treated at Taipei Veterans General Hospital in Taiwan between April 2011 and January 2024 were retrospectively enrolled. Hypervirulent K. pneumoniae strains were defined as those harbouring mutations in rmpA or rmpA2. Patients who underwent colonoscopy within 6 months of diagnosis were included in the analysis. Logistic regression was used to assess the risk factors for colorectal adenomas and adenocarcinomas. Results A total of 489 KPLA patients were identified during the study period, of which 114 (23.3%) underwent colonoscopy within 6 months of the diagnosis of KPLA. Most K. pneumoniae strains were hypervirulent (95.1%). Colonoscopy findings showed 48 (42.1%) cases of adenomas and 13 (11.4%) of adenocarcinomas. Age ≥ 50 years was the only independent factor for colorectal adenoma/adenocarcinoma (odds ratio = 5.728, 95% confidence interval = 2.045–16.04, P = 0.001). During follow-up, most patients with adenocarcinoma (11/13, 84.6%) remained disease-free post-surgery. Of the 48 patients with adenomas, 2 developed colorectal cancer. Conclusion Colorectal adenomas and adenocarcinomas are common in patients with KPLA. Colonoscopy should be routinely performed in KPLA patients, particularly those aged ≥ 50 years.