Microbial spectrum and drug resistance of pathogens cultured from gallbladder bile specimens of patients with cholelithiasis: A single-center retrospective study

World J Gastrointest Surg. 2022 Dec 27;14(12):1340-1349. doi: 10.4240/wjgs.v14.i12.1340.

Abstract

Background: Bacterial infection is an important cause of cholelithiasis or gallstones and interferes with its treatment. There is no consensus on bile microbial culture profiles in previous studies, and identified microbial spectrum and drug resistance is helpful for targeted preventive and therapeutic drugs in the perioperative period.

Aim: To analyze the bile microbial spectrum of patients with cholelithiasis and the drug susceptibility patterns in order to establish an empirical antibiotic treatment for cholelithiasis-associated infection.

Methods: A retrospective single-center study was conducted on patients diagnosed with cholelithiasis between May 2013 and December 2018.

Results: This study included 185 patients, of whom 163 (88.1%) were diagnosed with gallstones and 22 (11.9%) were diagnosed with gallstones and common bile duct stones (CBDSs). Bile culture in 38 cases (20.5%) was positive. The presence of CBDSs (OR = 5.4, 95%CI: 1.3-21.9, P = 0.03) and longer operation time (> 80 min) (OR = 4.3, 95%CI: 1.4-13.1, P = 0.01) were identified as independent risk factors for positive bile culture. Gram-negative bacteria were detected in 28 positive bile specimens, and Escherichia coli (E. coli) (19/28) and Klebsiella pneumoniae (5/28) were the most frequently identified species. Gram-positive bacteria were present in 10 specimens. The resistance rate to cephalosporin in E. coli was above 42% and varied across generations. All the isolated E. coli strains were sensitive to carbapenems, with the exception of one imipenem-resistant strain. K. pneumoniae showed a similar resistance spectrum to E. coli. Enterococcus spp. was largely sensitive to glycopeptides and penicillin, except for a few strains of E. faecium.

Conclusion: The presence of common bile duct stones and longer operation time were identified as independent risk factors for positive bile culture in patients with cholelithiasis. The most commonly detected bacterium was E. coli. The combination of β-lactam antibiotics and β-lactamase inhibitors prescribed perioperatively appears to be effective against bile pathogens and is recommended. Additionally, regular monitoring of emerging resistance patterns is required in the future.

Keywords: Bacterial infection; Cholelithiasis; Drug resistance; Gallbladder bile culture.