Analysis of bacterial spectrum and variability of drug resistance of bile in patients with common bile duct stones and biliary tract infections / 中华消化杂志

ABSTRACT

Objective:To analyze the distribution of pathogenic bacteria in bile culture in patients with common bile duct stones and biliary tract infections, in order to guide clinical optimization of antibiotics application.Methods:From March 30, 2017 to December 31, 2021, at Affiliated Hospital of Qingdao University, 753 patients with common bile duct stones and biliary tract infections and received endoscopic retrograde cholangiopancreatography were selected. Bile samples were obtained for bacterial culture, strain type identification and drug sensitivity test in order to analyze bile pathogenic bacteria distribution, change trend and drug resistance. Chi-square test was used for statistical analysis.Results:From 2017 to 2021, the total positive rate of bile culture in 753 patients with choledocholithiasis complicated with biliary tract infection was 90.17% (679/753). From 2017 to 2021, the positive rates of bile culture were 82.05% (64/78), 88.81% (119/134), 88.03% (125/142), 93.87% (199/212), and 91.98% (172/187), respectively, and the difference was statistically significant ( χ2=10.78, P=0.029). The positive rate of bile culture in 2017 was lower than those in 2020 and 2021, and the differences were statistically significant ( χ2=9.43 and 5.57, P=0.002 and 0.018). There were no significant differences in the positive rates of bile culture among the other years (all P>0.05). A total of 1 033 pathogenic bacteria were detected in the 679 bile specimens with positive bile culture results. Among which the total proportion of Gram-negative bacilli was 57.02% (589/1 033), and from 2017 to 2021 the proportions were 66.38% (77/116), 66.47% (111/167), 59.43% (104/175), 54.75% (173/316), and 47.88% (124/259), respectively. The total proportion of Gram-positive cocci was 41.05% (424/1 033), and from 2017 to 2021 the proportions were 31.90% (37/116), 31.74% (53/167), 38.86% (68/175), 44.30% (140/316), and 48.65% (126/259), respectively. The total proportion of fungus was 1.94% (20/1 033), and from 2017 to 2021 the proportions were 1.72% (2/116), 1.80% (3/167), 1.71% (3/175), 0.95% (3/316), and 3.47% (9/259), respectively. From 2017 to 2021, the proportion of Gram-negative bacilli gradually decreased, while the proportion of Gram-positive cocci gradually increased, and the differences were statistically significant ( χ2=20.14 and 17.91, P<0.001 and =0.001). From 2017 to 2021, the change in the proportion of fungus was not statistically significant ( P>0.05). The main Gram-negative bacilli in the bile culture were Escherichia coli (31.36%, 324/1 033) and Klebsiella pneumoniae (12.68%, 131/1 033); the main Gram-positive cocci were Enterococcus faecalis (14.04%, 145/1 033) and Streptococcus salivarius (4.36%, 45/1 033). From 2017 to 2021, the proportions of Escherichia coli were 39.66% (46/116), 38.92% (65/167), 33.14% (58/175), 28.48% (90/316), and 25.10% (65/259), respectively, with gradual decrease and the difference was statistically significant ( χ2=14.34, P=0.006). From 2017 to 2021 the detection rates of extended-spectrum β-lactamase (ESBL) in Escherichia coli and Klebsiella pneumoniae were 30.43% (14/46), 26.15% (17/65), 29.31% (17/58), 38.89% (35/90), 40.00% (26/65), and 4/15, 20.00% (5/25), 20% (5/25), 24.32% (9/37), and 31.03% (9/29), and there were no significant differences in the detection rates of ESBL between different years (both P>0.05). Conclusions:From 2017 to 2021, the positive rate of bile culture in patients with choledocholithiasis complicated with biliary tract infection showed an overall increasing trend. Gram-negative bacilli were still dominated in bile pathogenic bacteria, while the proportion of Gram-positive cocci remarkably increased, and the bile bacterial spectrum significantly changed. Clinicians should adjust the antibiotic dosing regimens according to the variation of bacterial spectrum and drug resistance.