A Retrospective Study on Bile Culture and Antibiotic Susceptibility Patterns of Patients with Biliary Tract Infections

Abstract

Aim. This study aimed to provide profiles of microorganisms isolated from bile and antibiotic susceptibility patterns of biliary tract infections (BTIs) in our center. Methods. A total of 277 patients diagnosed with BTIs at the Second Affiliated Hospital of Harbin Medical University from 2011 to 2018 were included in this study. Medical records were reviewed to obtain clinical and demographic data. Bile specimens were prepared through endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiodrainage (PTCD), and percutaneous transhepatic gallbladder drainage (PTGD) under aseptic conditions. In those with positive bile culture results, blood cultures were concurrently conducted. The concordance of the results between bile culture and blood culture were also analysed. Results. Two hundred and sixty-seven bile cultures were positive, while 280 strains of micro-organisms were isolated. Among these, 76.8% were Gram-negative, 22.5% were Gram-positive and 0.7% were fungi. The most common microorganisms were Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. Gram-negative bacteria we tested were highly sensitive to ertapenem, imipenem, tigecycline, and amikacin. Gram-positive bacteria we tested were highly sensitive to tigecycline, teicoplanin, linezolid, vancomycin, and chloramphenicol. For the 44 patients with positive bile cultures, a blood culture was also performed. Among them, 29 cases yielded positive blood culture results. Among those cases with positive blood culture, 48.3% showed complete agreement with bile culture, 3.4% showed partial agreement, and 48.3% showed disagreement. The most common microorganisms in blood culture were the same as in bile culture. Additionally, the proportion of Staphylococcus epidermidis was significantly higher in blood culture ( $P<0.05$ ). Conclusion. Our study provided a comprehensive analysis of the bacteria distribution and drug resistance profiles in patients with BTIs in northern China. Further studies should be conducted to validate our findings.