Susceptibility testing of biliary bacteria obtained before bile duct manipulation

Area of Science:

• Microbiology
• Infectious Diseases
• Gastroenterology

Background:

• Biliary tract infections are a concern during procedures for retained biliary stones.
• Understanding the microbial landscape of the biliary tract is crucial for effective treatment.

Purpose of the Study:

• To characterize bacterial isolates from bile in patients undergoing biliary stone extraction.
• To assess the susceptibility of these bacteria to antibiotics.
• To evaluate the risk of sepsis and recommend prophylactic strategies.

Main Methods:

• Bile cultures and susceptibility testing were performed on 41 patients prior to biliary tract manipulation.
• Organisms were identified, and their antibiotic sensitivities were determined.
• Clinical outcomes, including sepsis development, were monitored.

Main Results:

• Bile bacteria were identified in 90% of patients, with Gram-negative aerobes (e.g., Klebsiella pneumoniae) being most common.
• Enterococcus species were the most representative Gram-positive aerobes.
• Fifteen percent of patients developed sepsis; synergistic ampicillin and aminoglycoside therapy showed high effective coverage (97% for aerobes, 88% for anaerobes).

Conclusions:

• Prophylactic antimicrobial therapy is recommended for high-risk patients, including those who are debilitated, undergoing instrumentation of obstructed bile ducts, or choledochoscopy.
• Empiric antibiotic selection should consider the prevalence of Gram-negative and Gram-positive aerobes and anaerobes.
• Effective antibiotic combinations can mitigate the risk of sepsis in this patient population.