Microbiology and antibiotic susceptibility of organisms in bile cultures from patients with and without cholangitis at an Asian academic medical center.

PURPOSE

To review the epidemiology of microbial isolates from bile cultures taken from patients with and without cholangitis admitted to an Asian academic medical center in order to compare antimicrobial sensitivities and to make recommendations for empiric antimicrobial therapy of patients with cholangitis in the Philippines.

METHODS

Routine aerobic bile culture results and corresponding clinical abstracts of surgical patients admitted to an academic medical center over a three-year period were analyzed.

RESULTS

The series consisted of 125 patients, 77 with cholangitis (62%) and 48 (38%) without, which was determined according to the Tokyo Guidelines. Patients with cholangitis were significantly more likely to have positive bile cultures (p = 0.012). Gram-negative bacilli were the most common isolates in both patients with (94%) and patients without (95%) cholangitis. For both groups, Escherichia coli (36%) had greatest sensitivity to amikacin, cefepime, ceftriaxone, gentamicin, imipenem-cilastatin meropenem, and piperacillin-tazobactam; Klebsiella pneumoniae (16%) had greatest sensitivity to amikacin, cefepime, ceftriaxone, gentamicin, imipenem-cilastatin meropenem, and piperacillin-tazobactam; and Pseudomonas aeruginosa (12.5%) was most sensitive to cefepime, gentamicin, imipenem-cilastatin meropenem, and piperacillin-tazobactam.

CONCLUSIONS

Gram-negative bacilli (or Enterobacteriaceae) (E. coli, K. pneumoniae, P. aeruginosa, and Enterobacter cloacae) were the most common aerobic microbial isolates in bile cultures from patients with cholangitis in the Philippines. Their antimicrobial susceptibility patterns suggest that imipenem-cilastatin (sensitivity 100%), meropenem (100%), amikacin (90-100%), cefepime (75%-100%), ceftriaxone (75%-100%), gentamicin (67%-100%), and piperacillin-tazobactam (50%-100%) would be the most effective antimicrobials for both groups. However, the authors echo the caution from the Surgical Infection Society/Infectious Diseases Society of America against using aminoglycosides as empiric drugs when safer and equally effective regimens are available.