Prevalence of antimicrobial resistance in normal rectal flora of patients undergoing transrectal ultrasonography-guided prostate biopsy in Korea

Objectives: To determine the prevalence of antimicrobial resistance in the normal rectal flora of patients undergoing transrectal ultrasonography-guided prostate biopsy in Korea. Methods: Between May 2010 and October 2010, rectal swabs were cultured from patients before transrectal ultrasonography-guided prostate biopsy in three tertiary referral centers of Jeonbuk Province, Korea. Rectal swabs were collected using cotton-tipped culture swabs in a standard collection system immediately before prostate biopsy. The swabs were cultured on eosin methylene blue and McConkey agar at 37°C. Antimicrobial sensitivity tests were carried out according to National Committee for Clinical Laboratory Standards guidelines. Results: Of the 160 patients who had a rectal swab taken before prostate biopsy, microorganisms were isolated in 125 patients. Escherichia coli was isolated from the rectal swabs of 95 patients. The mean age was 68.1 years, the median serum prostate specific antigen was 5.6ng/mL and the mean prostate volume measured by transrectal ultrasonography was 43.8mL. Of the E.coli, 33.7%, 29.1%, 26.7%, 23.3%, 12.8%, 9.3%, 5.8%, 1.2% and 0% were resistant to ampicillin, piperacillin, levofloxacin, trimethoprim sulfamethoxazole, gentamicin, cephalothin, cefotaxim, amikacin and meropenem, respectively. Conclusions: There is a high level of resistance to ciprofloxacin and ampicillin, and a very low level of resistance to amikacin in the E.coli in the bowel flora. The prevalence of resistance to ciprofloxacin in Korea is significantly higher than that reported in Western countries.