Prevalence of antimicrobial resistance in intestinal flora of patients undergoing prostatic biopsy: implications for prophylaxis and treatment of infections after biopsy.

OBJECTIVE

To determine the prevalence of antimicrobial resistance in intestinal flora of patients undergoing transrectal ultrasonography (TRUS)-guided prostate biopsies (TGB) and to examine if this information is useful in selecting appropriate antimicrobial agents for prophylaxis and treatment of biopsy-associated infections.

PATIENTS AND METHODS

In 2007 and 2008, rectal swabs were cultured from patients before undergoing TGB. Antimicrobial sensitivity of coliforms to amikacin, ciprofloxacin and coamoxiclav was determined. Laboratory records were used to identify patients who had bacteraemia or significant bacteriuria within 30 days of the TGB and the antimicrobial sensitivity pattern of these organisms were compared to those from the rectal swab.

RESULTS

Of 592 patients who had TGB, 445 (75.1%) had a rectal swab beforehand; 0.2%,10.6% and 13.3% of the coliforms were resistant to amikacin, ciprofloxacin and coamoxiclav, respectively. After TGB, six patients presented with urinary tract infections (UTI) and two with bacteraemia. All the infections were caused by coliforms except one UTI which was caused by ciprofloxacin-sensitive Pseudomonas aeruginosa. The blood culture isolates were sensitive to amikacin but resistant to ciprofloxacin and coamoxiclav. All the coliforms in the urine were resistant to ciprofloxacin but sensitive to coamoxiclav. Urine isolates were not tested for amikacin sensitivity. There was a strong correlation between the antimicrobial sensitivity of the coliforms from the rectal swabs and those cultured from urine or blood in both patients for amikacin, six of eight for ciprofloxacin and seven of eight for coamoxiclav.

CONCLUSIONS

Our study shows that in the coliforms in the bowel flora of our local population there is a relatively high level of resistance to ciprofloxacin and coamoxiclav, and very low level of resistance to amikacin. As there was a strong correlation between the antimicrobial sensitivity of organisms causing infections after TGB and those isolated from the rectal swabs, we conclude that rectal swab cultures before TGB provide useful evidence for selecting appropriate antimicrobials for prophylaxis and treatment of TGB-associated infections.