Escherichia coli bloodstream infection after transrectal ultrasound-guided prostate biopsy: implications of fluoroquinolone-resistant sequence type 131 as a major causative pathogen.

Background: Transrectal ultrasound-guided (TRUS) prostate biopsy is a commonly performed procedure, and fluoroquinolones are the most frequently given prophylactic antimicrobials. In the context of increasing fluoroquinolone resistance, and the international emergence of fluoroquinolone-resistant sequence type 131 (ST131) Escherichia coli, we describe a large series of E. coli bacteremia after TRUS biopsy.

Methods: All male patients admitted with community-onset (CO) E. coli bacteremia from January 2006 through December 2010 were included. Patient characteristics, treatment outcomes, and rates of antimicrobial resistance were compared between patients with TRUS biopsy-related bacteremia and other male patients with CO E. coli bacteremia. Molecular typing was performed on E. coli isolates to determine phylogenetic group.

Results: A total of 258 male patients were admitted with CO E. coli bacteremia. Of these, 47 patients (18%) were admitted after TRUS biopsy. Patients who had undergone TRUS biopsy were twice as likely to require intensive care admission (25% vs 12%) and had significantly higher rates of resistance to gentamicin (43%), trimethoprim-sulphamethoxazole (60%), and ciprofloxacin (62%) as well as all 3 agents in combination (19%). Thirty-six percent of post-TRUS biopsy patients did not receive active empirical antibiotic therapy. The ST131 clone accounted for 41% of all E. coli isolates after TRUS biopsy.

Conclusions: E. coli bacteremia can be a life-threatening complication of TRUS biopsy. Infecting strains are frequently multidrug-resistant and resistant to common empirical antibiotic agents. E. coli ST131 is an important cause of sepsis after TRUS biopsy. Further studies should evaluate colonization with fluoroquinolone-resistant E. coli as a risk factor for postbiopsy sepsis.