Prevalence and Significance of Fluoroquinolone Resistant Escherichia coli in Patients Undergoing Transrectal Ultrasound Guided Prostate Needle Biopsy

PurposeWe estimated the prevalence of fluoroquinolone resistant Escherichia coli in patients undergoing repeat transrectal ultrasound guided prostate needle biopsy and identified high risk groups.Materials and MethodsFrom January 2009 to March 2010 rectal swabs of 136 men from 3 institutions undergoing transrectal ultrasound guided prostate needle biopsy were obtained. There were 33 men with no previous biopsy who served as the controls. Participants completed questionnaires and rectal swab culture was obtained just before performing the prostate biopsy. Selective media was used to specifically isolate fluoroquinolone resistant E. coli and sensitivities were obtained. The patients were contacted via telephone 7 days after the procedure for a followup questionnaire.ResultsA total of 30 patients had cultures positive for fluoroquinolone resistant bacteria for an overall rate of 22% (95% CI 15, 29). Patients with diabetes and Asian ethnicity had higher risks of resistant rectal flora colonization (OR 2.3 and 2.8, respectively). However, differences did not reach statistical significance (p = 0.09 and p = 0.08, respectively). Patients with no prior biopsy had a positive rate of 15% (5 of 33) compared to 24% (25 of 103) in those with 1 or more prior biopsies (OR 1.8, p = 0.27). Five patients (3.6%) had post-biopsy fever while only 1 of those patients had a positive rectal swab.ConclusionsUsing selective media to isolate fluoroquinolone resistant E. coli from the rectum before transrectal ultrasound guided prostate biopsy, we isolated organisms in 22% of patients with a wide resistance pattern. This protocol may be used to provide information regarding targeted antibiotic prophylaxis before transrectal prostate biopsies.