Material and Method: Between December 2012 and March 2013, 105 male patients who had prostate specific antigen (PSA) more than 4 ng/ml or abnormal digital rectal examination (DRE) underwent TRUS-Bx were enrolled. Two specimens of rectal swab for bacterial culture were taken from each patient. The first rectal swab was obtained at the beginning of the procedure (BC), another after cleaning the rectum with betadine solution (AC). All gram-negative enteric bacteria were isolated. The results of both specimens were analyzed by Chi-square test and McNemar test.

Results: One hundred five men that underwent TRUS-Bx were included in the present study. Of the 105 patients, 15 men were found to have no bacterial growth while 90 men showed bacterial growth at the BC procedure. After the AC procedure, 53 men (59%) remained having positive culture for bacterial strains (p<0.001), and 37 (41%) showed no bacterial growth. There was no change in the bacterial strains in 36 men while another four men demonstrated an increasing number of bacterial strains at the AC stage. Of 90 patients, 81 (90%) men carried ciprofloxacin resistant organisms including Escherichia coli (E. coli) (55.56%), extended-spectrum β-lactamase (ESBL)-producing E. coli (35.80%), Klebsiella pneumoniae (6.17%), and Enterobacter cloacae (2.47%).

Conclusion: Incidence of fluoroquinolone resistant organisms in rectum of men undergoing TRUS-Bx at Ramathibodi Hospital was approximately 90%. E. coli was the most common organism. The results indicated that rectal cleaning significantly decreases the incidence of overall bacterial colonization in rectum before TRUS-Bx.

Keywords: Fluoroquinolone resistant, Prostate biopsy, Prostate cancer, TRUS-Bx infection