BARCELONA—Switching from a quinolone to penicillin as prophylaxis in men who are undergoing transrectal ultrasound-guided biopsies of the prostate (TRUSP) may increase the risk of serious infectious complications after the procedure, according to data released at the 25th Anniversary European Association of Urology Congress.

“At least for now, we should stick with the longstanding proven strategy using quinolone-based antibiotics,” said Satoshi Hori, MBBS, MRCS, Academic Clinical Fellow in Urology at the University of Cambridge and West Suffolk Hospitals NHS Trust.

Dr. Hori and his co-investigators reviewed results in patients who underwent TRUSP during a recent 15-month period at the West Suffolk Hospital in Bury St. Edmunds because of an elevated PSA level, an abnormal finding on digital rectal examination (DRE), or both. 

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The first 119 patients in the series received oral ciprofloxacin 500 mg one hour before their procedure followed by a twice daily three-day course of 500 mg ciprofloxacin starting immediately afterwards. The next 110 patients had their procedure at a later date when the institution’s policy for antibiotic prophylaxis had switched to co-amoxiclav prophylaxis. These patients received co-amoxiclav 625 mg given orally one hour before the procedure which was continued three times a day for the next three days.

“Because of the emergence of antimicrobial resistance and troublesome Clostridium difficile infections, U.K. health authorities have been trying to persuade urologists to find effective alternative antibiotics to quinolone-based antibiotics in patients undergoing TRUSP biopsies,” Dr. Hori explained. “We wanted to determine whether changing antibiotic prophylaxis from a quinolone-based to a penicillin-based strategy had any bearing on the development of serious infectious complications following TRUSP biopsies.”

The study excluded patients who had been given an antibiotic prophylaxis strategy that was different from the strategies in the two distinct study cohorts because of prior hypersensitivity reactions and/or a clinical decision by the attending urologist.

Results showed a significantly lower rate of post-TRUSP sepsis in the ciprofloxacin group. Sepsis developed in two of 119 patients in the ciprofloxacin group (1.68%) compared with eight of 110 patients in the co-amoxiclav group (7.27%). Post-TRUSP sepsis was defined as pyrexia in which a non-urologic cause had been excluded that necessitated hospital admission within two weeks of the procedure. No patient in either antibiotic prophylaxis group experienced a C. difficile infection.

Since the completion of the study, Dr. Hori’s team has reverted to the quinolone-based antibiotic strategy for TRUSP biopsies. During the first eight months of last year, only four of 169 men (2.37%) who had the procedure developed sepsis afterwards.

To his surprise, he said, the study found that Escherichia coli was the only organism isolated from patients presenting with post-TRUSP sepsis, all of whom were sensitive to co-amoxiclav on microbiological testing. 

“This finding suggests that prophylaxis with co-amoxiclav failed to work either because the dose of the antibiotic was too low, the course of antibiotics too brief, there was poor absorption of antibiotic via the gastrointestinal tract or there was poor antibiotic penetration into the prostatic tissue,” Dr. Hori said. “All four factors may play a role, but we feel that poor prostate tissue penetration of co-amoxiclav probably is the major factor in its failure as an effective prophylaxis agent in preventing post TRUSP sepsis.  Ciprofloxacin, on the other hand, has excellent penetration into prostatic tissue.”