SELECTING APPROPRIATE ANTIBIOTIC PROPHYLAXIS FOR TRANSRECTAL PROSTATE BIOPSY IN AN ERA OF INCREASING ANTIMICROBIAL RESISTANCE

Purpose:

Transrectal prostate biopsy (TRPB) is used to diagnose prostate cancer and involves inserting biopsy needles through the rectal wall to access the prostate. Given the highly non-sterile conditions of the rectum, post-procedural complications are relatively common and include fever, urinary tract infections (UTI), and, in rare cases, sepsis. Antibiotic prophylaxis can greatly reduce the risk of TRPB-related complications; however, the efficacy of prophylaxis has been hampered by the rise of antibiotic resistance, leading healthcare providers to reconsider their prophylactic agent of choice. In this analysis, we seek to determine the optimal choice of antibiotic for TRPB prophylaxis as a function of the resistance profile of the patient population.

Method:

We developed a decision-analytic model of 30-day post-TRPB outcomes, including risks and utility decrements of fever, UTI, and sepsis, as well as sepsis-related mortality. We compared two antibiotics most commonly used for prophylaxis: ciprofloxacin (a fluoroquinolone) and trimethoprim-sulfamethoxazole (TMP-SMX) (a sulfonamide). Complication risks under each prophylactic regimen were stratified by whether the patient was colonized with bacteria sensitive or resistant to the relevant antibiotic class. The efficacy of each antibiotic in preventing post-procedure complications with sensitive bacterial strains was estimated from a meta-analysis of randomized control trials. We assumed that complication rates for patients colonized with bacteria resistant to the administered prophylaxis were the same as the placebo arms of randomized control trials.

Result:

Without resistance, TMP-SMX maximized 30-day post-TRPB quality of life, driven by its superior efficacy in preventing UTIs compared to ciprofloxacin. At current resistance levels among men undergoing TRPB (22% fluoroquinolone and 11% sulfonamide resistance), TMP-SMX was the prophylaxis of choice and remained so as long as the prevalence of sulfonamide resistance was no more than 9% higher than the prevalence of fluoroquinolone resistance. In the base case, TMP-SMX and ciprofloxacin were assumed to be equally effective at preventing sepsis. If TMP-SMX was less effective, ciprofloxacin was the agent of choice for current resistance levels if the probability of sepsis with TMP-SMX was more than 0.3% greater than with ciprofloxacin.

Conclusion:

At current antimicrobial resistance levels among men undergoing TRPB, TMP-SMX resulted in the best patient outcomes. If TMP-SMX resistance were to substantial increase or if TMP-SMX was found to be less effective in preventing sepsis, ciprofloxacin may result in better outcomes.