Despite antimicrobial prophylaxis, transurethral procedures still carry a significant risk of postoperative urinary tract infection.^1,2 To guide urologists, the AUA has developed a best practice statement looking at perioperative antimicrobial prophylaxis,³ with the current recommendations offering a single dose of trimethoprim-sulfamethoxazole (TMP-SMX) or a first- or second-generation cephalosporin as the first-choice prophylaxis for most transurethral procedures. Second-line choices include amoxicillin/clavulanate or an aminoglycoside with or without ampicillin. There is an important caveat in this best practice statement, that urologists should turn to their local antibiograms when selecting a preferred regimen.

The best practice statement was initially written in 2008 (reviewed in 2011)⁴ and updated in 2019.³ After reviewing the new recommendations, we promptly changed our practice to use of TMP-SMX or cefazolin in most cases. Serendipitously, around the same time, we received an email from our hospital infection control, which contained updated antibiograms. We were surprised to find that for Escherichia coli (the most common cause of post-transurethral procedure infection^2,5), our hospital didn’t report first-generation cephalosporin (second-generation was approximately 90%) susceptibility and that TMP-SMX susceptibility was less than 80%. We began to change our regimen for transurethral procedures (we use ceftriaxone in the absence of positive culture data) and began to consider whether there was a better universal first-line choice for prophylaxis for transurethral procedures.

We analyzed national trends in antimicrobial resistance by evaluating antibiograms from 40 states, 22 of which provided state-level data.⁶ We focused on looking at E. coli, Klebsiella spp, methicillin-sensitive Staphylococcus aureus, and Proteus mirabilis as these are commonly identified agents of post-procedural infection. We focused on susceptibility patterns for antibiotics typically used for antimicrobial prophylaxis or for the treatment of urinary tract infection. These antibiotics included first-generation cephalosporins, third-generation cephalosporins, TMP-SMX, fluoroquinolones, penicillin combinations, and aminoglycosides. We were able to determine that there is high variability from state to state in the susceptibility to these antibiotics, and that both TMP-SMX and first-generation cephalosporins had poor coverage in many states. Figure 1 illustrates both the comparatively low effectiveness of TMP-SMX and first-generation cephalosporins, as well as the high variability in susceptibility from state to state. Given this, we found it improbable that there could be a nationwide relatively narrow-spectrum choice that would provide excellent coverage. So with this conclusion, the next step was to evaluate variability within a single state to determine if more regional/local guidelines would be appropriate.

Our home state of Missouri was used to test the next hypothesis—that there would be a good statewide choice that would provide high-level coverage across the state. We were able to obtain antibiogram data from 38 different hospitals across Missouri.⁷ The same common pathogens were used and antimicrobial susceptibilities were reviewed. There was a lot of variability in susceptibility across the state (Figure 2), with limited correlation among hospital characteristics and susceptibility. Several antibiotics, including aminoglycosides and third-generation cephalosporins, outperformed both TMP-SMX and first-generation cephalosporins in most settings.

Putting the nationwide and state-level analysis together, there does not appear to be a universally optimal relatively narrow-spectrum antimicrobial at any level. We recommend that urologists use their individual hospital antibiograms when choosing antimicrobial prophylaxis. In the absence of a local antibiogram, we would recommend that urologists consider antimicrobials that appear to have higher coverage on average, such as third-generation cephalosporins or aminoglycosides (or even ertapenem), as opposed to the current AUA recommendation of TMP-SMX or a first-generation cephalosporin. While not directly evaluated in transurethral procedures, similar action in colorectal surgery decreased infections without increasing antimicrobial resistance.^8,9

As many studies do, these studies have led to many more questions and potential areas of focus when considering antimicrobial prophylaxis recommendations. As noted in both the national and state-level studies, there were several locations in which data were missing or otherwise unobtainable even after several attempts. We would next seek to determine whether (1) physicians (urologists) know where to turn within their hospitals to locate this antimicrobial data, (2) urologists have used their local data to make treatment decisions or chose prophylaxis based upon AUA recommendations, and (3) changes in antimicrobial prophylaxis agent based on local antibiograms improve postoperative infections and complication rates.

Although antimicrobial perioperative antibiotic administration is standardized and even part of time-out procedures in the operating room, the choice of antibiotic has not been fully evaluated. Given the fluidity of antimicrobial susceptibility (both spatially and temporally), designing a good trial of this will require creativity or the use of very-broad-spectrum agents. Transurethral procedures are very common and postoperative infection rates are high relative to other surgeries. Therefore, while challenging, this area is ripe for improvement with the potential to impact a great number of patients.