The routine use of rectal swabs to identify less common and potentially more dangerous forms of bacteria could be very useful in prevention of infection prior to any type of biopsy for risk of prostate cancer.
A paper by Taylor et al. published in 2012 (and discussed on this web site) had previously concluded that:
Targeted antimicrobial prophylaxis was associated with a notable decrease in the incidence of infectious complications after transrectal ultrasound guided prostate biopsy caused by fluoroquinolone resistant organisms as well as a decrease in the overall cost of care.
Now another paper, dealing very specifically with the risks associated with biopsy and infection by ciprofloxacin-resistant forms of E. coli bacteria, seems to come to very similar conclusions. (E. coli is a bacterium that is extremely common in the human gastrointestinal system; ciprofloxacin-resistant forms of this bacterium that get into the blood stream can lead to serious forms of systemic infection that are difficult to treat.)
Dai et al. report that, at their institution, all patients scheduled to receive a prostate biopsy between February 2013 to February 2014 were included received either a pre-biopsy rectal swab and culture-directed antimicrobial prophylaxis or routine fluoroquinolone antibiotics. (This paper is also discussed on the Science Daily web site.) They found that:
- 314/487 patients (Group A) were given rectal swabs and culture-directed antimicrobial prophylaxis.
- 173/487 patients (Group B) were given routine fluoroquinolone prophylaxis.
- Men in Group B were, on average, very slightly older than men in Group A.
- There was no significant difference in average (mean) PSA levels, Charlson comorbidity scores, or ethnicity between the men in Group A and Group B.
- Men in Group A were more likely to receive supplemental gentamicin prophylaxis (P < 0.001) and had fewer infectious complications (1.9 vs 2.9 percent; P = 0.5).
- A decreased risk of infection was associated with use of culture-directed antibiotics among men in Group A compared to men in Group B (odds ratio, 0.70).
- The incidence of fluoroquinolone resistance and extended-spectrum beta-lactamase production was 12.1 percent for men in Group A and 0.64 for men in Group B.
Dai et al. conclude that their study was too small to provide definitive data, but does suggest that
… there are lower odds of infection with rectal swab-directed antimicrobial prophylaxis.
They note that the incidence of fluoroquinolone resistance is high in their local area and recommend that a prospective, randomized, controlled clinical trial is warranted to further evaluate the use of rectal swabs and targeted antibiotic prophylaxis prior to transrectal biopsy.
THE "NEW" PROSTATE CANCER INFOLINK 
Thank you for posting this information, as fear of getting a serious infection after a prostrate biopsy can be a reason for postponing a prostate biopsy when one probably should not delay in getting such a biopsy, particularly if recommended by one’s urologist for good reasons.
The bad news about getting a rectal culture for Cipro-resistant organisms is that they may not be frequently done and available in one’s area, but if one encounters this situation, calling around could enable one to get the culture done after all.
The good news about prostate biopsy infections is that they are decreasing because many urologists (per AUA recommendations) are now giving all prostate biopsy patients a shot of antibiotics just before the prostate biopsy in addition to the oral Cipro before and after the biopsy. All these patients receiving antibiotic shots will not have had the rectal cultures beforehand.
If one is slated to get a TRUS prostate biopsy and rectal cultures are not available, a good question to ask the urologist pre-biopsy would be: “Do you routinely give patients a shot of antibiotics pre-biopsy?”
Not mentioned are ways to prepare the rectal area pre-biopsy that may also be helpful, and also trans-peritoneal biopsy if one is really paranoid about getting a post-biopsy infection, though the latter would require general anesthesia, which has its own set of risks.
I thought the need for this had been settled a couple of years ago. How long does it take for sensible preventive practices to become routine? (A link to a blog post I remember reading here a couple of years ago appears in the “related” section above.)
Doug and Walter:
(1) The “routine” use of rectal swabs prior to prostate biopsy has never been formally approved by any organization that I am aware of. It is done routinely at some centers where there are known to be high risks for certain types of unusual organisms that are not sensitive to fluoroquinolone antibiotics like ciprofloxacin (Cipro).
(2) While there is increasing used of “shots” of drugs like gentamicin prior to prostate biopsy, this is also not “routine”, and making routine use of such drugs in patients who don’t actually need such injections is really not a very good idea, since it increases the probability of widespread gentamicin-resistant organisms (which then makes a very useful drug much less useful).
(3) An AUA-approved white paper on prostate biopsy discusses the paper by Taylor et al. and states that: “Rectal swabs have been used to assess rectal flora prior to prostate biopsy, as mentioned previously, and indicate a prevalence of about 22% of men harboring fluoroquinolone resistant bacteria. However, it remains undetermined if pre-procedural assessment of rectal flora with rectal swabs significantly reduces the number of infectious complications following prostate biopsy. Taylor and colleagues targeted specific antimicrobial prophylaxis based on rectal swab results. These authors were able to show a reduction in post-prostate biopsy infections from 2.6% to 0% and a cost savings per infectious complication averted. Despite the study’s limitations (single center, non-randomized, small cohort of patients), its findings recommend the need for further study of antimicrobial prophylaxis based on the results of pre-procedure rectal swabs to reduce the number of infectious complications.” In other words, there is no definitive recommendation for the routine use of rectal swabs.
(4) The use of transperitoneal biopsies is also associated with a significant risk for infectious complications (albeit lower than the risk associated with the use of transrectal biopsies). Arguably, from an individual patient perspective, that risk is high enough that a peritoneal swab prior to biopsy might also be a good idea — but I don’t believe anyone has done a large enough study to validate this concept.
It may take quite a while to resolve an issue like this because it is a good deal more complex than it may seem to be at face value. The 22% risk reported by Taylor et al. refers exclusively to their institution. It could easily be higher at some institutions and much, much lower at others. Currently, policies are developed by an infection control committee at individual institutions like hospitals, but what an individual community urology practice may or may not do is less well-defined.
Sitemaster,
Thank you again for posting this article and allowing this discussion of the risk of infection from TRUS prostate biopsies and potential ways to prevent it, which should encourage patients to do their own homework on the subject and be able to ask the right questions when planning for their own prostate biopsy.