Antimicrobial prophylaxis, quinolone resistance and prostate biopsy safety

Guest post: Patrick Harris, Staff Specialist in Microbiology, Central Laboratory, Pathology Queensland, Brisbane

Overseas travel and prostate biopsies: a key risk-factor for infectious complications with multi-drug resistant bacteria

Given an ageing population and the current reliance upon PSA testing to screen for prostate cancer, patients are increasingly being referred for trans-rectal ultrasound (TRUS)-guided prostate biopsies.  Millions of these procedures are being performed annually around the world.  Although generally considered a low-risk procedure, increasing resistance to antibiotics may be tipping the risk-benefit balance in some patients. Infections, when they occur, are usually caused by bacteria that inhabit the bowel such as Escherichia coli.  Infectious complications are thought to occur in up to 6% of cases (depending on where in the world the procedure is done), and a proportion of these may be severe. Rates of bloodstream infection post TRUS-biopsy can range from 0.6-2%, with around 25% of these presenting with septic shock or requiring admission to intensive care.

Practice guidelines recommend the use of prophylactic antibiotics, such as a single dose of ciprofloxacin 500mg 1-2 hours prior to TRUS biopsy (eTG).  However, in many parts of the world resistance to fluoroquinolones in Gram negative uropathogens has reached alarming proportions.  Looking at studies reporting rates of quinolone resistance in urinary pathogens over the last 5 years, areas of high prevalence can be seen particularly in Asia and countries in Eastern Europe and the Mediterranean.

uropathogens

Resistance to fluoroquinolones in Gram-negative uropathogens: review of reported studies 2009-2015

So we can see that in many parts of the world, if a patient has a urinary infection there is a greater than 50% risk that the organisms are resistant to quinolones.  Furthermore we know that travel to these areas significantly increases your risk of carrying these resistant strains in your gastrointestinal tract – especially if antibiotics are also taken during this period

trans rectal prostate

Obviously rectal colonisation with such strains is a danger for any procedure introducing bowel flora (including resistant strains, enriched by ineffective prophylactic antibiotics that kill competing susceptible strains) into usually sterile sites.

So what should clinicians do? 

  • For anyone having a TRUS-guided biopsy, a history of travel (within 6 months) to an area endemic for high levels of antibiotic resistance (see map) or recent (within 3 months) quinolone use should be sought
  • If this is the case, the increased risk of infectious complications with a resistant organism should be considered and communicated
  • Additional pre-operative screening for resistant organisms may be necessary in consultation with an infectious disease physician or microbiologist.
  • Serious consideration should be given to avoiding or delaying the procedure or using non-rectal approaches (e.g. trans-perineal)

Local Hunter New England experience with post biopsy infection has been published recently.  Local bacterial resistance cumulative antibiograms for 2015 are under preparation.

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