Fluoroquinolone Use and Association with Fluoroquinolone-Resistance in Pre-Prostate Biopsy Stool Samples and
Post-Biopsy Infection
Angharad Webb, PharmD, BCPS, Scott Johns, PharmD, BCPS (AQ-ID), Joshua Fierer, MD
VA San Diego Healthcare System, San Diego, CA
UCSD Skaggs School of Pharmacy, San Diego, CA
• Prophylactic antibiotic: 750mg x1 dose of ciprofloxacin
• Stool collected on day of biopsy was screened for the
presence of ciprofloxacin-R E. coli using 4/µg/ml in
Maconkey’s agar
• Data collected from each patient included:
• Date of biopsy, presence of ciprofloxacin R,
presence of ESBL E. coli, fluoroquinolone usage in
the previous six months, type of fluoroquinolone
including formulation, length of therapy,
occurrence of post-biopsy infection
• Patients with ciprofloxacin-R were matched in a 1:1
ratio with patients who had a biopsy on the same day
but did not have ciprofloxacin R E. coli in feces.
• Study period: February 14, 2012-February 14, 2013
• Inclusion Criteria: All patients receiving a prostate
biopsy with stool culture during the study period
• Exclusion Criteria: Patients with multiple biopsies
• Chi square analysis was used to evaluate differences
between groups
• SPSS Statistical Analysis Software, version 20 was used
Association Between Fluoroquinolone Use and Resistance
• Fluoroquinolone use in the previous six months is not a
reliable predictor of fluoroquinolone R E. coli in the
• Stool culture is a reliable method for identifying
patients at risk for post-biopsy infection, but less than
10% of patients with resistant bacteria got infected
• The high rate of fluoroquinolone resistance despite a
lack fluoroquinolone use suggests patients are
acquiring resistant E. coli from the environment.
• Increasing rates of ESBL-producing organisms towards
the end of the study suggests an increasing prevalence
of these organisms and could mean that infections will
be more difficult to treat.
Prostate biopsies have been associated with various infectious
complications most commonly due to Escherichia coli (E. coli).
Ciprofloxacin is the prophylactic antibiotic of choice. Fluoroquinolone
resistance has been associated with increasing post-biopsy infection rates.
Our study was developed to evaluate fluoroquinolone usage and the
presence of ciprofloxacin-resistant E. coli and post-biopsy infection. Stool
cultures were obtained on all patients the day of biopsy and evaluated for
ciprofloxacin resistance. Patients with fluoroquinolone-resistance were
case-matched in a 1:1 ratio with patients who had a biopsy on the same
day over a one year period. 347 patients had a pre-biopsy stool culture. Of
these, 63 patients had ciprofloxacin-resistant E. coli. 49 patients were
case-matched with a patient without ciprofloxacin-resistant E. coli. No
significant difference was found in previous fluoroquinolone use between
the two groups (p=0.754). While limited by small sample size, there was
no statistically significant difference in history of fluoroquinolone use
(p=0.21). Four patients experienced a post-biopsy infection. Of these,
three did not have a history of fluoroquinolone use. Previous
fluoroquinolone use is not a reliable method for predicting
fluoroquinolone resistance in E. coli in the stool. Obtaining a stool culture
prior to biopsy remains the most effective method for screening for the
presence of ciprofloxacin resistance and thus for the risk of post-biopsy
• Trans-rectal ultrasound (TRUS) guided prostate biopsies
have been associated with infectious complications
including cystitis, pyelonephritis, prostatitis, and
• Escherichia coli (E. coli) is the most common pathogen
• AUA guidelines3 recommend a single dose of
ciprofloxacin as the prophylactic antibiotic of choice
• Increases in post-biopsy infection are unexplained;
however, increasing fluoroquinolone resistance (R) has
been suggested as a contributory factor2
• Increasing rates of Extended Spectrum Beta-Lactamaseproducing (ESBL) E. coli may also contribute to
increasing resistance and infection rates
• Prior fluoroquinolone use has been associated with
infection with fluoroquinolone resistant E. coli
• Highest correlations between colonization with resistant
bacteria and a history of fluoroquinolone usage occur
within 3-6 months prior4
• New antibiotic regimens have been proposed for
prophylaxis including fosfomycin5. However, further
research is needed to justify the cost-effectiveness of
these more expensive regimens.
• Due to increasing infection rates, our facility began
obtaining stool cultures the day of biopsy and testing
for ciprofloxacin resistance
347 patients with
prostate biopsy
1 patient excluded for
multiple biopsies
during study period
63 patients (+) cipro R
283 patients (-) cipro R
49 patients case matched based
on day of biopsy
Number of Patients
(+) Resistance
(-) Resistance
FQ Use
No FQ Use
FQ Use in Previous Six Months
Presence of ESBL E. coli:
• 5 patients included in final analysis
• 3 patients had no previous FQ use
• 2 patients had a history of FQ use
• 2 patients with an ESBL developed a post-biopsy
• 3/5 patients with an ESBL were cultured during the
last 2 months of the study period
Post-Biopsy Infection:
• 4 patients had a post-biopsy infection
• All infections were due to ciprofloxacin R E. coli
• Only 1 patient with a post-biopsy infection had a
history of FQ use
• Post-biopsy infections included:
• Cystitis (2)
• Prostatitis (2)
• Bacteremia (1)
• Additional patient demographic data:
• 49 patients case-matched
• 63 patients had cipro-R
• 14 excluded due to case-matching
• 6 patients had ESBL-producing isolates*
• 45 patients (13%) had a history of fluoroquinolone
• 4 patients experienced a post-biopsy infection
*One patient not included in final analysis due to case matching
• Prescription records were obtained using VA data.
Patients may have received fluoroquinolones from
outside sources
• During the prostate biopsy, lidocaine is used as a
topical anesthetic which may have some antibacterial
• The sample size of this study is comparable to previous
• Post-biopsy infection was consistently associated with
ciprofloxacin R, suggesting a need for other
prophylactic strategies
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from SEER-Medicare. J Urology. 2011;186:1830-4.
3. American Urological Association Education and Research. Best Practice Policy
Statement on Urologic Surgery Antimicrobial Prophylaxis 2012. Available at:
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fosfomycin as antimicrobial prophylaxis for patients undergoing transrectal
ultrasound-guided biopsy of the prostate. Urol Int. 2012;89(4):439-44.
6. Kaesbohrer A, Schroeter A, Tenhagen BA, et al. Emerging antimicrobial
resistance in commensal Escherichia coli with public health prevalence. Zoonoses
and Public Health. 2012; 59(Suppl 2): 158-65.
7. Williamson DA, Barrett LK, Rogers BA, et al. Infectious complications following
transrecetal-ultrasound (TRUS) guided prostate biopsy: new challenges in the era
of multi-drug resistant Escherichia coli. CID 2013 Advanced Access 3/26/2013.
8. Taylor S, Margolick J, Abughosh Z, et al. Ciprofloxacin resistance in the faecal
carriage of patients undergoing transrectal ultrasound guided prostate biopsy.
BJU International. 2013;1-8.
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resistance in human commensal bacteria. JID. 2009;200:390-8.
Special thanks to our microbiology laboratory for their
support with this project and assistance with collecting the
• Angharad Webb:
• Email: [email protected]
• Address: C/O Pharmacy Service 119
3350 La Jolla Village Drive
San Diego, CA 92122