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Avoiding Urologic Surgery Infections

January 05 2009

An AUA-sponsored panel has developed a “Best Practice Statement” to guide antimicrobial prophylaxis.

The Best Practice Statement on Urologic Surgery Antimicrobial Prophylaxis was developed by the American Urological Association (AUA) and published in the April issue of the Journal of Urology (2008; 179:1379-1390). Corrected tables, which added some agents not included in the original publication and provided some clarifications, were published in the November issue of the Journal of Urology (2008;180:2262-2263). Additionally, the revised table was published in the November issue of AUANews (vol. 13, issue 11, 2008). The document is available online at the AUA Web site at www.auanet.org/content/guidelines-and-quality-care/clinical-guidelines/main-reports/antimicroprop08.pdf, accessed October 22, 2008.

PERIPROCEDURAL INFECTIONS are an important health care concern. Surgical-site infections occur after 5% of clean extra-abdominal procedures and are even more frequent after intra-abdominal operations. UTIs are the most common form of nosocomial infections. Despite clear demonstrations that appropriate antimicrobial prophylaxis reduces the incidence of surgical-site infections and postoperative UTIs, there is wide variation in practice. Standardizing antimicrobial prophylaxis and promulgating its proper application will improve patient care and reduce costs. Additionally, several national groups as well as the Centers for Medicare and Medicaid Services have requested specialty-specific recommendations for periprocedural antimicrobial prophylaxis to assist in the creation of pay-for-performance measures.

In response to these patient and organizational needs, the American Urological Association (AUA) convened a panel of experts and issued its Best Practice Statement on Urologic Surgery Antimicrobial Prophylaxis. Because of insufficient information to base recommendations solely on literature meta-analyses, the panel reviewed existing data supplemented by the members' expert opinions. Levels of evidence were assigned to the supporting literature, ranging from randomized trials and meta-analyses of randomized trials to case series and expert opinion, to clarify the strength of the recommendations.

Five principles

In preparing the statement, the panel identified five principles to guide antimicrobial prophylaxis in patients undergoing surgery.

1. “Surgical antimicrobial prophylaxis is the periprocedural systemic administration of an antimicrobial agent intended to reduce the risk of postprocedural local and systemic infections.”

Surgical antimicrobial prophylaxis is an important and easily modifiable component of a regimen to prevent periprocedural infection. Other measures for preventing infections include hand washing, sterile preparation of the operative field, and meticulous surgical technique. Measures in common use, but with doubtful efficacy based on recent data, include antiseptic bathing, mechanical bowel preparation, preoperative hair removal, and double gloving.

2. “The potential benefit of surgical antimicrobial prophylaxis is determined by three considerations: patient-related factors (ability of the host to respond to bacterial invasion), procedural factors (likelihood of bacterial invasion at the operative site), and the potential morbidity of infection.”

Factors that indicate an increased risk of periprocedural infection are a component of several of the panel's recommendations. The six risk factors that impair defense mechanisms are advanced age, anatomic anomalies of the urinary tract, poor nutritional status, smoking, chronic corticosteroid use, and immunodeficiency. The four risk factors that increase local bacterial concentration and/or the spectrum of flora are externalized catheters, colonized endogenous/exogenous material, distant coexistent infection, and prolonged hospitalization.

3. “Surgical antimicrobial prophylaxis is recommended only when the potential benefit exceeds the risks and anticipated financial, public-health, and personal-health costs.”

Surgical-site infections are associated with worse patient outcomes and increased costs. Appropriate prophylaxis reduces costs, and inappropriate (inadequate or excessive) prophylaxis increases costs. Financial costs include the expense of drugs and their administration and the expense of treating adverse outcomes. Personal-health costs are affected by such incidents as allergic reactions and antimicrobial-associated superinfections. Public-health costs include the induction of bacterial resistance in the community.

4. “The antimicrobial agent used for prophylaxis should be effective against the disease-relevant bacterial flora characteristic of the operative site. Cost, convenience, and safety of the agent also should be considered.”

A number of agents are listed in the panel's recommendations, and for most procedures, there are several alternatives. Some agents were chosen based on data from randomized trials, while others were selected for their activity against the pertinent organisms in the absence of randomized trials. Cephalosporins, fluoroquinolones, and aminoglycosides are particularly useful for surgical prophylaxis in urologic procedures because these agents have a long half-life, include inexpensive generic formulations, and are rarely associated with severe allergic reactions. Fluoroquinolones and aminoglycosides can be used safely in patients with beta-lactam allergy. Although rarely considered for prophylaxis outside of urologic surgery, fluoroquinolone use in urology is supported by four randomized trials comparing oral ciprofloxacin vs. IV cephalosporins. The trials involved a total of 345 patients undergoing a variety of endoscopic procedures. The incidence of postoperative bacteriuria was not different between the groups, and the costs in the ciprofloxacin group were lower, owing to reduced administration costs.

5. “The duration of surgical antimicrobial prophylaxis should extend throughout the period in which bacterial invasion is facilitated and/or is likely to establish an infection.” The initial dose of the antimicrobial agent should begin within 60 minutes of the surgical incision (120 minutes for IV fluoroquinolones and vancomycin). In general, prophylaxis for urologic surgery should be discontinued within 24 hours, and in many cases, a single dose is appropriate. Although common practice has been to administer agents longer when prosthetic material is implanted or tubes are inserted, there is no evidence that duration of therapy greater than 24 hours is useful. There are a few caveats to note, however. If there is an existing UTI, the urine should be sterilized with a full course of antimicrobial treatment prior to surgery. This is oftentimes not possible, so antimicrobials should be administered to at least suppress the bacterial count. In such cases, the antimicrobials are being used for treatment rather than prophylaxis. Many urologists are accustomed to administering an antimicrobial agent on removal of an externalized catheter. This is distinct from periprocedural antimicrobial prophylaxis and again is therapeutic rather than prophylactic. Such treatment is intended to prevent progression to clinical infection since the urine may be colonized owing to the external catheter. The duration of treatment in such cases is uncertain and depends on risk factors, the duration of catheterization, and the potential morbidity of infection. If urine sterility has been documented prior to catheter removal, antimicrobial treatment is not required. Alternatively, culture-directed agents can be used.

Recommendations

The most recent American Heart Association guidelines for the prevention of infectious endocarditis no longer recommend antimicrobial prophylaxis for genitourinary procedures solely to prevent infectious endocarditis. Similarly, guidelines published by the AUA and the American Academy of Orthopaedic Surgeons recommend that antimicrobial prophylaxis is not indicated for urologic patients based on the insertion or presence of orthopedic pins, plates, and screws. Antimicrobial prophylaxis is recommended, however, for some urologic patients with total joint replacements if there are both an increased risk of joint infection and increased risk of bacteremia from the urologic procedure. The risk of joint infection is elevated during the first two years after joint replacement and in replacement patients with such comorbidities as immunosuppression, prior joint infection, inflammatory arthropathies, diabetes mellitus, malignancy, malnourishment, or HIV infection. Procedures carrying an increased risk of bacteremia include any stone procedure, any bowel surgery, transrectal prostate biopsy, or entry into urinary tract in patient with increased risk of UTI. Appropriate agents would include oral fluoroquinolones or ampicillin (or vancomycin) plus gentamicin. In the setting of either cardiac valvular disease or total joint replacement, antimicrobial prophylaxis might be appropriate based on consideration of the patient and the urologic procedure, regardless of the cardiac or orthopedic conditions.

The antimicrobial prophylaxis recommendations are summarized in several tables in the Best Practice Statement. Justifications for the recommendations, including indication of the levels of evidence underlying the recommendations, are provided in the text. The key table is reproduced below (Table 1) and has been mailed to all members of the AUA.

Urologists can use these recommendations as a guide to efficacious, safe, and cost-effective administration of periprocedural antimicrobial prophylaxis. In the end, however, guidelines such as these are only a good starting point, as management of an individual patient requires consideration of not only these guidelines but also evaluation of the specific clinical circumstances.

Dr. Wolf is the David A. Bloom Professor of Urology and director of the Division of Minimally Invasive Urology, Department of Urology, University of Michigan Medical School, in Ann Arbor. He serves as vice-chair of the American Urological Association (AUA) Practice Guidelines Committee and chair of the AUA Urologic Surgery Antimicrobial Prophylaxis Best Practice Statement Panel. Other members of the panel included Carol J. Bennett, MD; Roger R. Dmochowski, MD; Brent K. Hollenbeck, MD, MS; Margaret S. Pearle, MD, PhD; and Anthony J. Schaeffer, MD.

Table 1.

Procedure	Prophylaxis Indicated	Antimicrobial(s) of Choice	Alternative Antimicrobial(s)
Prophylaxis for Lower Tract Instrumentation
Removal of external urinary catheter, cystography, urodynamic study, or simple cystourethroscopy	If risk factors	- Fluoroquinolone - Trimethoprim-sulfamethoxazole	- Aminoglycoside (Aztreonam) ± ampicillin - 1^st/2^nd gen. cephalosporin - Amoxicillin/Clavulanate
Cystourethroscopy with manipulation	All	- Fluoroquinolone - Trimethoprim-sulfamethoxazole	- Aminoglycoside (Aztreonam) ± ampicillin - 1^st/2^nd gen. cephalosporin - Amoxicillin/Clavulanate
Prostate brachy- or cryotherapy	Uncertain	- 1^st gen. gephalosporin	- Clindamycin
Transrectal prostate biopsy	All	- Fluoroquinolone - 2^nd/3^rd gen. cephalosporin	- Aminoglycoside (Aztreonam) + metronidazole or clindamycin
Prophylaxis for Upper Tract Instrumentation
Shock-wave lithotripsy and ureteroscopy	All	- Fluoroquinolone - Trimethoprim-sulfamethoxazole	- Aminoglycoside (Aztreonam) ± ampicillin - 1^st/2^nd gen. cephalosporin - Amoxicillin/Clavulanate
Percutaneous renal surgery	All	- 1^st/2^nd gen. cephalosporin, - Aminoglycoside (Aztreonam) + metronidazole or clindamycin	- Ampicillin/Sulbactam - Fluoroquinolone
Prophylaxis for Open or Laparoscopic Surgery
Vaginal surgery (includes urethral sling procedures) and surgery entering the urinary tract	All	- 1^st/2^nd gen. cephalosporin, - Aminoglycoside (Aztreonam) + metronidazole or clindamycin	- Ampicillin/Sulbactam - Fluoroquinolone
Surgery without entering urinary tract	If risk factors	- 1^st gen. cephalosporin (single dose)	- Clindamycin (single dose)
Surgery involving intestine	All	- 2^nd/3^rd gen. cephalosporin, - Aminoglycoside (Aztreonam) + metronidazole or clindamycin	- Ampicillin/Sulbactam - Ticarcillin/Clavulanate - Piperacillin/Tazobactam - Fluoroquinolone
Surgery involving implanted prosthesis	All	- Aminoglycoside (Aztreonam) + 1^st/2^nd gen. cephalosporin or vancomycin	- Ampicillin/Sulbactam - Ticarcillin/Clavulanate - Piperacillin/Tazobactam