Pre-Op Urine Screening Not Necessary

Routine preoperative urine screening offers no clinical benefit, according to a large study published Dec. 12 in JAMA Surgery. Treating asymptomatic bacteriuria detected by screening does not cut the risk for postoperative infections, including UTI and SSI, the authors say.

"This study is the largest and most robust investigation into urine culture screening to date," write the authors led by Jaime Gallegos Salazar, M.D., from the VA Boston Healthcare System in Massachusetts. "It provides strong evidence that preoperative screening may not be valuable and should be discontinued as routine clinical practice."

Given concerns about antibiotic stewardship, the Choosing Wisely campaign recommends not treating asymptomatic bacteriuria (ASB) in most circumstances. However, surgeons installing new hardware often feel compelled to treat any colonizing organism in the hopes of preventing dangerous postoperative infections, such as prosthetic joint infections. More recently, the Infectious Diseases Society of America's 2018 AMB guidelines also recommend against preoperative screening, but lacked high-quality, supporting data.

The Veterans Affairs (VA) researchers used data from 68,265 U.S. veterans (96.2 percent men; mean age, 64.6 years) who underwent cardiac, orthopedic, or vascular surgical procedures at 109 U.S. Department of Veterans Affairs health care system facilities (Oct. 1, 2008, to Sept. 30, 2013). Associations between detection and treatment of preoperative ASB and postoperative outcomes, including surgical site infection (SSI) and urinary tract infection (UTI), were evaluated. Facility and/or surgeon practice guided the decision to screen with a preoperative urine culture. A positive culture was defined as 105 or more colony-forming units of any bacterial organism isolated.

The researchers found that preoperative urine cultures were performed in 26 percent of patients. Positive results occurred in 4.3 percent of screened patients, of which the vast majority (81.7 percent) were classified as having asymptomatic bacteriuria (ASB). Odds of SSI and UTI were similar for patients with and without ASB, even when adjusting for age, American Society of Anesthesiologists class, smoking status, race/ethnicity, sex, and diabetes status. Further, antimicrobial therapy targeted against the asymptomatic uropathogen was not associated with improvement in SSI or UTI.

Among patients prosthetic joint infection, there were no cases where the ASB organism matched the organism found in the joint infection. ASB organisms matched a postoperative wound culture (Staphylococcus aureus) in just cases.

"These findings will be greeted with joy by infectious diseases physicians far and wide," wrote Barbara Trautner, M.D., Ph.D., from Baylor College of Medicine in Houston, Texas, in an accompanying editorial. "Eliminating routine preoperative urine cultures will reduce the number of positive urine culture results in asymptomatic patients, in turn reducing unnecessary antibiotic use."

Takeaway: Routine preoperative urine culture screening should be discontinued among patients undergoing cardiac, orthopedic, or vascular surgical procedures.