Princeton, NJ—The antibiotic prescriptions pharmacists fill for some presurgical patients may no longer have the desired effect.

A new study in Infection Control and Hospital Epidemiology found that prophylactic antibiotics are becoming less effective at preventing surgical-site infections following colorectal surgery. Researchers from Princeton University and the Center for Disease Dynamics, Economics & Policy came to that conclusion after a systematic review of available literature.

The effectiveness of antibiotic prophylaxis in preventing infection following appendectomy, cesarean section, and transrectal prostate biopsy (TRPB) procedures appeared statistically unchanged, the study team suggests, although this analysis was challenged by small sample size.

Included in the review were 74 randomized control trials—nine for appendectomy, 11 for cesarean section, 15 for TRPB, and 39 for colorectal surgery. In terms of related infections, the overall proportion was 3% for appendectomy, 4.1% for cesarean section, and 1.2% for TRPB, and these did not change significantly overtime.

That was not the case for colorectal procedures, however. Between 1980 and 2005, the researchers report, the overall infection rate for colorectal procedures and all prophylactic drug treatments was 14%. Yet, during that time, a statistically significant increase in infection rate occurred, rising from about 10% in 1980 to about 25% in 2005.

The study team notes that the trend remained significant even after adjusting for the type of surgery and antibiotic used—cefoxitin, cefotetan, and cefazolin plus metronidazole.
“There were over 300,000 colorectal surgeries performed in the United States last year,” explained coauthor Ramanan Laxminarayan, PhD, MPH, CDDEP director. “An increase in infection rates and a decline in the efficacy of prophylaxis may be a reflection of growing antibiotic resistance, which needs to be tackled urgently.”

Study authors suggest that rising antibiotic resistance could be reducing the effectiveness of antibiotics in preventing postoperative infections.

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