Switch from cefazolin to vancomycin resulted in reduced overall infections

In many hospitals, cefazolin is the antibiotic of choice as perioperative prophylaxis for patients undergoing total joint replacement procedures. At the 2011 annual meeting of the American Association of Hip and Knee Surgeons (AAHKS), however, Eric B. Smith, MD, of the Rothman Institute in Philadelphia, presented the results of a study indicating that using vancomycin resulted in both fewer methicillin-resistant Staphylococcus aureus (MRSA) infections and fewer overall infections.

Not only are periprosthetic joint infections (PJI) devastating complications, infections due to resistant organisms such as MRSA are more costly and more difficult to treat.

“We switched the perioperative prophylactic antibiotic from cefazolin to vancomycin in June 2008,” reported Dr. Smith. “Our hypothesis was that the number of overall infections and the number of MRSA infections would decrease.”

The retrospective study first identified all PJI requiring open irrigation and débridement (I & D) or resection arthroplasty from Jan. 1, 2006 through Dec. 31, 2010. The rate of infection in all primary procedures for the 29 months prior to the change in antibiotics was then compared to the same rate for the 31 months after the change.

Researchers identified 23 PJI among the 2,221 primary total hip and total knee procedures prior to the shift to vancomycin, for a total infection rate of 1.0 percent. Among the 2,815 primary total hip and total knee procedures performed after the change in antibiotics, however, there were just 14 PJI (0.5 percent) (P = 0.03).

“MRSA infections also decreased,” noted Dr. Smith, “from five (0.23 percent) to two (0.07 percent). In addition, the rate of coagulase negative Staphylococcus (including S. epidermidis and S. saprophyticus) also decreased significantly. There were no occurrences of vancomycin-resistant Enterococcus infections.”

When PJI did occur, they were easier to cure, he reported. “Our overall success rate for treating PJI remained constant. However, the success rate of treating PJI with open I & D (avoiding resection arthroplasty) increased from 22.2 percent to 76.9 percent (P = 0.002). This is a positive trend that may show that we are protecting patients from more virulent bacteria.”

On the other hand, the rate of both methicillin-sensitive S. aureus infections and Streptococcus (alpha and groups B/G) infections increased. As a result, Dr. Smith noted that further studies analyzing the use of vancomycin in combination with beta-lactam antibiotics may be beneficial.

Dr. Smith reported no conflicts of interest. His coauthors for “Is it time to include vancomycin for routine perioperative antibiotic prophylaxis in total joint replacement patients?” included Rachael Wynne, RN (no conflicts); Hans Liu (no conflicts); and Robert P. Good, MD (unpaid consultant for Stelkast, Inc.). The authors will present this study as Poster P193 at the 2012 AAOS Annual Meeting.

Download the final program and read the abstract: http://www.aahks.org/meetings/anmeet/pastanmeets/AM11FinalProgram.pdf (page 48)