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758 Preoperative surveillance for methicillin-resistant Staphylococcus aureus nasal colonization does not identify a majority of patients with postoperative staphylococcal infections in a Veterans Affairs hospital

Sunday, March 21, 2010: 11:45 AM
Centennial III-IV (Hyatt Regency Atlanta)
Andrew M. Ibrahim, BS , Cleveland VA Medical Center, Cleveland, OH
Brook Watts, MD, MS , Cleveland VA Med Center, Cleveland, OH
Usha Stiefel, MD , Cleveland VA Medical Center, Cleveland, OH
Curtis J. Donskey , Cleveland VA Medical Center, Cleveland, OH

Background:

The Department of Veterans Affairs methicillin-resistant Staphylococcus aureus (MRSA) Prevention Initiative requires routine surveillance for nares carriage of MRSA on admission, ward transfer, and discharge. These data could potentially be used to identify surgical patients at risk for postoperative staphylococcal infections who might benefit from peri-operative decolonization.

Objective:

To test the hypothesis that pre-operative surveillance for MRSA nares colonization will identify a majority of patients who develop postoperative S. aureus infections.

Methods:

We performed a retrospective review of all clean surgical procedures at a VA hospital from 1/07 through 3/09 and identified cases of postoperative S. aureus infection. Infections were classified as surgical site infections (superficial incisional, deep incisional, and organ/space) or non-surgical site infections and as MRSA or methicillin-susceptible S. aureus (MSSA) infections. For MRSA infections, the proportions with positive versus negative pre-operative nares MRSA results were determined.

Results:

Of 5528 total clean surgical procedures, 37 (0.7%) were complicated by postoperative S. aureus infections, including 17 MSSA and 20 MRSA infections. Five of the 20 (25%) patients with MRSA infections did not have preoperative nares screening for MRSA. Of the 15 patients with MRSA postoperative infections and preoperative screening, only 6 (40%) had positive preoperative nares screening results. Thirteen of 20 (65%) MRSA infections and 14 of 17 (82%) of MSSA infections were surgical site infections.

Conclusions:

Preoperative screening for MRSA nares colonization identified only a minority of patients with subsequent postoperative S. aureus infections in our VA hospital. Preoperative screening for both MRSA and MSSA may be indicated to identify patients who might benefit from decolonization. Further research is needed to determine if development of postoperative MRSA infections despite negative preoperative nares results is due to colonization at sites other than the nares or to acquisition of MRSA during or after surgery.