Activity of commonly used antimicrobial prophylaxis regimens against pathogens causing coronary artery bypass graft and arthroplasty surgical site infections in the United States, 2006-2009.

BACKGROUND

Coronary artery bypass graft (CABG) and primary arthroplasty surgical site infection (SSI) rates are declining slower than other healthcare-associated infection rates. We examined antimicrobial prophylaxis (AMP) regimens used for these operations and compared their spectrum of activity against reported SSI pathogens.

METHODS

Pathogen distributions of CABG and hip/knee arthroplasty complex SSIs (deep and organ/space) reported to the National Healthcare Safety Network (NHSN) from 2006 through 2009 and AMP regimens (same procedures and time period) reported to the Surgical Care Improvement Project (SCIP) were analyzed. Regimens were categorized as standard (cefazolin or cefuroxime), β-lactam allergy (vancomycin or clindamycin with or without an aminoglycoside), and extended spectrum (vancomycin and/or an aminoglycoside with cefazolin or cefuroxime). AMP activity of each regimen was predicted on the basis of pathogen susceptibility reports and published spectra of antimicrobial activity.

RESULTS

There were 6,263 CABG and arthroplasty complex SSIs reported (680,489 procedures; 880 NHSN hospitals). Among 6,574 pathogens reported, methicillin-sensitive Staphylococcus aureus (23%), methicillin-resistant S. aureus (18%), coagulase-negative staphylococci (17%), and Enterococcus species (7%) were most common. AMP regimens for 2,435,703 CABG and arthroplasty procedures from 3,330 SCIP hospitals were analyzed. The proportion of pathogens predictably susceptible to standard (used in 75% of procedures), β-lactam (12%), and extended-spectrum (8%) regimens was 41%-45%, 47%-96%, and 81%-96%, respectively.

CONCLUSION

Standard AMP, used in three-quarters of CABG and primary arthroplasty procedures, has inadequate activity against more than half of SSI pathogens reported. Alternative strategies may be needed to prevent SSIs caused by pathogens resistant to standard AMP regimens.