Background: At present in Japan, there are neither reports on antibiotic prophylaxis regardless of underlying diseases nor precise guidelines on prophylactic antibiotics in orthopedic surgery. Therefore, the preventive effect of antimicrobial agents on surgical site infection (SSI) after clean orthopedic surgery was studied to control the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in our ward and to reduce SSI caused by MRSA.
Methods: Regardless of the type of operation or underlying disease, a regimen of prophylaxis that is of shorter duration than before was conducted in 419 patients admitted to our orthopedic ward (one ward) and who underwent clean orthopedic surgery between 2001 and 2002.
Results: The annual usage of beta-lactam antibiotics in the ward decreased by 960.9 g, the isolation rate of MRSA in the ward decreased to 50% (the lowest isolation rate in the past 4 years), and SSIs caused by MRSA were found in 3 of 419 (0.71%) patients in one year compared with 6 of 470 (1.28%) during the previous year. Comparison of two antibiotics revealed that SSI caused by MRSA did not occur in any of the 187 patients receiving sulbactam/ampicillin as prophylaxis but did occur in 1.29% (3/232) patients receiving cefazolin. Concerning all SSIs caused by any organisms, they occurred in 0.53% of patients receiving sulbactam/ampicillin and in 2.16% of patients receiving cefazolin. The difference in the SSI rates between the two groups was not statistically significant.
Conclusions: Although there is statistically no significant difference in the incidence of SSI caused by MRSA, we were able to decrease the isolation rates of MRSA and prevent MRSA from spreading owing to the reduced antibiotic usage in this study. Sulbactam/ampicillin can be recommended, as well as cefazolin, for antibiotic prophylaxis in clean orthopedic surgery.