A double-blind comparative study of prophylactic antibiotic therapy in open heart surgery: penicillin G versus vancomycin.

A double-blind clinical study was carried out comparing the prophylactic effectivity of penicillin G with vancomycin in 113 adult patients undergoing open heart surgery. Eighty of these underwent valve replacement. A total of 14 of 52 penicillin-treated patients (26.9%) and 5 of 61 vancomycin-treated patients (8.2%) suffered from postoperative infection (0.005 less than p less than 0.02). Five patients in the penicillin group and none in the vancomycin group developed postoperative wound infection (0.01 less than p less than 0.02). No significant differences in blood culture and sepsis, tracheal culture and clinical respiratory tract infection, urine culture and clinical urinary tract infection, and colonization rate were found between the 2 groups. No cases of prosthetic valve endocarditis were diagnosed. Bacteriologic culture and resistance studies did not reveal significant changes concerning the resistance patterns; in particular, the emergence of a vancomycin-resistant strain of Staphylococcus albus was not seen. A decrease in the colonization rate with Staphylococcus albus from 53% in 1975 to 1977 to 34.6% and 31.1% in the penicillin and vancomycin groups, respectively, was found in the following 2 years.