Antibacterial effects of brand-name teicoplanin and generic products against clinical isolates of methicillin-resistant Staphylococcus aureus

Glycopeptide antibiotics, such as vancomycin and teicoplanin, have been used worldwide to treat infection caused by methicillin-resistant Staphylococcus aureus (MRSA). Generic teicoplanin products were manufactured by many companies in 2009. We investigated the susceptibility of 147 MRSA strains to brand-name teicoplanin (TEIC-1) and seven generic products (TEIC-2 to TEIC-8). The MIC90 of generic TEIC-5 and TEIC-7 was 8 μg/ml whereas that of TEIC-1 and other generic products was 4 μg/ml. The potency equivalent of generic TEIC-5 and TEIC-7 was lower than that of TEIC-1, and TEIC content (%) per potency equivalent (200 mg) in a vial of these two generic products varied greatly compared with the other products. Although the potency equivalent of the TEIC used in this study was within the range stipulated in the Japanese Pharmacopeia, these results showed that the potency equivalent and susceptibility of two of the seven generic products differed from that of TEIC-1. The predicted AUC0-72 value of those two generic products was 84-85% in comparison with that of TEIC-1. Among generic drugs, there may be products whose antimicrobial effect is not equal to that of the brand teicoplanin.