Antibiotic resistance in Staphylococcus aureus and Staphylococcus epidermidis clinical isolates from implant orthopedic infections.

In the last decade the rising phenomenon of resistance to most common antibiotic drugs among staphylococcal clinical isolates has been a reason for serious concern and alarm. The present study investigated the prevalence of antibiotic resistance within a large microbial collection including 530 clinical strains of S. aureus and 408 strains of S. epidermidis to a panel of 16 different drugs. All strains were isolated from orthopedic infections, either associated or non-associated with implant materials. Interestingly, our data show that the profile of the prevalence of antibiotic resistance within the two species of pathogens is extremely similar for the vast majority of the drugs screened. The only statistically significant variations in prevalence concerned, in order of relevance, the following 5 out of 16 antibiotics: sulfamethoxazole (in combination with trimethoprim), erythromycin, and, to a lesser extent, oxacillin, imipenem, and clindamycin. In the case of Staphylococcus aureus, the isolates associated to implant materials were found more frequently resistant to all 4 aminoglycosides screened as well as to ciprofloxacin.