Evaluation of antibiotic resistance to orally administrable antibiotics in staphylococcal bone and joint infections in one of the largest university hospitals in Germany: is there a role for fusidic acid?

Bone and joint infections (BJIs) are often difficult to treat. Staphylococcus spp. is the major pathogen causing these infections, which is often associated with biofilm formation on prosthetic materials. Therapeutic measures are complex, ranging from surgical intervention to initial intravenous and supportive long-term oral antibiotic therapy. The options for oral antimicrobial therapy are limited, mainly due to the resistance profile of the causative pathogen and the unfavourable pharmacodynamic and pharmacokinetic properties of most antibiotics in biofilm. Data analysis over a 5-year period was performed on staphylococci isolated from BJI patients in the Orthopaedic Department of the University Hospital Heidelberg (Heidelberg, Germany) to assess the plausibility of fusidic acid (FA)-based alternative oral treatment regimens. Six percent of BJIs were caused by meticillin-resistant Staphylococcus aureus (MRSA), and multiresistance was common. Over 75% of MRSA in BJIs were resistant to the commonly used rifampicin (RIF)-based combinations. Resistance to FA-based combinations was high. However, over 80% were susceptible to the combination RIF+FA. In coagulase-negative staphylococci, resistance to RIF-based combinations was similar to FA-based combinations. Almost two-thirds of the isolates tested were susceptible to RIF+FA. These data suggest FA as a possible option as a substitution for RIF or as a combination companion in case of resistance or unavailability.