Tolerant Staphylococcus aureus causing vertebral osteomyelitis

Abstract

Vertebral osteomyelitis due to S. aureus was suppressed but not cured by optimal therapy with nafcillin sodium; cure eventually was achieved by treatment with cefazolin sodium and gentamicin sulfate. This in vivo result correlated with in vitro observations that showed that the infecting organism was inhibited but not killed by prolonged incubation with nafcillin or cefazolin; killing was readily achieved in vitro by adding subinhibitory concentrations of gentamicin. Bacterial tolerance in this case appeared to be responsible for the failure of vertebral osteomyelitis to be cured by accepted therapy with .beta.-lactam antibiotics.