Internalization of Bacteria by Osteoblasts in a Patient with Recurrent, Long-Term Osteomyelitis: A Case Report

O steomyelitis, an infection of bone that can be acute, subacute, or chronic with sporadic recurrence, can result in prolonged and expensive treatment1,2. Treatment strategies, which usually depend on the stage of the disease at the time of diagnosis, often include debridement of the infected area, soft-tissue coverage, and subsequent long periods of antibiotic therapy. With the increasing development of antibiotic-resistant bacteria, antibiotic therapy has become even more problematic. Recent research has greatly advanced our understanding of the pathobiology of osteomyelitis. Studies by one of us (W.K.R.) and colleagues demonstrated that live and dead Staphylococcus aureus, the primary pathogen associated with osteomyelitis, can be internalized in vitro by osteoblasts isolated from calvariae of sixteen-day-old chick embryos3,4. Bacteria were identified both within vesicles and free in the osteoblast cytoplasm. This demonstration that bacteria can be sequestered from the host immune system within the osteoblast cytoplasm has been a breakthrough in our understanding of osteomyelitis as it provides an hypothesis to explain the recurrence of this condition. To our knowledge, demonstration of internalization of bacteria by osteoblasts in vivo has not been reported. The purpose of the present study was to examine osteoblasts in surgical bone specimens from a patient who presented with chronic osteomyelitis that had been recurrent over a period of many years. Before surgery, the patient was informed that data concerning this case would be submitted for publication following special morphologic analysis for the presence of intracellular bacteria in bone cells. A seventy-three-year-old man presented for evaluation of a draining lesion, of three month's duration, that was located on the middle part of the lateral aspect of the leg. The patient stated that he had been diagnosed with osteomyelitis of the fibula at the age of seven years and had been …