Aspects of the microbe: host relationship in staphylococcal hematogenous osteomyelitis

Novel Technology to study co-evolution of humans and Staphylococcus aureus: consequences for interpreting the biology of colonisation and infection

Human nasal carriage of Staphylococcus aureus is a textbook example of an apparently neutral interaction between humans and a bacterial species that can still lead to (severe) opportunistic infections. The co-evolutionary aspects of this interaction are slowly surfacing, facilitated by the emergence of a diversity of diagnostic, epidemiological and molecular research tools. Basic microbiology has helped define persistent vs. non-carriage and the genotype of both host and guest has been explored in search of genetic markers for bacterial persistence. This chapter summarises the current state of affairs relating to artificial human colonisation studies with S. aureus, large-scale human cohort studies and innovative assessment of the humoral immune status of (non-)nasal carriers. These experimental approaches have recently assisted in identifying bacterial and human determinants and risk factors for staphylococcal carriage. Further refinement of the model by describing the interactions between S. aureus and its human host in molecular detail is important since it may pinpoint novel anti-infectious strategies.

Chronic osteomyelitis in children: Shriners Hospital Honolulu experience

Chronic osteomyelitis incidence and severity in 55 hospitalized Pacific Island children between 1990 and 2002 were compared with the expected incidence and reports in the literature. Of these 55 cases, 87% were from Polynesia/Micronesia. The average length of hospital stay was 104 days. Staphylococcus aureus was cultured in 64% of the cases with 43% of those being methicillin resistant S. aureus. A total of 111 bones were involved. Average antibiotic treatment was 135 days. Each case required an average of 1.3 irrigations/debridements and 45% required a sequestrectomy. Ninety-two percent had elevated erythrocyte sedimentation rate on admission. Sixty-nine percent of the cases involved metaphyseal, diaphyseal and epiphyseal segments of the bone and 29% were multifocal. Results indicate that Pacific Island children have a higher incidence and increased severity of osteomyelitis when compared with non-Pacific Island children in the literature, requiring a high suspicion for multifocal osteomyelitis, extensive bone involvement, S. aureus positive cultures and a longer period of antibiotic treatment.