STAPHYLOCOCCUS-EPIDERMIDIS PRODUCES A CELL-ASSOCIATED PROTEINACEOUS FRACTION WHICH CAUSES BONE-RESORPTION BY A PROSTANOID-INDEPENDENT MECHANISM - RELEVANCE TO THE TREATMENT OF INFECTED ORTHOPEDIC IMPLANTS
S. Meghji et al., STAPHYLOCOCCUS-EPIDERMIDIS PRODUCES A CELL-ASSOCIATED PROTEINACEOUS FRACTION WHICH CAUSES BONE-RESORPTION BY A PROSTANOID-INDEPENDENT MECHANISM - RELEVANCE TO THE TREATMENT OF INFECTED ORTHOPEDIC IMPLANTS, British journal of rheumatology, 36(9), 1997, pp. 957-963
Staphylococcus epidermidis is the, most commonly isolated coagulase-ne
gative staphylococcus from the skin, gut and upper respiratory tract.
Although it is less virulent than Staphylococcus aureus, it has emerge
d in recent years as an important causative agent of infections associ
ated with metal implants, prosthetic devices and i.v. lines. We have p
reviously demonstrated that a saline wash of S. aureus contained prote
ins which had potent bone-resorbing activity in vitro. The purpose of
this study was to determine whether gently washing S. epidermidis in s
aline also released osteolytically active proteins. The so-called surf
ace-associated material (SAM) eluted from S. epidermidis in saline was
able to induce osteolysis, and activity was heat and trypsin sensitiv
e, suggesting that the active component was proteinaceous. Fractionati
on studies have suggested that activity is due to a small number of ca
tionic proteins. This SAM-induced bone resorption was not inhibited by
the cycle-oxygenase inhibitor, indomethacin, or the 5-lipoxygenase in
hibitors BWA70C and MK886. However, it was partially inhibited by high
concentrations of interleukin-1 receptor antagonist and was completel
y blocked by a neutralizing antibody to tumour necrosis factor-alpha.
Thus, the SAM from this organism is a potent osteolytic agent which di
ffers from that of S. aureus SAM in not being inhibited by cyclo-oxyge
nase inhibitors. As adjunctive therapy is becoming necessary in infect
ious diseases, either as a result of the side-effects of antibiotics o
r their lack of efficacy, consideration should be given to the future
treatment of bone infections with staphylococci in the light of the di
fferent mechanisms of action of the surface proteins produced by these
bacteria.