Contamination Of Bone Allografts: Analysis Of Incidence And Predisposing Factors

Abstract

We analysed the bacterial contamination of 1999 bone allografts retrieved from 200 cadaver donors under sterile operating conditions. The effect of various factors on the relative risk of contamination was estimated using a multiple logistic regression model. Organisms of low pathogenicity were cultured from 50% of the grafts and of high pathogenicity from 3%. The risk of contamination with low pathogenic organisms (mainly skin commensals) increased by a factor of 1.6 for each member added to the procurement team. The risk of contamination with high pathogenic organisms (mainly contaminants from the gastrointestinal tract) was 3.4 times higher in donors with a traumatic cause of death and 5.2 times higher in those with a positive blood culture. Preceding organ procurement did not significantly influence the risk of contamination. Rinsing the graft with an antibiotic solution was not an effective decontamination method. The major source of contamination is exogenous and is strongly influenced by the procurement team. Contamination from endogenous sources can be controlled by donor selection. We discuss methods that can be used to decrease contamination and the rate of discarding of bone allografts.

Cadaveric allograft microbiology

“…However, 12 of our bone allografts grew Streptococcus. Deijkers et al [4] divided contaminating organisms into low and high pathogenicity. They considered organisms of low pathogenicity to be skin commensals.…”

The real contamination of femoral head allografts washed with pulse lavage

“…It is important that the graft is packed immediately after bacterial screening and touched as little as possible by gloves. Contamination may arise from the operation team, environment or donor (Veen 1994, Deijkers et al 1997, Sommerville et al 2000. However, the specimen may also become contaminated in the laboratory during preparation for culture (Farrington et al 1998).…”

“…The contamination percentage has varied between 3-40% depending on the tissue taken and the screening method used (Veen 1994, Deijkers et al 1997, Sommerville et al 2000. In one report, the contamination of femoral heads was 22% (Sommerville et al 2000).…”

Cortical allograft as a vehicle for antibiotic delivery

“…There have been many reports on contamination of bone allografts during the process of procurement (Deijkers et al 1997, Journeaux et al 1999, Hirn et al 2001). Rinsing of a large bone allograft with an antibiotic solution after removal from the donor does not eradicate microorganisms efficiently (Deijkers et al 1997, Hirn et al 2001.…”

“…Rinsing of a large bone allograft with an antibiotic solution after removal from the donor does not eradicate microorganisms efficiently (Deijkers et al 1997, Hirn et al 2001. The exposure time may be too short for the antibiotics to be effective (Deijkers et al 1997).…”