Contaminated rabbit patellar tendon grafts. In vivo analysis of disinfecting methods.

In Part 1 of our study, 40 central-third bone-patellar tendon-bone grafts were harvested from 20 adult California White rabbits under strict sterile conditions. Ten grafts were placed directly into a thioglycolate broth, incubated, and subcultured; no growth was noted in any specimen. The next 6 grafts were contaminated 20 seconds each with 2 different species of coagulase-negative staphylococci. Organisms were grown with cultures obtained from an operating room floor during anterior cruciate ligament reconstruction. Marked growth of both species was noted in all 6 grafts within 24 hours. A subsequent 3 series of 8 grafts each were harvested sterilely, contaminated as described above, and soaked in 1 of 3 solutions 30 minutes before culture. Both 10% povidone-iodine and a triple-antibiotic solution (gentamicin, clindamycin, polymyxin) were 100% ineffective as both organisms grew; 4% chlorhexidine gluconate effectively decontaminated 8 grafts in all cases. Part 2 involved contamination of harvested grafts with 5 common, virulent organisms: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterococcus faecalis. Elimination of all except Klebsiella pneumoniae was successful with 4% chlorhexidine gluconate alone for 8 grafts. Using a triple-antibiotic solution after chlorhexidine gluconate in 6 grafts eliminated this organism also.