Prosthesis culture 6 months after implantation and the effect of haematogenous seeding in a rat model.

The aim of this study was to investigate the role of haematogenous seeding in late prosthesis infection. In all, 45 male Wistar albino rats were divided into three equal groups. A small piece of silicone prosthesis was implanted into the scrotum of all rats under sterile condition and antibiotic prophylaxis. In the first group, all silicones were removed after 6 months without any complication and were cultured for bacterial growth. In the second group, a disc, which was saturated with Staphylococcus epidermidis, was inoculated subcutaneously in the legs of the rats in the 6th month, revealing a nodule formation 4-5 days after the inoculation and treated with an appropriate antibiotic after the nodule formation. In the third group, the same disc was inoculated, but all rats were treated immediately from the inoculation time onwards. The silicones of the second and third group were also removed at the end of the 6th month and were cultured to observe the bacterial growth. There was no evidence of prosthesis infection in any of the three groups. In the first group, three cultures were positive and revealed approximately 10 000 colonies of S. epidermidis in two and Proteus mirabilis in the remaining. Three and four cultures were positive in the second and third group, respectively. Low colonies of four different organisms (Escherichia coli, S. aureus, S. epidermidis, Pseudomonas aeruginosa) were identified in these cultures. There was no statistical significance of positive cultures in the three groups. Based on our results, there does not appear to be a true significance of haematogenous seeding on late prosthesis infection.