[Microbiological Diagnosis of Implant-associated Infections : Retrospective Analysis of 133 Patients in an Arthroplasty Center]

Background: Because standardized microbiological cultures of puncture fluids and tissue samples often do not provide pathogen detection in implant-associated infections, sonication and polymerase chain reaction (PCR) are used additionally today.

Objectives: Pathogen spectra and previous microbiological standards are examined for agreement of results using the new methods sonication and PCR.

Materials And Methods: In this descriptive, retrospective observational study, we evaluated the data of 133 patients in whom a joint prosthesis, osteosynthesis material or a spacer was removed during revision surgery with suspected implant-associated infection and sent for sonication.

Results: Pathogen detection was achieved by culture of peri-implant material in 40.1% and by sonication in 42.5%. In each case, coagulase-negative staphylococci were detected most frequently. Overall, the results were consistent in 71.7% of cases. In the discrepant cases, more anaerobes could be detected by sonication, especially for osteosynthesis material and knee prostheses. PCR analyses in 21 cases showed pathogen detection in 14.3% and agreement with the results of peri-implant tissue culture and sonication in 57.1% and 66.7%, respectively.

Conclusions: The present results indicate a gain in sensitivity of sonication, especially for anaerobes that are difficult to grow, and a gain in specificity through sonication. PCR analyses should be reserved for specific questions.