Characterization Of Bacterial Communities In Suspected Prosthetic Joint Infections

Steadily increasing numbers of persons have received prosthetic joints to help relieve pain and restore function associated with damaged joints. Infection of joint prostheses occurs rarely but represents very serious complication. Diagnosis of prosthetic joint infections (PJIs) remains difficult. Microbiological culture methods have hitherto been regarded as the reference standard. This case study was designed to assess which molecular tools can most effectively be implemented in a new diagnostic strategy for diagnosing PJIs. We evaluated a 78-year-old man with an acute infection following total hip replacement with microbiological culture methods and molecular methods including: Sanger sequencing of cloned 16S rDNA, 454 Life Sciences-based 16S rRNA pyrosequencing, Ibis T5000 biosensor analysis, and bacterial 16S fluorescence in situ hybridization (FISH). A pre-operative joint aspirate was evaluated by culture methods and 16S rRNA gene PCR which both revealed the same microorganism, Streptococcus dysgalactiae. However, most likely due to the start of antibiotic therapy, perioperative surgical samples obtained two days later were culture-negative, but remained positive by all applied molecular methods. This study suggests that culture-independent molecular methods can be useful for clinical microbiological diagnosis, and it is important for all these methods to achieve short turnaround time, clinical validation and cost-effectiveness to become feasible for diagnostic use.