title: Identification of silent prosthetic joint infection: preliminary report of a prospective controlled study.
abstract: OBJECTIVE
  We will test the hypothesis that ultrasound supported by polymerase chain reaction (PCR) could improve bacterial identification in non-infected prosthetic joint loosening. The aim was to detect bacterial species in non-infected prosthetic joint loosening using ultrasound and 16S rRNA gene sequencing.
  
  
  METHODS
  A total of 16 patients (11 women and five men) aged 46-80 years (mean age 65.7) with diagnosed knee or hip implant loosening (mean implant survival of 102.1 months) were investigated. Bacterial culture and DNA sequencing were used to detect bacteria on the surface of failed implants removed during revision arthroplasty. The results of pre- and intraoperative culture and DNA sequencing were compared. Histopathological analysis was also performed.
  
  
  RESULTS
  The number of positive cultures rises with a higher level of C-reactive protein (CRP). The results of the cultures from synovial fluid obtained through joint aspiration were consistent with sonicates from components of prostheses in 12 cases (75%). Bacterial DNA was found in 90% of patients with negative synovial fluid culture. PCR revealed two or more bacterial species, often of the same genus: Ralstonia pickettii, Pseudomonas spp., Brevibacterium spp., Lactobacillus spp., Propionibacterium spp. and Staphylococcus spp.These are micro-organisms present in the environment or on the human body and often associated with compromised immunity.
  
  
  CONCLUSIONS
  The ultrasound procedure followed by PCR and sequencing improve bacterial identification in silent prosthetic joint infection. The lack of clinical signs of infection and negative preoperative and intraoperative cultures do not exclude the presence of micro-organisms on the implants.
authors.affiliation: Department of Orthopaedics and Traumatology, Medical University of Silesia, Ziołowa 45/47, 40-635, Katowice, Poland, pberez@o2.pl.
authors.forename: Przemysław L
authors.initials: PL
authors.lastname: Bereza
authors.forename: Alicja
authors.initials: A
authors.lastname: Ekiel
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Auguściak-Duma
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Aptekorz
authors.forename: Iwona
authors.initials: I
authors.lastname: Wilk
authors.forename: Damian J
authors.initials: DJ
authors.lastname: Kusz
authors.forename: Piotr
authors.initials: P
authors.lastname: Wojciechowski
authors.forename: Gayane
authors.initials: G
authors.lastname: Martirosian
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D019544:Equipment Failure Analysis; D005260:Female; D006622:Hip Prosthesis / Q000382:microbiology*; D006801:Humans; D007432:Intraoperative Period; D007720:Knee Prosthesis / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D057234:Preoperative Period; D011446:Prospective Studies; D011475:Prosthesis Failure / Q000209:etiology*; D016459:Prosthesis-Related Infections / Q000175:diagnosis* / Q000382:microbiology*; D012343:RNA, Transfer / Q000235:genetics; D017421:Sequence Analysis; D014465:Ultrasonics / Q000379:methods*
chemical_list: D012343:RNA, Transfer