Sonication: a valuable technique for diagnosis and treatment of periprosthetic joint infections.

BACKGROUND: Periprosthetic joint infection (PJI) is the most severe complication, following joint arthroplasty. Identification of the causal microbial factor is of paramount importance for the successful treatment. PURPOSE: The aim of this study is to compare the sonication fluid cultures derived from joint prosthetic components with the respective periprosthetic tissue cultures. METHODS: Explanted prosthesis components for suspected infection were placed into a tank containing sterile Ringer's solution and sonicated for 1 minute at 40 kHz. Sonication fluid cultures were examined for 10 days, and the number and identity of any colony morphology was recorded. In addition, periprosthetic tissue specimens (>5) were collected and cultured according to standard practice. The duration of antimicrobial interruption interval before culture sampling was recorded. RESULTS: Thirty-four patients composed the study group. Sonication fluid cultures were positive in 24 patients (70.5%). Sixteen of thirty four periprosthetic tissue cultures (47.1%) were considered positive, all revealing the same microbial species with the respective sonication fluid cultures: 3 tissue samples showed polymicrobial infection. All tissue cultures were also found positive by the sonication fluid culture. CONCLUSIONS: Sonication fluid cultures represent a cheap, easy, accurate, and sensitive diagnostic modality demonstrating increased sensitivity compared to periprosthetic tissue cultures (70.5 versus 47.1%).

Application of polymerase chain reaction for detection of Legionella pneumophila in serum samples.

OBJECTIVE: To apply the polymerase chain reaction (PCR) to serum samples for the rapid diagnosis of Legionnaire's disease using the L5SL9 and L5SR93 primers designed to generate a 104-base-pair (bp) fragment from the 5S RNA gene of Legionella spp. The amplified product was detected by electrophoresis and by hybridization with the L5S-1-specific probe. METHODS: Single specimens of serum obtained from 24 patients with confirmed legionellosis, at different stages of their disease, were tested by PCR. Additionally, 10 serum samples from patients with no clinical symptoms of pneumonia and 10 samples from patients suffering from pneumonia caused by Mycoplasma pneumoniae, Coxiella burnetii or Chlamydia psittaci were also tested as controls in order to determine the specificity of the method. RESULTS: Of the 24 examined serum samples, the amplified products from 12 hybridized with the L5S-1 probe (sensitivity 50%). None of the negative controls was positive after PCR. No correlation was found between the day of illness and the positivity in the test. CONCLUSIONS: The PCR technique could be applied as a diagnostic tool for the rapid diagnosis of legionellosis in serum samples after modification, mainly to improve its sensitivity.

Direct genetic detection of Dobrava virus in Greek and Albanian patients with hemorrhagic fever with renal syndrome.

Blood samples were collected from an Albanian and a Greek patient with hemorrhagic fever with renal syndrome and tested by reverse transcriptase-polymerase chain reaction. The genetic detection assay amplified hantavirus-specific DNA fragments from RNA extracted from the blood of the patients; nucleotide sequence analysis revealed that the causative agent of the disease was Dobrava virus. These findings suggest that Dobrava virus (which was originally isolated from the lungs of an Apodenws flavicollis mouse in Slovenia) is endemic throughout the Balkan States and causes overt human disease.