First experience of a multicenter external quality assessment of molecular 16S rRNA gene detection in bone and joint infections.

The objective of this study was to assess the performance of seven French laboratories for 16S rRNA gene detection by real-time PCR in the diagnosis of bone and joint infection (BJI) to validate a large multicenter study. External quality control (QC) was required owing to the differences in extraction procedures and the molecular equipment used in the different laboratories. Three proficiency sets were organized, including four bacterial DNA extracts and four bead mill-pretreated osteoarticular specimens. Extraction volumes, 16S rRNA gene primers, and sequencing interpretation rules were standardized. In order to assess each laboratory's ability to achieve the best results, scores were assigned, and each QC series was classified as optimal, acceptable, or to be improved. A total of 168 QCs were sent, and 160 responses were analyzed. The expected results were obtained for 93.8%, with the same proportion for extracts (75/80) and clinical specimens (75/80). For the specimens, there was no significant difference between manual and automated extraction. This QC demonstrated the ability to achieve good and homogeneous results using the same 16S rRNA gene PCR with different equipment and validates the possibility of high-quality multicenter studies using molecular diagnosis for BJI.

[IgM Myeloma: case report and literature review]. / Myélome à IgM : à propos d'un cas et revue de littérature.

The presence of serum monoclonal IgM is often associated with the diagnosis of Waldenström macroglobulinemia (WM) or other chronic lymphoproliferative disorders. IgM myeloma is a rare entity (0.5%). We report the case of an IgM myeloma complicated by systemic amyloidosis AL, with an impure nephrotic syndrome and a factor FX deficiency.

A new case of IgE multiple myeloma with review of literature.

IgE myeloma is an extremely rare disease characterized by frequent plasma cell leukemia, little monoclonal-spike on electrophoresis, an high incidence of t(11;14) translocation and a worse survival than those with common myelomas. We report here a new case of IgE myeloma and discuss clinical presentation, biological features and therapeutic option.

Impact of yeast-bacteria coinfection on the detection of Candida sp. in an automated blood culture system.

Invasive candidiasis remains a major cause of morbidity and mortality. It is now well known that an early diagnosis contributes to the patients' outcome. Blood cultures, which are the first-line test in case of bloodstream infection suspicion, can be carried out using fungus-selective medium (containing antibiotics) or standard microorganism medium allowing both bacterial and fungal growth. Some patients can suffer from polymicrobial sepsis involving bacteria and yeasts, so we decided to investigate in blood cultures the influence of the presence of bacteria on fungal development. Simulated blood cultures were performed using Candida albicans or C. glabrata coincubated with Escherichia coli or Staphylococcus aureus at different concentrations. The results showed that, in a standard microorganism medium, bacterial growth could hide the fungal development. Thus, in patients at risk of invasive candidiasis, the use of a specific fungal medium could improve the diagnosis and allow an earlier efficient antifungal treatment.