The rapid detection and/or identification (ID) of the microbial pathogens responsible for bloodstream infections (BSIs) is pivotal for reducing infection-related mortality and costs (1), particularly for severely ill patients (2, 3). Although blood culture (BC) continues to be essential for BSI diagnosis, the turnaround time for ID can be accelerated using new technologies that are directly applied to positive BC bottles/broths (4).Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was recently demonstrated to improve the clinical management of BSIs (5, 6) and allow patients to receive appropriate antimicrobial therapy earlier (i.e., 24 h from the first positive BC) (7). However, despite its well-documented good performance (8-17), this method often fails to identify polymicrobial BCs in their entirety.Another method is the multiplex PCR-based FilmArray blood culture ID (BCID) panel (bioMérieux, Marcy l'Etoile, France), which is equally as fast as the MALDI-TOF MS (e.g., MALDI BioTyper system [Bruker Daltonics, Bremen, Germany]). This technique was developed for the simultaneous identification of 24 microbial pathogens, including 19 bacterial genera/species and 5 Candida species (and 3 antibiotic resistance determinants). In addition to its high sensitivity and specificity, the FilmArray BCID panel has proven to be accurate for identifying not only monomicrobial but also polymicrobial . Notably, successful results were obtained with BC broths tested before the bottles became positive or even before the bottles were incubated in the BC instrument as usual (24). To date, the extensive use of the FilmArray BCID panel in routine clinical laboratory practice has been hampered by the high cost of reagents/consumables.In this study, we developed a BSI diagnostic algorithm that relied on the direct analysis of positive BC bottles/broths using the MALDI BioTyper system supplemented with the FilmArray BCID panel. We evaluated this algorithm in terms of ID accuracy and turnaround time by comparing the results with a reference culture-based procedure.(This work has been presented in part as a poster at the 24th European Congress of Clinical Microbiology and Infectious Diseases, 10 to 13 May 2014, Barcelona, Spain).

BackgroundNowadays, the global spread of resistance to oxyimino-cephalosporins in Enterobacteriaceae implies the need for novel diagnostics that can rapidly target resistant organisms from these bacterial species.MethodsIn this study, we developed and evaluated a Direct Mass Spectrometry assay for Beta-Lactamase (D-MSBL) that allows direct identification of (oxyimino)cephalosporin-resistant Escherichia coli or Klebsiella pneumoniae from positive blood cultures (BCs), by using the matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) technology.ResultsThe D-MSBL assay was performed on 93 E. coli or K. pneumoniae growing BC samples that were shortly co-incubated with cefotaxime (CTX) as the indicator cephalosporin. Susceptibility and resistance defining peaks from the samples’ mass spectra were analyzed by a novel algorithm for bacterial organism classification. The D-MSBL assay allowed discrimination between E. coli and K. pneumoniae that were resistant or susceptible to CTX with a sensitivity of 86.8% and a specificity of 98.2%.ConclusionThe proposed algorithm-based D-MSBL assay, if integrated in the routine laboratory diagnostic workflow, may be useful to enhance the establishment of appropriate antibiotic therapy and to control the threat of oxyimino-cephalosporin resistance in hospital.

SummaryBackground. Clostridium difficile infections are the main cause of nosocomial acquired diarrhea, because of prolonged antibiotic regimens. In the last years, mortality has increased due to recurrent infections caused by metronidazole and vancomicin resistant hypervirulent C. difficile strain 027. Faecal Microbiota Transplantation (FMT) is an infusion of faecal material obtained from healthy donors. This procedure reduces mortality in recurrent C. difficile infections (CDI). In this study we identified bacterial species obtained from donors' stool samples using culturomics.Materials and methods. Three donors were selected for FMT in three recipients affected by CDI. Faces obtained for FMT underwent culturomics, applying 17 different culture methods.Results and conclusions. Several different bacteria were isolated from donors. In two donors 4 potentially pathogenic bacteria were isolated; this suggests the use of culturomics for donors' screening or for selection of bacteria to infuse.