Publications by authors named "Sandrine Mailler"
Routine identification of Nocardia species by MALDI-TOF mass spectrometry.
Diagn Microbiol Infect Dis
January 2017
We here show adequate species identification for bacterial isolates of the genus Nocardia spp. through VITEK mass spectrometry. Application of a specific sample preparation method in combination with a robust matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) database leads to 94% accurate identification to the species level on a set of 164 isolates.
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- The study focuses on improving the identification of Mycobacterium spp. and Nocardia spp. using MALDI-TOF MS, which is already popular in clinical labs but not yet optimal for these microbes.
- Researchers developed a database including over 2000 mass spectra from 494 strains, correcting ambiguous identifications using molecular analyses, leading to high accuracy in species identification.
- The identification success rate was 90% for Mycobacterium spp. and 88% for Nocardia spp., though some Mycobacterium isolates were difficult to identify due to protein masking; for well-represented species, accuracy was 95% or higher.
Candida auris is an emerging antifungal resistant yeast species causing nosocomial and invasive infections, emphasising the need of improved diagnostics and epidemiological typing methods. We show that MALDI-TOF VITEK-MS followed by amplified length polymorphisms allows for accurate species identification and subsequent epidemiological characterisation of strains encountered during potential outbreaks.
View Article and Find Full Text PDFThe identification of mycobacteria outside biocontainment facilities requires that the organisms first be rendered inactive. Exposure to 70% ethanol (EtOH) either before or after mechanical disruption was evaluated in order to establish a safe, effective, and rapid inactivation protocol that is compatible with identification of Mycobacterium and Nocardia species using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). A combination of 5 min of bead beating in 70% EtOH followed by a 10-min room temperature incubation period was found to be rapidly bactericidal and provided high-quality spectra compared to spectra obtained directly from growth on solid media.
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- Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is now commonly used in clinical labs for identifying bacterial species from isolated colonies but struggles with direct identification from clinical specimens due to sample complexity and mixed microbial populations.
- The article presents a new method using penalized non-negative linear regression to analyze single mass spectra, allowing for the identification of species within polymicrobial samples by leveraging existing reference databases.
- Testing on a large set of mono- and bi-microbial samples showed high accuracy, with only 5.3% of cases misidentified, suggesting this approach could enhance routine clinical microbiology practices.
The development of reliable and rapid methods for the identification of patients colonized with vancomycin-resistant enterococci (VRE) is central to the containment of this agent within a hospital environment. To this end, we evaluated a prototype chromogenic agar medium (VRE-BMX; bioMérieux, Marcy l'Etoile, France) used to recover VRE from clinical specimens. This medium can also identify isolated colonies as either vancomycin-resistant Enterococcus faecium or Enterococcus faecalis, based on distinct colony colors.
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