Evaluation of ID Fungi Plates Medium for Identification of Molds by MALDI Biotyper.

MALDI-TOF mass spectrometry (MS) identification of pathogenic filamentous fungi is often impaired by difficulties in harvesting hyphae embedded in the medium and long extraction protocols. The ID Fungi Plate (IDFP) is a novel culture method developed to address such difficulties and improve the identification of filamentous fungi by MALDI-TOF MS. We cultured 64 strains and 11 clinical samples on IDFP, Sabouraud agar-chloramphenicol (SAB), and ChromID Candida agar (CAN2). We then compared the three media for growth, ease of harvest, amount of material picked, and MALDI-TOF identification scores after either rapid direct transfer (DT) or a long ethanol-acetonitrile (EA) extraction protocol. Antifungal susceptibility testing and microscopic morphology after subculture on SAB and IDFP were also compared for ten molds. Growth rates and morphological aspects were similar for the three media. With IDFP, harvesting of fungal material for the extraction procedure was rapid and easy in 92.4% of cases, whereas it was tedious on SAB or CAN2 in 65.2% and 80.3% of cases, respectively. The proportion of scores above 1.7 (defined as acceptable identification) were comparable for both extraction protocols using IDFP (P = 0.256). Moreover, rates of acceptable identification after DT performed on IDFP (93.9%) were significantly higher than those obtained after EA extraction with SAB (69.7%) or CAN2 (71.2%) (P = <0.001 and P = 0.001, respectively). Morphological aspects and antifungal susceptibility testing were similar between IDFP and SAB. IDFP is a culture plate that facilitates and improves the identification of filamentous fungi, allowing accurate routine identification of molds with MALDI-TOF-MS using a rapid-extraction protocol.

Simultaneous Quantification of Adalimumab and Infliximab in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry.

BACKGROUND: Adalimumab (ADA) and infliximab (IFX) are therapeutic monoclonal antibodies targeting tumor necrosis factor-alpha (TNFα). They are used to treat inflammatory diseases. Clinical trials have suggested that therapeutic drug monitoring for ADA or IFX could improve treatment response and cost effectiveness. However, ADA and IFX were quantified by ELISA in all these studies, and the discrepancies between the results obtained raise questions about their reliability. We describe here the validation of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of ADA and IFX in human samples. METHODS: Full-length antibodies labeled with stable isotopes were added to plasma samples as an internal standard. Samples were then prepared using Mass Spectrometry Immunoassay followed by trypsin digestion before ADA and IFX quantification by LC-MS/MS. ADA and IFX were quantified in serum from patients treated with ADA (n = 21) or IFX (n = 22), and the concentrations obtained were compared with those obtained with a commercial ELISA kit. RESULTS: The chromatography run lasted 8.6 minutes, and the quantification range was 1-26 mg/L. The method was reproducible, repeatable, and accurate. For both levels of internal quality control, for ADA and IFX, interday and intraday coefficients of variation and accuracies were all within 15%, in accordance with FDA recommendations. No significant cross-contamination effect was noted. Good agreement was found between LC-MS/MS and ELISA results, for both ADA and IFX. CONCLUSIONS: This LC-MS/MS method can be used for the quantification of ADA and IFX in a single analytical run and for the optimization of LC-MS/MS resource use in clinical pharmacology laboratories.