ABSTRACT
Rapid and reliable identification of microorganisms in the clinical laboratory is essential for an early and accurate diagnosis guiding timely therapy. However, conventional methods are sometimes unreliable and show controversial outcomes. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a rapid and reliable method for identification of bacteria and fungi isolated from clinical samples. Members of the genus Raoultella are increasingly recognized as clinically relevant. There are difficulties in their identification at the species level since sequencing the 16S rRNA or the rpoB genes does not show conclusive results. The aim of this study has been to compare two MALDI-TOF MS systems (Vitek MS and Bruker Biotyper) with Vitek2 and API20E systems for differentiation of Raoultella species. A collection of 97 clinical isolates of Raoultella species was identified with Vitek MS, in parallel with Vitek2 and API, and finally with Bruker Biotyper. Among the two most widely used MALDI-TOF MS platforms, results obtained with Vitek MS were slightly superior to those obtained with the Bruker Biotyper system, with sensitivities and specificities of 98.9/57.9% and 98.8/37.0%, respectively. The current commercial phenotypic identification systems are not optimized for the identification of Raoultella species. Our results indicate that MALDI-TOF-based identification is more accurate and sensitive than that provided by phenotypic methods.
Subject(s)
Bacterial Typing Techniques/methods , Enterobacteriaceae Infections/microbiology , Enterobacteriaceae/classification , Molecular Typing/methods , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Enterobacteriaceae/chemistry , Enterobacteriaceae/isolation & purification , Humans , Molecular Typing/standards , Sensitivity and Specificity , Time FactorsABSTRACT
This study sought to evaluate the effect of classical music, using Mozart's sonata for two pianos (K. 448), on changes in dopamine (DA) levels in the striatal nucleus (SN), prefrontal cortex (PFC) and mesencephalon, and on prolactin (PRL) and corticosterone secretion in adult male Wistar rats. Rats were divided into four groups: (1) control, (2) haloperidol treatment (single dose of 2 mg/kg s.c.), (3) music (two 2-h sessions per day) and (4) haloperidol plus music. Rats were sacrificed 2 h after haloperidol injection. Music prompted a fall in plasma PRL and corticosterone levels in healthy rats (P < 0.05) and prevented the increase in levels triggered by haloperidol (P < 0.001). Moreover, exposure to music was associated with a significant increase in DA levels in all groups, with the increase being particularly marked in PFC and SN (P < 0.001). Haloperidol is a recognised D2 receptor antagonist, and these findings suggest that music, by contrast, enhances DA activity and turnover in the brain. The results obtained here bear out reports that music triggers a reduction in systolic pressure and an increase in mesencephalon dopamine levels in human and rats treated with ecstasy, through a calmodulin-dependent system.