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Rybak M.J.,Anti Infective Research Laboratory | Rybak M.J.,Wayne State University | Vidaillac C.,Anti Infective Research Laboratory | Vidaillac C.,CRP Sante | And 8 more authors.
Journal of Clinical Microbiology | Year: 2013

We evaluated the ability of four commercial MIC testing systems (MicroScan, Vitek 2, Phoenix, and Etest) to detect vancomycin MIC values of ≤ 1 to ≥ 2 in 200 methicillin-resistant Staphylococcus aureus (MRSA) strains compared to the Clinical and Laboratory Standards Institute broth microdilution (BMD) reference methods. Compared to the BMD method, absolute agreement (0±dilution) was highest for the Phoenix system (66.2%) and the MicroScan turbidity method (61.8%), followed by the Vitek 2 system (54.3%). The Etest produced MIC values 1 to 2 dilutions higher than those produced by the BMD method (36.7% agreement). Of interest, the MicroScan system (prompt method) was more likely to overcall an MIC value of 1 mg/liter (74.1%), whereas the Phoenix (76%) and Vitek 2 (20%) systems had a tendency to undercall an MIC of 2 mg/liter. The ability to correctly identify vancomycin MIC values of 1 and 2 has clinical implications and requires further evaluation. © 2013, American Society for Microbiology. Source

Li H.,Wayne State University | Spencer L.,Wayne State University | Nahhas F.,Wayne State University | Nahhas F.,Detroit Medical Center University Laboratories | And 8 more authors.
Molecular Genetics and Metabolism | Year: 2014

Biotinidase deficiency (BD) is an autosomal recessive disorder resulting in the inability to recycle the vitamin biotin. Individuals with biotinidase deficiency can develop neurological and cutaneous symptoms if they are not treated with biotin. To date, more than 165 mutations in the biotinidase gene (BTD) have been reported. Essentially all the mutations result in enzymatic activities with less than 10% of mean normal serum enzyme activity (profound biotinidase deficiency) with the exception of the c.1330G > C (p.D444H) mutation, which results in an enzyme having 50% of mean normal serum activity and causes partial biotinidase deficiency (10-30% of mean normal serum biotinidase activity) if there is a mutation for profound biotinidase deficiency on the second allele. We now reported eight novel mutations in ten children identified by newborn screening in Michigan from 1988 to the end of 2012. Interestingly, one intronic mutation, c.310-15delT, results in an approximately two-fold down-regulation of BTD mRNA expression by Quantitative real-time reverse-transcription PCR (qRT-PCR). This is the first report of an intronic mutation in the BTD gene with demonstration of its effect on enzymatic activity by altering mRNA expression. This study identified three other mutations likely to cause partial biotinidase deficiency. These results emphasize the importance of full gene sequencing of BTD on patients with biotinidase deficiency to better understand the genotype and phenotype correlation in the future. © 2014 Elsevier Inc. Source

Mehta T.,Beaumont Hospital | McGrath E.,Wayne State University | Bheemreddy S.,Wayne State University | Salimnia H.,Wayne State University | And 9 more authors.
Journal of Clinical Microbiology | Year: 2010

Two immunocompromised patients with 2009 H1N1 influenza pneumonia had viral shedding for over 5 weeks despite therapy with oseltamivir. Declining or persistently low cycle threshold values noted on serial qualitative real-time reverse transcriptase PCR (rRT-PCR) of respiratory specimens implied increasing viral load and probable drug resistance. Oseltamivir resistance was later confirmed by pyrosequencing. Copyright © 2010, American Society for Microbiology. All Rights Reserved. Source

Inutan E.D.,Wayne State University | Wager-Miller J.,Indiana University Bloomington | Narayan S.B.,Detroit Medical Center University Laboratories | Mackie K.,Indiana University Bloomington | Trimpin S.,Wayne State University
International Journal for Ion Mobility Spectrometry | Year: 2013

Recently discovered ionization methods for use in mass spectrometry (MS), are widely applicable to biological materials, robust, and easy to automate. Among these, matrix assisted ionization vacuum (MAIV) is astonishing in that ionization of low and high-mass compounds are converted to gas-phase ions with charge states similar to electrospray ionization simply by exposing a matrix:analyte mixture to the vacuum of a mass spectrometer. Using the matrix compound, 3-nitrobenzonitrile, abundant ions are produced at room temperature without the need of high voltage or a laser. Here we discuss chemical analyses advances using MAIV combined with ion mobility spectrometry (IMS) real time separation, high resolution MS, and mass selected and non-mass selected MS/MS providing rapid analyte characterization. Drugs, their metabolites, lipids, peptides, and proteins can be ionized simultaneously from a variety of different biological matrixes such as urine, plasma, whole blood, and tissue. These complex mixtures are best characterized using a separation step, which is obtained nearly instantaneously with IMS, and together with direct ionization and MS or MS/MS provides a fast analysis method that has considerable potential for non-targeted clinical analyses. © 2013 Springer-Verlag Berlin Heidelberg. Source

Fairfax M.R.,Wayne State University | Fairfax M.R.,Detroit Medical Center University Laboratories | Lephart P.R.,Detroit Medical Center University Laboratories | Salimnia H.,Wayne State University | Salimnia H.,Detroit Medical Center University Laboratories
Frontiers in Microbiology | Year: 2014

Weissella confusa is found in fermented foods and has been suggested as a probiotic, but also causes sepsis and other serious infections in humans and animals. The incidence of human infections is underestimated partly due to confusion with viridans streptococci and partly due to difficulty making a definitive identification, even if the organism is recognized to belong to another genus, owing to the inability of commercial organism systems to identify it. We report our experiences identifying W. confusa isolated from two immune-compromised patients, both of whom developed sepsis with this organism. Two MicroScan gram positive combination panels, could not identify the organism because they did not have W. confusa in their data bases, but did not provide a false identification. Other laboratorians have reported failure to identify or false identifications of W. confusa with other commercial systems. W. confusa is in the data base of the RapID™ Str panel (Remel), which gave three incorrect, high probability results (=95%). 16S rDNA sequencing identified the isolates as W. confusa. Maldi-Tof, performed by two of our reference laboratories, also correctly identified both isolates. Use of W. confusa as a probiotic should be approached with caution because its true incidence as an opportunisitic pathogen is unknown. © 2014 Fairfax, Lephart and Salimnia. Source

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