Ausina, V. (Vicente)

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    Evaluation of the SediMax automated microscopy sediment analyzer and the Sysmex UF-1000i flow cytometer as screening tools to rule out negative urinary tract infections
    (Elsevier, 2016) Ausina, V. (Vicente); Fernández-Rivas, G. (Gema); Casamajor, T. (Teresa); Coello, A. (Andreu); Marcó, C. (Clara); Iñigo, M. (Melania); Fernández, A. (Anabel); Carrasco, M. (María)
    Urinary tract infections (UTI) are highly prevalent in nosocomial and community settings, and their diagnosis is costly and time-consuming. Screening methods represent an important advance towards the final UTI diagnosis, diminishing inappropriate treatment or clinical complications. Automated analyzers have been developed and commercialized to screen and rule out negative urine samples. The aim of this study was to evaluate two of these automated analyzers (SediMax, an automatic sediment analyzer and UF-1000i a flow cytometer) to predict negative urine cultures. A total of 1934 urine samples were analyzed. A very strong correlation for white blood cells (WBC) (rs: 0.928) and a strong correlation for bacteria (BAC) (rs: 0.693) were obtained. We also calculated optimal cut-off points for both autoanalyzers: 18 WBC/μL and 97 BAC/μL for SediMax (sensitivity = 96.25%, specificity = 63.04%, negative predictive value = 97.97%), and 40 WBC/μL and 460 BAC/μL for UF-1000i (sensitivity = 98.13%, specificity = 79.16%, negative predictive value = 99.18%). The use of SediMax and UF- 1000i resulted in a 46.33% and 57.19% reduction of all samples cultured, respectively. In conclusion, both ana- lyzers are good UTI screening tools in our setting.
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    Direct Identification of Urinary Tract Pathogens from Urine Samples, Combining Urine Screening Methods and Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry
    (American Society for Microbiology, 2016) Hidalgo, J. (Jessica); Ausina, V. (Vicente); Rivaya, B. (Belén); Fernández-Rivas, G. (Gema); Quesada, M.D. (María Dolores); Coello, A. (Andreu); Iñigo, M. (Melania)
    Early diagnosis of urinary tract infections (UTIs) is essential to avoid inadequate or unnecessary empirical antibiotic therapy. Microbiological confirmation takes 24 to 48 h. The use of screening methods, such as cytometry and automated microscopic analysis of urine sediment, allows the rapid prediction of negative samples. In addition, matrix-assisted laser desorption ioniza- tion–time of flight mass spectrometry (MALDI-TOF MS) is a widely established technique in clinical microbiology laboratories used to identify microorganisms. We evaluated the ability of MALDI-TOF MS to identify microorganisms from direct urine samples and the predictive value of automated analyzers for the identification of microorganisms in urine by MALDI-TOF MS. A total of 451 urine samples from patients with suspected UTIs were first analyzed using the Sysmex UF-1000i flow cytometer, an automatic sediment analyzer with microscopy (SediMax), culture, and then processed by MALDI-TOF MS with a simple triple- centrifuged procedure to obtain a pellet that was washed and centrifuged and finally applied directly to the MALDI-TOF MS plate. The organisms in 336 samples were correctly identified, mainly those with Gram-negative bacteria (86.10%). No microor- ganisms were misidentified, and no Candida spp. were correctly identified. Regarding the data from autoanalyzers, the best bac- teriuria cutoffs were 1,000 and 200 U/l for UF-1000i and SediMax, respectively. It was concluded that the combination of a urine screening method and MALDI-TOF MS provided a reliable identification from urine samples, especially in those contain- ing Gram-negative bacteria.