[Analysis of the demand for detection of SARSCoV-2 in a health area of Spain]. / Análisis de la demanda de detección de SARS-CoV-2 en un área de salud de España.

OBJECTIVE: Since the discovery of the SARS-CoV-2 virus, the polymerase chain reaction technique (RT-PCR) has become the fundamental method for diagnosing the disease in its acute phase. The objective is to describe the demand-based series of RT-PCR determinations received at a Microbiology Service at a third-level reference hospital for a health area for three months spanning from the onset of the epidemic by SARS-CoV-2. METHODS: A retrospective analysis of the total of the RT-PCR requested in the Microbiology Service analyzed from 02/25/2020 to 05/26/2020 (90 days) has been carried out. They have been grouped by epidemiological weeks and by the petitioner service. A descriptive analysis was carried out by age, gender and number of requests for each patient. In the tests carried out, a confidence level of 95% (p <0.05) was considered significant. RESULTS: A total of 27,106 requests was received corresponding to 22,037 patients. Median age 53.7 (RIC 40.9-71.7) years, women: 61.3%. Proportion of patients with any positive RT-PCR: 14%. Of the total requests for RT-PCR, positive 3,710. Week 13 had the highest diagnosis performance (39.0%). The primary care has been the service thar has made the most requests (15,953). Patients with 3 or more RT-PCR: 565, of them, 19 patients had a positive result after previously having a negative one. CONCLUSIONS: Requests have been increasing depending on the evolution of the epidemic. The RT-PCR has a high diagnostic performance in the phases of highest contagiousness and / or transmissibility of the virus.

Shewanella putrefaciens in a fuel-in-water emulsion from the Prestige oil spill.

Microorganisms that colonize the fuel-in-water emulsion from the Prestige spill have been compared with those from Exxon-Valdez. Both emulsions contained non-fermentative gram-negative rods but unlike Exxon-Valdez's, the Prestige's spill contained anaerobic bacteria and no fungi. Our main finding has been the identification of Shewanella putrefaciens , a bacterium promising for bioremediation.

Differential scanning calorimetry investigations on LPS and free lipids A of the bacterial cell wall.

Differential scanning calorimetry (DSC) was used to investigate the thermal stability and behaviour of the lipopolysaccharides (LPS) of the outer membrane of Gram-negative bacteria and their lipid portion. DSC curves of LPS show thermal features between 200 and 129 degrees C (depolymerization) and between -13 and -36 degrees C (cooling phase transition). Both effects were related to the relative strength of the linkage types in the O-chain structure and to their capacity for intermolecular hydrogen bonding. DSC curves of lipids A show endotherm peaks between 40 and 24 degrees C, around 15 degrees C and between -23 and -4 degrees C. Based on these effects, strong differences in thermal behaviour can be observed between that of Brucella and Vibrio cholerae on the one hand, and that of Escherichia coli and Shigella flexneri on the other. Fluidity of the acyl chains and lyotropism, which are important parameters in expression of biological activities, are discussed using the above data. To explain some properties, fluidity could be related to the temperature of the gel<==>liquid crystalline (beta<==>alpha) phase transition, which occurs at physiological temperature. Nevertheless, fluidity could be related to temperature of the previous thermal effect (between 6 and 20 degrees C), for which a softening or partial melting of the sample has been evidenced. The thermal effect measured between -23 degrees C and -4 degrees C indicates a greatly reduced water concentration of lipid A from Brucella, thus explaining its early fusion process and its activity by means of hydrophobic interactions.

Thermolytical techniques to characterize fungal polysaccharides and bacterial lipopolysaccharides.

The present work constitutes an entirely novel contribution in the scope of microbiology and especially in taxonomy, introducing thermolysis curves as a rapid method of characterization of fungal polysaccharides and bacterial lipopolysaccharides. The thermal analysis techniques applied were thermogravimetry and derivative thermogravimetry (TG-DTG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). Each thermogram of a sample is represented by one or a few temperatures and, in DSC, by complementary enthalpy data. The temperatures of the thermograms from structurally unknown polysaccharides are compared with those used as references, and thus, information on their composition, linkage types, and anomeric configuration can be deduced. The situation is more complicated for bacterial lipopolysaccharides, but in whatever mode, a structural estimation is always possible. In the course of the development and validation of the thermal method, structural findings on relative stabilities of linkage types (valuable in carbohydrate research) have been recognized and are therefore also described in this work.