Objectives Severe acute respiratory syndrome coronavirus (SARS-CoV-2) is a novel coronavirus that causes COVID-19. This disease is associated with leukocytosis with lymphopenia, neutrophilia, and elevated levels of d-dimer, and C-reactive protein, ferritin, procalcitonin, and lactate dehydrogenase. The aim of this study was to describe the clinical and analytical characteristics of hospitalized patients with SARS-CoV-2 infection and to identify prognostic factors of disease progression. Methods Patients were categorized into two groups based on COVID-19 severity. Study variables included demographic data, medical history, length of hospital stay, course of pneumonia, drug therapy, and analytical parameters. A descriptive and multivariate analysis was performed to identify prognostic factors for disease severity. Results The study population included 197 patients, of whom 127 had mild disease and 70 had severe COVID-19. Statistically significant differences were observed in most analytical parameters. The parameters included in the multivariate analysis were advanced age and elevated levels of leukocytes, CRP, GGT, and PCT at admission as prognostic factors for disease severity. Conclusions The prognostic factors for the severity of SARS-CoV-2 infection identified in this study (age, leukocytes, CRP, GGT, and PCT) will help predict the course of the disease at an early stage.

Metabolites produced by an altered gut microbiota might mediate the effects in the brain. Among metabolites, the fecal volatile organic compounds (VOCs) are considered to be potential biomarkers. In this study, we examined both the VOCs and bacterial taxa in the feces from healthy subjects and Alzheimer’s disease (AD) patients at early and middle stages. Remarkably, 29 fecal VOCs and 13 bacterial genera were differentiated from the healthy subjects and the AD patients. In general, higher amounts of acids and esters were found in in the feces of the AD patients and terpenes, sulfur compounds and aldehydes in the healthy subjects. At the early stage of AD, the most relevant VOCs with a higher abundance were short-chain fatty acids and their producing bacteria, Faecalibacterium and Lachnoclostridium. Coinciding with the development of dementia in the AD patients, parallel rises of heptanoic acid and Peptococcus were observed. At a more advanced stage of AD, the microbiota and volatiles shifted towards a profile in the feces with increases in hexanoic acid, Ruminococcus and Blautia. The most remarkable VOCs that were associated with the healthy subjects were 4-ethyl-phenol and dodecanol, together with their possible producers Clostridium and Coprococcus. Our results revealed a VOCs and microbiota crosstalk in AD development and their profiles in the feces were specific depending on the stage of AD. Additionally, some of the most significant fecal VOCs identified in our study could be used as potential biomarkers for the initiation and progression of AD.

Trichomoniasis, a disease caused by Trichomonas vaginalis, is the most common non-viral sexually transmitted infection worldwide. The importance of its diagnosis lies in its ease of transmission and the absence of symptoms in most cases, as occurs in men, which have a significant role as asymptomatic carriers. The most widely used diagnostic methods are the fresh examination of vaginal or urethral secretions and molecular techniques. However, as they have some disadvantages and, sometimes, low sensitivity, new trichomoniasis diagnostic methods are necessary. Volatile organic compounds in clinical samples are effective in the diagnosis of different diseases. This work aimed to study, for the first time, those present in vaginal discharge and urine of patients with Trichomonas vaginalis infection to look for volatile biomarkers. The results showed that volatile compounds such as 2-methyl-1-propanol and cyclohexanone could serve as biomarkers in vaginal discharge samples, as well as 2-octen-1-ol and 3-nonanone in urine. Moreover, 3-hydroxy-2,4,4-trimethylpentyl 2-methylpropanoate found in vaginal discharge, highly correlated to positive patients, is also highly related to urines of patients with trichomoniasis. The biomarkers described in this study might be a promising diagnostic tool. Key Points • The incidence of Trichomonas vaginalis infection is increasing • Trichomonas vaginalis VOC study in vaginal discharge and urine was performed • The identification of volatile biomarkers could allow a new diagnostic method

Microorganisms produce a wide variety of volatile organic compounds (VOCs) as products of their metabolism and some of them can be specific VOCs linked to the microorganism's identity, which have proved to be helpful for the diagnosis of infection via odour fingerprinting. The aim of this study was to determine the VOCs produced and consumed to characterize the volatile metabolism of seven isolates of different clonal complexes (CCs) of Listeria monocytogenes . For this purpose, dichloromethane extracts from the thioglycolate broth medium were analysed by gas chromatography coupled to mass spectrometry (GC/MS). Also, multivariate analyses were applied to the data obtained. Results showed that all the isolates of L. monocytogenes produced de novo isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-(methylthio)−1-propanol, acetic acid, isobutyric acid, butanoic acid, and isovaleric acid. Significant differences were found among isolates for the production amount of these volatiles, which allowed their differentiation. Thus, CC4 (ST-219/CT-3650) and CC87 (ST-87/CT-4557) showed an active volatile compounds metabolism with high consumption nitrogen and sulphur compounds and production of alcohols and acids, and CC8 (ST-8/CT-8813) and CC3 (ST-3/CT-8722) presented a less active volatile metabolism. Moreover, within the VOCs determined, huge differences were found in the production of butanol among the seven isolates analysed, being probably a good biomarker to discriminate among isolates belonging to different CCs. Hence, the analysis of volatile profile generated by the growth of L. monocytogenes in vitro could be a useful tool to differentiate among CCs isolates.

Conflicto de interés: los autores declaran que no existen conflictos de interés. RESUMENIntroducción: la infección por SARS-CoV-2 ha generado un impacto sin precedentes en la salud pública a nivel mundial. El objetivo de este estudio fue la identificación de factores pronósticos de muerte en pacientes con COVID-19 ingresados en unidades de cuidados intensivos (UCI) para predecir el curso de la infección en las etapas críticas.Métodos: estudio descriptivo en el que se incluyen pacientes con infección por SARS-CoV-2 ingresados en la UCI de un hospital de área (Sevilla, España) entre el 25 de agosto de 2020 y el 21 de mayo de 2021.Los pacientes fueron clasificados en recuperados y fallecidos, en función del desenlace de su estancia en UCI. Se realizó un análisis multivariante para conocer los factores pronósticos de muerte.Resultados: la población de este estudio incluyó a 164 pacientes, con una mediana de edad de 71 años, siendo la tasa de mortalidad del 65,9 %. Se encontraron diferencias estadísticamente significativas entre los dos grupos en la edad y algunos parámetros de laboratorio (leucocitos, neutrófilos, hematíes, urea y potasio) en el momento del ingreso en UCI.Los parámetros con mayor asociación a la muerte de los pacientes fueron una edad superior a 63 años, neutrófilos > 10,2 × 10 9 /L, urea > 7,2 mmol/L y hematíes ≤ 4,7 × 10 12 /L.Conclusiones: los factores pronósticos de muerte en pacientes con COVID-19 ingresados en UCI identificados en este estudio (edad, neutrófilos, urea y hematíes) pueden ser empleados para predecir el curso de la infección en las etapas críticas, permitiendo a los clínicos adelantarse al posible desenlace de la enfermedad.