Volatile biomarkers of Gram-positive bacteria of clinical relevance as a tool for infection diagnosis.

AIM: Volatile organic compounds (VOCs) are being studied as potential biomarkers in many infections. Therefore, this study aimed to analyze the volatile profile of three Gram-positive bacteria of clinical relevance to identify potential volatile biomarkers that allow their differentiation. METHODS AND RESULTS: L. monocytogenes, S. aureus, and E. faecalis clinical isolates were inoculated in a thioglycollate medium until grown. Then, VOCs were extracted by solid-phase microextraction, and the data obtained were subjected to multivariate analysis. According to our results, there was a high production of aldehydes in E. faecalis. In the case of alcohols, they only increased in L. monocytogenes, while ketones were produced significantly in all three bacteria, mainly due to acetoin. Acids were produced significantly in E. faecalis and L. monocytogenes. CONCLUSIONS: Potential biomarkers of L. monocytogenes could be 1-butanol and 2-methylbutanoic acid. In the case of E. faecalis, the VOC most related to its presence was nonanal. Lastly, potential biomarkers of S. aureus could be isoamyl butanoate and methionol, although some pyrazines have also been associated with this bacterium. SIGNIFICANCE AND IMPACT OF THE STUDY: The identification of potential biomarkers of these clinically relevant bacteria could open the way for the diagnosis of these infections through the analysis of volatile compounds.

Volatile compounds from in vitro metabolism of seven Listeria monocytogenes isolates belonging to different clonal complexes.

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.

Frecuencia de parasitismo intestinal en niños con diarrea persistente en el Área Sanitaria Sur de Sevilla

RESUMEN Introducción: La diarrea persistente está incluida en una gran categoría denominada síndrome de diarrea crónica, problema relativamente común de consulta médica en la edad pediátrica. La importancia y prevalencia de la diarrea persistente de etiología parasitaria es poco conocida en España. Objetivo: Determinar la prevalencia de parasitismo intestinal en niños con síndrome de diarrea persistente, así como las características clínicas asociadas a la etiología parasitaria en el Área Sanitaria Sur de Sevilla (España). Métodos: Estudio retrospectivo y de corte transversal realizado en un año (mayo de 2017-mayo de 2018). Se incluyeron a pacientes en edad pediátrica que consultaban por cuadro diarreico superior a 2 semanas y/o dolor abdominal. El estudio de laboratorio incluyó la determinación de sustancias reductoras, leucocitos fecales y grasas, además del estudio de la etiología infecciosa (bacterias, virus o parásitos). Resultados: De los 777 niños incluidos, 406 (52,3 %) correspondían al sexo masculino y 37 (147,7 %) al sexo femenino, con edades entre 1 mes y 14 años (mediana= 6 años). La presencia de parásitos fue detectada en el 6,9 % (54/777) de las muestras. Cuando se estratificaron los resultados por tipo de parasito, se observó que el 24,1% (13 casos) correspondía a Giardia sp., 14,8 % (8 casos) a Cryptosporidium sp., 55,6 % (30 casos) a Blastocystis sp., 3,6 % (2 casos) a Dientamoeba sp. y 1,9 % (1 caso) a Endolimax sp. Conclusiones: Los resultados revelan un escenario en el que la prevalencia de parásitos con valor clínico demostrado fue del 2,7 %. Esto lleva a considerar la conveniencia de incluir el estudio de parásitos en una segunda fase, después de descartar otras condiciones clínicas más prevalentes en niños con diarrea persistente, además de limitar el estudio de parásitos a la detección de Giardia sp. y Cryptosporidium sp.

ABSTRACT Introduction: Persistent diarrhea belongs in a large category known as chronic diarrhea syndrome, a relatively common concern in children's medical consultation. The importance and prevalence of persistent diarrhea of parasitic etiology are not sufficiently known in Spain. Objective: Determine the prevalence of intestinal parasite infection in children with persistent diarrhea syndrome and the clinical characteristics associated to its parasitic etiology in Seville South Health Area (Spain). Methods: A cross-sectional retrospective study was conducted during one year (May 2017 to May 2018) of patients in pediatric ages who attended consultation for a diarrhea picture of more than two weeks' evolution and/or abdominal pain. Laboratory testing included determination of reducing substances, fecal leukocytes and fats, as well as of the causative agents of the infection (bacteria, viruses or parasites). Results: Of the 777 children included in the study, 406 (52.3%) were male and 37 (147.7%) were female; mean age was six years (1 month to 14 years). Parasites were detected in 6.9% (54/777) of the samples. Stratification of results by parasite type showed that 24.1% (13 cases) corresponded to Giardia sp., 14.8 % (8 cases) to Cryptosporidium sp., 55.6 % (30 cases) to Blastocystis sp., 3.6 % (2 cases) to Dientamoeba sp. y 1.9 % (1 case) to Endolimax sp. Conclusions: According to the results obtained, the prevalence of parasites with demonstrated clinical value is 2.7%. It is therefore advisable to include the study of parasites in a second stage, after ruling out other clinical conditions which are more prevalent in children with persistent diarrhea, and limit the study to the detection of Giardia sp. and Cryptosporidium sp.

Lipofuscinosis neuronal ceroidea y síndrome de Bardet-Biedl en paciente con retinosis pigmentaria / Neuronal ceroid lipofuscinosis and Bardet-Biedl syndrome in patient with retinitis pigmentosa

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Prognostic factors for the severity of SARS-CoV-2 infection.

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.

Evaluation of Routine Blood Tests for Diagnosis of Suspected Coronavirus Disease 2019.

BACKGROUND: Real-time reverse transcription polymerase chain reaction assay (RT-PCR) is the gold standard for diagnosis of coronavirus disease 2019 (COVID-19); however, it is not universally available and may have limitations in response times. The aim was to evaluate the routine blood tests for diagnosis of COVID-19, determining the diagnostic accuracy of blood biomarkers to differentiate between patients with and without COVID-19. METHODS: Clinical charts, nursing records, laboratory findings, and chest x-rays from adult patients with clinical suspicion of COVID-19 (fever, cough and/or dyspnea) at hospital admission were reviewed. Patients were classified into two groups according to RT-PCR COVID-19: positive (COVID-19) or negative (NON-COVID-19). Diagnostic accuracy was determined by analyzing receiver operating characteristic (ROC) curve, calculating the area under the ROC curve (AUC) and the cutoff value. In order to reduce the number of false positives, the cutoff value with a specificity of 80% was considered. RESULTS: Two hundred three patients (101 females, 102 males) with ages between 18 and 96 years (mean = 61.3) were studied. Ninety-four were COVID-19 and 109 were NON-COVID-19. Plasma ferritin level was the most accurate biomarker (AUC = 0.847 and 0.804 in women and men, respectively). The following diagnostic criteria for suspected COVID-19 were established with biomarker cutoff values to differentiate between COVID-19 and NON-COVID-19 patients: lymphocytes ≤ 1.0 x 109/L; eosinophils ≤ 0.02 x 109/L; ferritin > 125% of upper reference limit (URL); LDH > 125% of URL; hsCRP > 80 mg/L; and D-dimer > 1.2 mg/L. Sensitivity was 66%, 64% 62%, 46%, 43%, and 33% for ferritin, eosinophils, LDH, hsCRP, lymphocytes, and D-dimer, respectively. Of those determined to be COVID-19 patients, 91% met one or more of the diagnostic criteria with these blood biomarkers, and of the NON-COVID-19 patients, 47% did not met any diagnostic criteria. CONCLUSIONS: Blood counts of lymphocytes and eosinophils, and plasma levels of D-dimer, LDH, hsCRP, and ferritin can be used to differentiate patients with and without COVID-19 and as a tool for diagnosis of suspected COVID-19 in adult patients at hospital admission.

Genotype/phenotype relationship in Gaucher disease patients. Novel mutation in glucocerebrosidase gene.

Objectives Gaucher disease (GD) is the most common inherited lysosomal storage disease, caused by mutations in acid ß-glucosidase (GBA) gene. This study aimed to identify mutations in Andalusia patients with GD and their genotype-phenotype correlation. Methods Descriptive observational study. University Hospital Virgen del Rocio patients diagnosed from GD from 1999 to 2019 were included. Demographic and clinical data, ß-glucocerebrosidase activity, variants pathogenic in GBA gene and biomarkers for monitoring treatment were collected from digital medical record. Results Twenty-six patients with aged between 1 day and 52 years were studied. A total of six mutations described as pathogenic and one mutation not described above [c.937T>C (p.Tyr313His)] were identified in the GBA gene, four patients were homozygotes and 22 compound heterozygotes. Twenty-four patients were diagnosed in non-neuropathic form (type 1) and two cases presented neurological involvement (type 2 or 3). The most common variant was c.1226A>G (p.Asn409Ser), which was detected in 24 patients, followed by c.1448T>C (p.Leu483Pro) variant, identified in 13 patients. The c.1448T>C (p.Leu483Pro) mutation has been presented in the most severe phenotypes with neurological involvement associated with type 2 and 3 GD, while c.1226A>G (p.Asn409Ser) mutation has not been associated with neurological alterations. Splenomegaly and bone disease were the most frequent clinical manifestations, and thrombocytopenia was the most common hematological disorder. Conclusions The c.1226A>G (p.Asn409Ser) and c.1448T>C (p.Leu483Pro) mutations were the most common. The c.937T>C (p.Tyr313His) was identified as a novel mutation. The c.1448T>C (p.Leu483Pro) mutation was associated with neurological alterations and c.1226A>G (p.Asn409Ser) mutation has not been associated it.

Influencia del sexo fetal en los marcadores de riesgo utilizados en el cribado prenatal de trisomía 21 / Influence of the gender of the foetus on risk markers used in the prenatal screening of trisomy 21

Introducción. En el cribado combinado de primer trimestre se emplean marcadores bioquímicos y ecográficos que se ven modificados por distintos factores, como peso, gemelaridad, tabaquismo, etc. El objetivo de este estudio es analizar la influencia del sexo fetal en estos marcadores y la repercusión en el resultado del cribado de trisomía 21. Material y métodos. Estudio observacional, descriptivo y retrospectivo (2013-2015). Se excluyeron las gestaciones múltiples. Variables analizadas: medición de la translucencia nucal, la concentración de gonadotropina coriónica humana libre, la proteína plasmática A asociada al embarazo y sus correspondientes múltiplos de la mediana corregidos. Se comparan las medianas de las variables en gestaciones con feto masculino y femenino, afectas y no afectas. Resultados. Incremento del 23,62% en la mediana del múltiplo de la mediana de la gonadotropina coriónica humana libre corregido y del 3,65% en la mediana del múltiplo de la mediana de la proteína plasmática A asociada al embarazo corregido en gestaciones con fetos femeninos. Este aumento se cumple tanto en gestaciones con feto afecto como no afecto de trisomía 21. Sexo masculino: tasa de detección 86,9%, tasa de falsos positivos 3,36%. Sexo femenino: tasa de detección 90,9%, tasa de falsos positivos 4,10%. Conclusiones. El incremento sobre todo de los niveles de gonadotropina coriónica humana libre origina un aumento de la tasa de detección y de la tasa de falsos positivos en gestaciones con feto femenino. La aplicación de un factor de corrección por sexo requiere de estudios coste-efectividad

Introduction. In first trimester combined screening, biochemical and ultrasound markers are used that are modified by different factors such as weight, twins, smoking, etc. The aim of this study is to analyse the influence of foetal gender on these markers, and the repercussion on the result of the screening of trisomy 21. Material and methods. An observational, descriptive and retrospective study (2013-2015) was conducted. Multiple gestations were excluded. Variables analysed: nuchal translucency, free human chorionic gonadotrophin concentration, pregnancy-associated plasma protein A, and their median corrected multiples. A comparison was made of the medians of the variables in gestations with male and female foetuses, affected and non-affected. Results. There was a 23.62% increase in the median of the median corrected multiple free human chorionic gonadotrophin and 3.65% in the median of the median corrected multiple pregnancy-associated plasma protein A, in gestations with female foetuses. This increase is observed in gestations with foetuses affected and non-affected by trisomy 21. Male gender: detection rate 86.9%, false positive rate 3.36%. Female gender: detection rate 90.9%, false positive rate 4.10%. Conclusions. The increase, especially in free human chorionic gonadotrophin levels, leads to an increase in detection rate and false positive rate in gestations with a female foetus. The application of a correction factor by gender requires cost-effectiveness studies

Utilidad del estudio de la actividad antibiótica por bioensayo en el manejo de los derrames pleurales / Usefulness of the measurement of antibiotic activity by bioassay in the management of pleural effusions

Objetivo. El objetivo de este estudio fue determinar la presencia de actividad antibiótica en las muestras de líquido pleural remitidas para estudio y valorar su posible influencia en el manejo clínico de los pacientes. Material y métodos. Estudio observacional y prospectivo que incluyó 81 muestras de líquidos pleurales remitidas al Servicio de Bioquímica del Hospital Universitario de Valme. El estudio de la actividad antibiótica se realizó por bioensayo con base en las recomendaciones del proyecto Pneumonia Etiology Research for Child Health. A todas las muestras se les realizó estudio bioquímico, citológico y bacteriológico con base en técnicas convencionales. Adicionalmente, el uso previo de antibióticos fue evaluado a partir de lo registrado en la historia clínica. Resultados. De los 81 líquidos estudiados, en 26 (32,1%) se constató uso previo de antibióticos a la toma de la muestra según lo registrado en la historia clínica y en 23 (28,4%) existía actividad antibiótica por bioensayo. La actividad antibiótica fue detectada en 15 (62,5%) de los exudados y en 8 (19%) de los trasudados, con una mediana de halos de inhibición de 17mm (rango: 11-22mm). Los 23 líquidos en los que se detectó actividad antibiótica dieron todos cultivo negativo. Conclusiones. Los resultados de este estudio demuestran un alto porcentaje de uso de antibióticos previo al cultivo (32,1%). La evaluación de la actividad antibacteriana del líquido pleural mediante bioensayo paralelamente al cultivo podría ayudar a enfocar el tratamiento y, con base en los parámetros bioquímicos y citológicos, su adecuación (AU)

Objective. The aim of this study was to determine the presence of antibiotic activity in the pleural fluid samples submitted to the laboratory for study, and to assess its possible influence on the clinical management of patients. Material and methods. An observational and prognostic study that included 81 samples of pleural fluid sent to the Biochemistry Department of Valme University Hospital, Seville, Spain. The study of antibiotic activity was performed by bioassay based on the recommendations of the Pneumonia Aetiology Research for Child Health project. All samples were subjected to a biochemical, cytological, and bacteriological study based on conventional techniques. In addition, previous use of antibiotics was evaluated based on what was recorded in the medical records. Results. Based on the medical records, it was observed that 26 (32.1%) of the 81 fluids studied had previous use of antibiotics, with 23 (28.4%) showing antibiotic activity by bioassay. Antibiotic activity was detected in 15 (62.5%) of the exudates and in 8 (19%) of the transudates, with a median inhibition zone of 17mm (range: 11-22mm). In the 23 fluids in which antibiotic activity was detected, all had negative cultures. Conclusions. The results of this study demonstrate a high percentage of previous use of antibiotics prior to culture (32.1%). The evaluation of the antibacterial activity by bioassay in the pleural fluid parallel to bacteriological culture could help in the treatment approach, using the biochemical and cytological parameters to assess its suitability (AU)