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.

Evaluation of the Premier Hb9210 instrument for HbA1c determination.

Background: Glycated hemoglobin measurements are a valuable tool for long-term blood glucose monitoring and the diagnosis of diabetes. Its widespread use has been made possible due to the development of new analytical methods with improved performances and standardization with reference materials. The aim of the present study was to evaluate the Trinity Biotech Premier Hb9210 analyzer for the measurement of HbA1c.Methods: The precision was assessed using the CLSI EP-15A3 and EP-10A3 protocols. The latter was also used to investigate linearity, carryover, and linear drift. The comparison study was performed between Premier Hb910 and Tosoh HLC-723 G8 through Passing-Bablok regression and the Bland-Altman plot. The Fleiss Kappa index was used to assess the degree of agreement. The interference of Hb variants was investigated using samples with Hb variants S, C, D, E, J, and Seville.Results: Within-run and between-run imprecision fell between 0.37% and 1.16%. No statistically significant nonlinearity, carry-over, and/or drift were observed. The resulting regression line of the Passing-Bablok analysis was y = 0.00 + 1.00x. The Pearson correlation coefficient was 0.997. In the Bland-Altman plot, the relative bias was 0.01%. The overall Fleiss Kappa index was 0.9. No interference from hemoglobin variants was observed.Conclusion: The Premier Hb9210 demonstrated a high degree of automation, reproducibility, good agreement, minimal carry-over effect, and excellent linearity across the wide range of HbA1c levels commonly found in diabetic patients and was not influenced by Hb variants.

Premier Hb9210 can be used as an alternative to monitor glycemic status.Premier Hb9210 is not affected by common hemoglobin variants.Premier Hb9210 can correctly classify diabetic patients.

Effect of chemotherapy on urinary volatile biomarkers for lung cancer by HS-SPME-GC-MS and chemometrics.

BACKGROUND: Volatile organic compounds (VOCs) have been studied as possible biomarkers in several diseases, including lung cancer. Early detection of cancer can improve long-term survival rates and the quality of life, so the study of VOCs in exhaled breath and urine has been increasing in recent years. This study aimed to assess the urinary VOCs that are modified after chemotherapy to identify those with the potential to be lung cancer biomarkers that can be monitored during treatment. METHODS: Three urine samples from 10 men with stage IV lung adenocarcinoma were collected, as well as urine samples from 14 men with other types of cancer (control group). All samples were analyzed by headspace-solid phase microextraction gas chromatography coupled with mass spectrometry. RESULTS: A total of 21 urinary VOCs were found with different levels after the administration of chemotherapy, with 2-pentanone being one of those that significantly decreased. Furthermore, 2-pentanone and 3-hydroxy-2,4,4-trimethylpentyl-2-methylpropanoate showed statistically significant differences with the control group. CONCLUSIONS: Chemotherapy administered to patients with advanced lung adenocarcinoma modified the volatile profile of urine. 2-Pentanone, a final product of the increased rate of fatty acid oxidation and protein hypermetabolism, significantly decreased after chemotherapy. Therefore, monitoring its urinary excretion could be very useful since its decrease over time could indicate an adequate response to chemotherapy and arrest of cancer development. Another VOC that could be a potential lung cancer biomarker is 3 hydroxy-2,4,4-trimethylpentyl-2-methylpropanoate, whose origin may be due to inhibition of the propanoic acid metabolic pathway or increased aldehyde dehydrogenase activity.

Feasibility of using volatile urine fingerprints for the differentiation of sexually transmitted infections.

Sexually transmitted infections (STIs) are a public health problem worldwide, and current diagnostic methods have certain limitations. In recent years, volatile organic compounds (VOCs) have been studied as an alternative diagnostic method. Due to this, this study aimed to detect, in vaginal swabs and urine samples, VOCs emitted by highly prevalent STIs-causing bacteria (Chlamydia trachomatis, Mycoplasma genitalium, and Neisseria gonorrhoeae) to identify potential biomarkers that allow the detection of these STIs. VOCs detected in urine samples showed a better differentiation of patients with STIs due to C. trachomatis from those not infected, with 2,6-dimethyl-4-heptanone as the volatile compound most related to the presence of this bacterium. Among the VOCs most related to M. genitalium in urine, 4-methyltetradecane and 2-methylpentadecane stood out, while 3,4,4-trimethyl-2-cyclohexen-1-one was the VOC most closely related to N. gonorrhoeae infection. Moreover, C12 alcohols were the main VOC family associated with positive samples in all three bacteria, which could indicate the presence of aldehyde reductases in their metabolism. In contrast, alcohols such as 3-methyl-1-heptanol and 1-octanol, as well as dimethyl esters, were more associated with negative samples and may be useful in ruling out an STI caused by one of these three bacteria. In short, the VOCs identified as potential biomarkers in patients with infection by C. trachomatis, M. genitalium, or N. gonorrhoeae could be used in the early diagnosis of these STIs, quickly interrupting the chain of transmission, especially interesting in asymptomatic patients. KEY POINTS: • Sexually transmitted infections are a serious public health problem worldwide. • The study of VOCs in multiple infections is increasing in recent years. • The identification of volatile biomarkers could allow new diagnostic methods.

Identification of volatile biomarkers of Trichomonas vaginalis infection in vaginal discharge and urine.

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.

Evaluation of the Congenital Hypothyroidism Detection Strategy in Extremely Preterm Infants in Western Andalusia.

OBJECTIVE: This study aimed to identify extremely premature infants (< 31 weeks of gestation and/or <1,500 g) affected by congenital hypothyroidism (CH) with delayed elevation of thyrotropin (TSH) and to evaluate the detection strategy for this pathology in our reference screening population. STUDY DESIGN: A descriptive and retrospective study was carried out with samples collected from western Andalusia and the autonomous city of Ceuta. RESULTS: This protocol allowed us to detect six neonates with delayed TSH elevation. One of them, due to serious heart problems, died without being able to confirm CH. In two neonates, however, it was possible to detect CH, another two presented a persistent TSH elevation but normal free T4, and another one presented a temporary TSH elevation. CONCLUSION: It is essential to repeat the CH screening in extremely premature infants, not only at the age of 15 days but also with a third sample at the moment of hospital discharge to detect cases with delayed TSH elevation. KEY POINTS: · The Newborn Screening Programs are an essential activity of preventive medicine.. · Extremely preterm infants have a very high risk of CH.. · Optimal management of thyroid dysfunction in this population remains to be established..

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.

Fecal Volatile Organic Compounds and Microbiota Associated with the Progression of Cognitive Impairment in Alzheimer's Disease.

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.

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.

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.