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[Abstract] The incidence of colorectal cancer (CRC) has increased worldwide, and early diagnosis is crucial to reduce mortality rates. Therefore, new noninvasive biomarkers for CRC are required. Recent studies have revealed an imbalance in the oral and gut microbiomes of patients with CRC, as well as impaired gut vascular barrier function. In the present study, the microbiomes of saliva, crevicular fluid, feces, and non-neoplastic and tumor intestinal tissue samples of 93 CRC patients and 30 healthy individuals without digestive disorders (non-CRC) were analyzed by 16S rRNA metabarcoding procedures. The data revealed that Parvimonas, Fusobacterium, and Bacteroides fragilis were significantly over-represented in stool samples of CRC patients, whereas Faecalibacterium and Blautia were significantly over-abundant in the non-CRC group. Moreover, the tumor samples were enriched in well-known periodontal anaerobes, including Fusobacterium, Parvimonas, Peptostreptococcus, Porphyromonas, and Prevotella. Co-occurrence patterns of these oral microorganisms were observed in the subgingival pocket and in the tumor tissues of CRC patients, where they also correlated with other gut microbes, such as Hungatella. This study provides new evidence that oral pathobionts, normally located in subgingival pockets, can migrate to the colon and probably aggregate with aerobic bacteria, forming synergistic consortia. Furthermore, we suggest that the group composed of Fusobacterium, Parvimonas, Bacteroides, and Faecalibacterium could be used to design an excellent noninvasive fecal test for the early diagnosis of CRC. The combination of these four genera would significantly improve the reliability of a discriminatory test with respect to others that use a single species as a unique CRC biomarker.

The dynamics of SARS-CoV-2 transmission are influenced by a variety of factors, including social restrictions and the emergence of distinct variants. In this study, we delve into the origins and dissemination of the Alpha, Delta, and Omicron variants of concern in Galicia, northwest Spain. For this, we leveraged genomic data collected by the EPICOVIGAL Consortium and from the GISAID database, along with mobility information from other Spanish regions and foreign countries. Our analysis indicates that initial introductions during the Alpha phase were predominantly from other Spanish regions and France. However, as the pandemic progressed, introductions from Portugal and the USA became increasingly significant. Notably, Galicia’s major coastal cities emerged as critical hubs for viral transmission, highlighting their role in sustaining and spreading the virus. This research emphasizes the critical role of regional connectivity in the spread of SARS-CoV-2 and offers essential insights for enhancing public health strategies and surveillance measures.

[Abstract] Oral and intestinal samples from a cohort of 93 colorectal cancer (CRC) patients and 30 healthy controls (non-CRC) were collected for microbiome analysis. Saliva (28 non-CRC and 94 CRC), feces (30 non-CRC and 97 CRC), subgingival fluid (20 CRC), and tumor tissue samples (20 CRC) were used for 16S metabarcoding and/or RNA sequencing (RNAseq) approaches. A differential analysis of the abundance, performed with the ANCOM-BC package, adjusting the P-values by the Holm-Bonferroni method, revealed that Parvimonas was significantly over-represented in feces from CRC patients (P-value < 0.001) compared to healthy controls. A total of 11 Parvimonas micra isolates were obtained from the oral cavity and adenocarcinoma of CRC patients. Genome analysis identified a pair of isolates from the same patient that shared 99.2% identity, demonstrating that P. micra can translocate from the subgingival cavity to the gut. The data suggest that P. micra could migrate in a synergistic consortium with other periodontal bacteria. Metatranscriptomics confirmed that oral bacteria were more active in tumor than in non-neoplastic tissues. We suggest that P. micra could be considered as a CRC biomarker detected in non-invasive samples such as feces.

[Abstract] Wastewater-based epidemiology (WBE) has become an effective tool in the surveillance of infectious diseases such as COVID-19. In this work, we performed a brief study of monitoring the SARS-CoV-2 viral load in wastewater from six nursing homes located in the metropolitan area of A Coruña (Spain) between December 2020 and March 2021. The main objective was to detect SARSCoV- 2 outbreaks among residents and study the efficacy of the vaccination campaign. SARS-CoV-2 viral load (RNA copies per L of wastewater) was determined by reverse-transcription quantitative PCR (RT-qPCR) using the quantification cycle (Cq) values for the nucleocapsid (N) gene. Our results showed that the increase in viral load preceded the increase in clinical cases, favoring an early warning system that detects COVID-19 outbreaks in advance, making it possible to contain and stop the transmission of the virus among residents. In addition, the efficacy of the new COVID-19 vaccines was evidenced, since after the vaccination campaign in nursing homes in A Coruña, it was observed that many residents did not present any symptoms of the disease, although they excreted high amounts of virus in their feces. WBE is a cost-effective strategy that should be implemented in all cities to prevent new emerging diseases or future pandemic threats.

[Resumen] El microbioma humano desempeña un papel esencial en el mantenimiento de las funciones fisiológicas normales. Estudios previos han demostrado la implicación del microbioma en el desarrollo de patologías, tales como el cáncer colorrectal (CCR). En el presente trabajo, se describió el bacterioma de muestras de saliva, fluído crevicular, heces y tejidos de tumores primarios y de metastásis, procedentes de una cohorte de 93 pacientes de CCR, mediante tecnologías de secuenciación de próxima generación. Los resultados obtenidos se compararon con el bacterioma de muestras de individuos sin CCR, con el objetivo principal de comprender la implicación de las bacterias en el desarrollo del CCR. Los resultados mostraron que el microbioma intestinal de pacientes de CCR estaba desequilibrado y enriquecido en patógenos periodontales. Una combinación específica de estos patógenos orales, ausentes en muestras de personas sin CCR, se propone para su uso como biomarcador para el diagnóstico de CCR empleando muestras no invasivas (heces). Uno de estos patógenos, Parvimonas micra, detectado en la cavidad oral y en carcinomas colorrectales, fue estudiado en profundidad, en una cohorte aleatoria de 20 pacientes, demostrándose mediante genómica comparativa, que esta bacteria es capaz de translocarse desde la cavidad subgingival hasta el colon, formando consorcios sinérgicos con otras bacterias., [Resumo] O microbioma humán desempeña un papel esencial no mantemento das funcións fisiolóxicas normais. Estudos previos demostraron a implicación do microbioma no desenvolvemento de diversas patoloxías, tales como o cancro colorrectal (CCR). No presente traballo, describiuse o bacterioma de mostras de saliva, fluído crevicular xinxival, feces e tecidos de tumores primarios e de metastásis, procedentes dunha cohorte de 93 pacientes de CCR, mediante tecnoloxías de secuenciación de próxima xeración. Os resultados obtidos comparáronse co bacterioma de mostras de individuos sen CCR, co obxectivo principal de comprender a implicación das bacterias no desenvolvemento do CCR. Os resultados mostraron que o microbioma intestinal de pacientes con CCR estaba desequilibrado e enriquecido en patóxenos periodontais. Unha combinación específica destes patóxenos orais, ausentes en mostras de persoas sen CCR, proponse para o seu emprego como biomarcador para o diagnóstico de CCR empregando mostras non invasivas (feces). Un destes patógenos, Parvimonas micra, detectado na cavidade oral e nos carcinomas colorrectais, foi estudado en profundidade nunha cohorte aleatoria de 20 pacientes, demostrándose, mediante xenómica comparativa, que esta bacteria é capaz de translocarse desde a cavidade subxinxival ata o colon, formando consorcios sinérxicos con outras bacterias., [Abstract] The human microbiome plays an essential role in maintaining normal physiological functions. Previous studies have demonstrated its involvement in the development of different diseases such as colorectal cancer (CCR). This study used next-generation sequencing technologies to characterize the bacteriome of saliva, gingival crevicular fluid, feces, primary tumor tissues, and metastatic tissues from a cohort of 93 CRC patients. The results obtained were compared with bacteriome profiles of samples from a group of individuals without CCR, with the main objective of understanding the role of oral and gut bacteria in the CCR development. The findings revealed an imbalanced and a periodontal pathogen-enrichment in the intestinal microbiome of CCR patients. Notably, a specific combination of oral pathogens, absent in no CCR individuals, was identified as a potential biomarker for non-invasive CCR diagnosis using fecal samples. Among these pathogens, Parvimonas micra, detected in the oral cavity and in colorectal carcinomas, was extensively studied in a randomized cohort of 20 CCR patients. Comparative genome analysis demonstrated that this bacterium was able to translocate from the subgingival cavity to the colon forming synergistic consortia with other oral bacteria.

[Abstract] In the day-to-day work of bioinformatics, the use of integrated software packages, which encompass a wide range of tools, enables the development of pipelines for omics data analysis. Within the various existing pipelines, we focus on the analysis of the 16S rRNA gene as it allows for the study of diversity and taxonomy of prokaryotic microorganisms such as Bacteria and Archaea. However, these pipelines often involve a sequence of multiple tools that require intermediate steps before further processing can proceed, as in the case between Cutadapt and DADA2. In fact, in a typical pipeline, the values for DADA2 input arguments ’trunc-len-f’ and ’trunc-len-r’ are extracted from the output of Cutadapt. The best approach for selecting optimal values (aka the trimming positions) is graphically visualizing Cutadapt output and manually selecting the most accurate trimming position length. Therefore, we propose the automation of this specific intermediate step between Cutadapt and DADA2 tools, by selecting values displayed in the graphs that meet the filtering criteria. This automation has been incorporated into a custom pipeline for the analysis of the microbiome in 16S paired-end samples from colorectal cancer patients, and could potentially serve as a standardization approach in these processes

[Abstract] In the last decades, personalized medicine has been increasing its presence in different fields of medicine, including ophthalmology. A new factor that can help us direct medicine towards the challenge of personalized treatments is the microbiome. The gut microbiome plays an important role in controlling immune response, and dysbiosis has been associated with immune-mediated diseases such as non-infectious uveitis (NIU). In this review, we gather the published evidence, both in the pre-clinical and clinical studies, that support the possible role of intestinal dysbiosis in the pathogenesis of NIU, as well as the modulation of the gut microbiota as a new possible therapeutic target. We describe the different mechanisms that have been proposed to involve dysbiosis in the causality of NIU, as well as the potential pharmacological tools that could be used to modify the microbiome (dietary supplementation, antibiotics, fecal microbiota transplantation, immunomodulators, or biologic drugs) and, consequently, in the control of the NIU. Furthermore, there is increasing scientific evidence suggesting that the treatment with anti-TNF not only restores the composition of the gut microbiota but also that the study of the composition of the gut microbiome will help predict the response of each patient to anti-TNF treatment.

[Abstract] The quantification of the SARS-CoV-2 RNA load in wastewater has emerged as a useful tool to monitor COVID–19 outbreaks in the community. This approach was implemented in the metropolitan area of A Coruña (NW Spain), where wastewater from a treatment plant was analyzed to track the epidemic dynamics in a population of 369,098 inhabitants. Viral load detected in the wastewater and the epidemiological data from A Coruña health system served as main sources for statistical models developing. Regression models described here allowed us to estimate the number of infected people (R2 = 0.9), including symptomatic and asymptomatic individuals. These models have helped to understand the real magnitude of the epidemic in a population at any given time and have been used as an effective early warning tool for predicting outbreaks in A Coruña municipality. The methodology of the present work could be used to develop a similar wastewater-based epidemiological model to track the evolution of the COVID–19 epidemic anywhere in the world where centralized water-based sanitation systems exist.

[Abstract] The discovery of new antibiotics that are effective against Acinetobacter baumannii and Enterobacteralesis a research priority. Several essential oils (EOs) have displayed some antimicrobial activity and could potentially act as antibiotic adjuvants. Research in this area aims to develop new therapeutic alternatives to treat infections caused by these pathogens. MICs of different EOs were determined against A. baumannii and Klebsiella pneumoniae. Combined disk diffusion tests and checkerboard assays were used to study the synergy between the EOs and antibiotics. The fractional inhibitory concentration index (FICindex) was calculated in order to categorize the interaction. Time-kill assays were also performed. The EOs that displayed the highest levels of antimicrobial activity were clove (Syzygium aromaticum L.) and thyme (Thymus zygis L.). Combined disk diffusion tests and checkerboard assays revealed synergy between these EOs and colistin. Addition of either clove or thyme EO decreased the MIC of colistin by 8- to 64-fold and 8- to 128-fold in the colistin-resistant A. baumannii and K. pneumoniae strains, respectively (FICindex ≤ 0.5, synergy). MICs were also reduced in the colistin-susceptible strains. Time-kill assays also indicated the strong activity of the combined therapy. In summary, the use of clove or thyme EO in combination with colistin could improve the efficacy of the antibiotic and significantly reduce the concentrations needed to inhibit growth of A. baumannii and K. pneumoniae.

[Abstract] Acinetobacter baumannii is currently considered one of themost problematic nosocomial microorganisms. In the present work the hisF gene from the ATCC 17978 strain and the AbH12O-A2 clinical isolate of A. baumannii was found over-expressed during the course of murine pneumonia infections. The study demonstrated that the A. baumannii ATCC 17978 mutant strain lacking the hisF gene induces a sub-lethal pneumonia infection in mice, while the complemented mutant strain increased its virulence. This histidine auxotroph mutant showed an increase on IL-6 secretion and leukocytes recruitment during infections. Furthermore, data revealed that the hisF gene, implicated in the innate immunity and inflammation, is involved in virulence during a pneumonia infection, which may partly explain the ability of this strain to persist in the lung. We suggest that HisF, essential for full virulence in this pathogen, should be considered a potential target for developing new antimicrobial therapies against A. baumannii.