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Frontiers in Cellular and Infection... 2024We assessed the anti-chlamydial activity of fresh vaginal secretions, deciphering the microbial and metabolic components able to counteract viability.
INTRODUCTION
We assessed the anti-chlamydial activity of fresh vaginal secretions, deciphering the microbial and metabolic components able to counteract viability.
METHODS
Forty vaginal samples were collected from a group of reproductive-aged women and their anti-chlamydial activity was evaluated by inhibition experiments. Each sample underwent 16S rRNA metabarcoding sequencing to determine the bacterial composition, as well as H-NMR spectroscopy to detect and quantify the presence of vaginal metabolites.
RESULTS
Samples characterized by a high anti-chlamydial activity were enriched in , especially and , while not-active samples exhibited a significant reduction of lactobacilli, along with higher relative abundances of and . showed an opposite behavior compared to , being more prevalent in not-active vaginal samples. Higher concentrations of several amino acids (i.e., isoleucine, leucine, and aspartate; positively correlated to the abundance of and ) lactate, and 4-aminobutyrate were the most significant metabolic fingerprints of highly active samples. Acetate and formate concentrations, on the other hand, were related to the abundances of a group of anaerobic opportunistic bacteria (including and ). Finally, glucose, correlated to and genera, emerged as a key molecule of the vaginal environment: indeed, the anti-chlamydial effect of vaginal fluids decreased as glucose concentrations increased.
DISCUSSION
These findings could pave the way for novel strategies in the prevention and treatment of chlamydial urogenital infections, such as lactobacilli probiotic formulations or lactobacilli-derived postbiotics.
Topics: Female; Humans; Vagina; RNA, Ribosomal, 16S; Lactobacillus; Chlamydia trachomatis; Adult; Streptococcus; Young Adult; Lactobacillus crispatus; Chlamydia Infections
PubMed: 38912205
DOI: 10.3389/fcimb.2024.1403782 -
The Lancet. Microbe Jun 2024Microbiota alterations are common in patients hospitalised for severe infections, and preclinical models have shown that anaerobic butyrate-producing gut bacteria...
Association between butyrate-producing gut bacteria and the risk of infectious disease hospitalisation: results from two observational, population-based microbiome studies.
BACKGROUND
Microbiota alterations are common in patients hospitalised for severe infections, and preclinical models have shown that anaerobic butyrate-producing gut bacteria protect against systemic infections. However, the relationship between microbiota disruptions and increased susceptibility to severe infections in humans remains unclear. We investigated the relationship between gut microbiota and the risk of future infection-related hospitalisation in two large population-based cohorts.
METHODS
In this observational microbiome study, gut microbiota were characterised using 16S rRNA gene sequencing in independent population-based cohorts from the Netherlands (HELIUS study; derivation cohort) and Finland (FINRISK 2002 study; validation cohort). HELIUS was conducted in Amsterdam, Netherlands, and included adults (aged 18-70 years at inclusion) who were randomly sampled from the municipality register of Amsterdam. FINRISK 2002 was conducted in six regions in Finland and is a population survey that included a random sample of adults (aged 25-74 years). In both cohorts, participants completed questionnaires, underwent a physical examination, and provided a faecal sample at inclusion (Jan 3, 2013, to Nov 27, 2015, for HELIUS participants and Jan 21 to April 19, 2002, for FINRISK participants. For inclusion in our study, a faecal sample needed to be provided and successfully sequenced, and national registry data needed to be available. Primary predictor variables were microbiota composition, diversity, and relative abundance of butyrate-producing bacteria. Our primary outcome was hospitalisation or mortality due to any infectious disease during 5-7-year follow-up after faecal sample collection, based on national registry data. We examined associations between microbiota and infection risk using microbial ecology and Cox proportional hazards.
FINDINGS
We profiled gut microbiota from 10 699 participants (4248 [39·7%] from the derivation cohort and 6451 [60·3%] from the validation cohort). 602 (5·6%) participants (152 [3·6%] from the derivation cohort; 450 [7·0%] from the validation cohort) were hospitalised or died due to infections during follow-up. Gut microbiota composition of these participants differed from those without hospitalisation for infections (derivation p=0·041; validation p=0·0002). Specifically, higher relative abundance of butyrate-producing bacteria was associated with a reduced risk of hospitalisation for infections (derivation cohort cause-specific hazard ratio 0·75 [95% CI 0·60-0·94] per 10% increase in butyrate producers, p=0·013; validation cohort 0·86 [0·77-0·96] per 10% increase, p=0·0077). These associations remained unchanged following adjustment for demographics, lifestyle, antibiotic exposure, and comorbidities.
INTERPRETATION
Gut microbiota composition, specifically colonisation with butyrate-producing bacteria, was associated with protection against hospitalisation for infectious diseases in the general population across two independent European cohorts. Further studies should investigate whether modulation of the microbiome can reduce the risk of severe infections.
FUNDING
Amsterdam UMC, Porticus, National Institutes of Health, Netherlands Organisation for Health Research and Development (ZonMw), and Leducq Foundation.
PubMed: 38909617
DOI: 10.1016/S2666-5247(24)00079-X -
Nature Communications Jun 2024Lacustrine methane emissions are strongly mitigated by aerobic methane-oxidizing bacteria (MOB) that are typically most active at the oxic-anoxic interface. Although...
Lacustrine methane emissions are strongly mitigated by aerobic methane-oxidizing bacteria (MOB) that are typically most active at the oxic-anoxic interface. Although oxygen is required by the MOB for the first step of methane oxidation, their occurrence in anoxic lake waters has raised the possibility that they are capable of oxidizing methane further anaerobically. Here, we investigate the activity and growth of MOB in Lake Zug, a permanently stratified freshwater lake. The rates of anaerobic methane oxidation in the anoxic hypolimnion reached up to 0.2 µM d. Single-cell nanoSIMS measurements, together with metagenomic and metatranscriptomic analyses, linked the measured rates to MOB of the order Methylococcales. Interestingly, their methane assimilation activity was similar under hypoxic and anoxic conditions. Our data suggest that these MOB use fermentation-based methanotrophy as well as denitrification under anoxic conditions, thus offering an explanation for their widespread presence in anoxic habitats such as stratified water columns. Thus, the methane sink capacity of anoxic basins may have been underestimated by not accounting for the anaerobic MOB activity.
Topics: Methane; Lakes; Oxidation-Reduction; Anaerobiosis; Methylococcaceae; Metagenomics; Oxygen
PubMed: 38906896
DOI: 10.1038/s41467-024-49602-5 -
Chemosphere Jun 2024Four different end-of-life options for disposable bioplastic cups were investigated and compared based on their environmental implications. Two products with distinct...
Four different end-of-life options for disposable bioplastic cups were investigated and compared based on their environmental implications. Two products with distinct polymeric composition were tested simulating the following scenarios at laboratory scale: i) industrial composting (180 days at 58 °C); ii) anaerobic digestion followed by industrial composting (45 days at 55 °C and 180 days at 58 °C); iii) anaerobic digestion followed by direct digestate use on soil for agricultural purposes (45 days at 55 °C and 180 days at 25 °C); iv) uncontrolled release into a soil environment (180 days at 25 °C). Ecotoxicity tests were run at the end of each experiment to investigate the effects of the materials on three main groups of terrestrial model organisms: plants, earthworms and nitrifying bacteria. Complete biodegradation of the cups was observed in 180 days in the scenarios involving composting environment. A low degree of biodegradation (22.9 ± 4.5%) of the digestates in soil was observed, warning for a potential micro-bioplastics discharge into the environment. No degradation was observed for the cups in soil during the same testing period. Ecotoxicity tests revealed a negative effect on plants biomass growth across all samples, which was 17-30% lower compared to the blank sample. The experimental campaign highlighted the need for a systematic assessment of controlled treatment of bioplastics, as well as the need for a harmonized legislative framework.
PubMed: 38906189
DOI: 10.1016/j.chemosphere.2024.142648 -
Microbiology Spectrum Jun 2024The rapid expansion of antibiotic-resistant bacterial diseases is a global burden on public health. It makes sense to repurpose and reposition already-approved...
The rapid expansion of antibiotic-resistant bacterial diseases is a global burden on public health. It makes sense to repurpose and reposition already-approved medications for use as supplementary agents in synergistic combinations with existing antibiotics. Here, we demonstrate that the anthelmintic drug nitazoxanide (NTZ) synergistically enhances the effectiveness of the lipopeptide antibiotic polymyxin B in inhibiting gram-negative bacteria, including those resistant to polymyxin B. Mechanistic investigations revealed that nitazoxanide inhibited calcium influx and cell membrane depolarization, enhanced the affinity between polymyxin B and the extracellular membrane, and promoted intracellular ATP depletion and an increase in reactive oxygen species (ROS), thus enhancing the penetration and disruption of the cell membrane by polymyxin B. The transcriptomic analysis revealed that the combination resulted in energy depletion by inhibiting both aerobic and anaerobic respiration patterns in bacterial cells. The increased bactericidal effect of polymyxin B on the strain further indicates that NuoC could be a promising target for nitazoxanide. Furthermore, the combination of nitazoxanide and polymyxin B showed promising therapeutic effects in a mouse infection model infected with . Taken together, these results demonstrate the potential of nitazoxanide as a novel adjuvant to polymyxin B, to overcome antibiotic resistance and improve therapeutic outcomes in refractory infections.IMPORTANCEThe rapid spread of antibiotic-resistant bacteria poses a serious threat to public health. The search for potential compounds that can increase the antibacterial activity of existing antibiotics is a promising strategy for addressing this issue. Here, the synergistic activity of the FDA-approved agent nitazoxanide (NTZ) combined with polymyxin B was investigated using checkerboard assays and time-kill curves. The synergistic mechanisms of the combination of nitazoxanide and polymyxin B were explored by fluorescent dye, transmission electron microscopy (TEM), and transcriptomic analysis. The synergistic efficacy was evaluated by the and mouse sepsis models. These results suggested that nitazoxanide, as a promising antibiotic adjuvant, can effectively enhance polymyxin B activity, providing a potential strategy for treating multidrug-resistant bacteria.
PubMed: 38904380
DOI: 10.1128/spectrum.00191-24 -
Microbiology Spectrum Jun 2024We examined the microbial populations present in fecal samples of macropods capable of utilizing a mixture of hydrogen and carbon dioxide (70:30) percent. The feces...
UNLABELLED
We examined the microbial populations present in fecal samples of macropods capable of utilizing a mixture of hydrogen and carbon dioxide (70:30) percent. The feces samples were cultured under anaerobic conditions, and production of methane or acetic acids characteristic for methanogenesis and homoacetogenesis was measured. While the feces of adult macropods mainly produced methane from the substrate, the sample from a 2-month-old juvenile kangaroo only produced acetic acid and no methane. The stable highly enriched culture of the joey kangaroo was sequenced to examine the V3 and V4 regions of the 16S rRNA gene. The results showed that over 70% of gene copies belonged to the Clostridia class, with and as the most predominant genera. The culture further showed the presence of spp., a genus which has only been identified in the GI tract of macropods in a few studies, and where none, to our knowledge, have been classified as homoacetogenic. The joey kangaroo mixed culture showed a doubling time of 3.54 h and a specific growth rate of 0.199/h, faster than what has been observed for homoacetogenic bacteria in general.
IMPORTANCE
Enteric methane emissions from cattle are a significant contributor to greenhouse gas emissions worldwide. Methane emissions not only contribute to climate change but also represent a loss of energy from the animal's diet. However, methanogens play an important role as hydrogen sink to rumen systems; without it, the performance of hydrolytic organisms diminishes. Therefore, effective strategies of methanogen inhibition would be enhanced in conjunction with the addition of alternative hydrogen sinks to the rumen. The significance of our research is to identify homoacetogens present in the GI tract of kangaroos and to present their performance , demonstrating their capability to serve as alternatives to rumen methanogens.
PubMed: 38904373
DOI: 10.1128/spectrum.03183-23 -
Biotechnology For Biofuels and... Jun 2024The holistic characterization of different microbiomes in anaerobic digestion (AD) systems can contribute to a better understanding of these systems and provide starting...
BACKGROUND
The holistic characterization of different microbiomes in anaerobic digestion (AD) systems can contribute to a better understanding of these systems and provide starting points for bioengineering. The present study investigates the microbiome of 80 European full-scale AD systems. Operational, chemical and taxonomic data were thoroughly collected, analysed and correlated to identify the main drivers of AD processes.
RESULTS
The present study describes chemical and operational parameters for a broad spectrum of different AD systems. With this data, Spearman correlation and differential abundance analyses were applied to narrow down the role of the individual microorganisms detected. The authors succeeded in further limiting the number of microorganisms in the core microbiome for a broad range of AD systems. Based on 16S rRNA gene amplicon sequencing, MBA03, Proteiniphilum, a member of the family Dethiobacteraceae, the genus Caldicoprobacter and the methanogen Methanosarcina were the most prevalent and abundant organisms identified in all digesters analysed. High ratios for Methanoculleus are often described for agricultural co-digesters. Therefore, it is remarkable that Methanosarcina was surprisingly high in several digesters reaching ratios up to 47.2%. The various statistical analyses revealed that the microorganisms grouped according to different patterns. A purely taxonomic correlation enabled a distinction between an acetoclastic cluster and a hydrogenotrophic one. However, in the multivariate analysis with chemical parameters, the main clusters corresponded to hydrolytic and acidogenic microorganisms, with SAOB bacteria being particularly important in the second group. Including operational parameters resulted in digester-type specific grouping of microbes. Those with separate acidification stood out among the many reactor types due to their unexpected behaviour. Despite maximizing the organic loading rate in the hydrolytic pretreatments, these stages turned into extremely robust methane production units.
CONCLUSIONS
From 80 different AD systems, one of the most holistic data sets is provided. A very distinct formation of microbial clusters was discovered, depending on whether taxonomic, chemical or operational parameters were combined. The microorganisms in the individual clusters were strongly dependent on the respective reference parameters.
PubMed: 38902807
DOI: 10.1186/s13068-024-02525-1 -
NPJ Biofilms and Microbiomes Jun 2024During the COVID-19 pandemic, facemasks played a pivotal role in preventing person-person droplet transmission of viral particles. However, prolonged facemask wearing...
During the COVID-19 pandemic, facemasks played a pivotal role in preventing person-person droplet transmission of viral particles. However, prolonged facemask wearing causes skin irritations colloquially referred to as 'maskne' (mask + acne), which manifests as acne and contact dermatitis and is mostly caused by pathogenic skin microbes. Previous studies revealed that the putative causal microbes were anaerobic bacteria, but the pathogenesis of facemask-associated skin conditions remains poorly defined. We therefore characterized the role of the facemask-associated skin microbiota in the development of maskne using culture-dependent and -independent methodologies. Metagenomic analysis revealed that the majority of the facemask microbiota were anaerobic bacteria that originated from the skin rather than saliva. Previous work demonstrated direct interaction between pathogenic bacteria and antagonistic strains in the microbiome. We expanded this analysis to include indirect interaction between pathogenic bacteria and other indigenous bacteria classified as either 'pathogen helper (PH)' or 'pathogen inhibitor (PIn)' strains. In vitro screening of bacteria isolated from facemasks identified both strains that antagonized and promoted pathogen growth. These data were validated using a mouse skin infection model, where we observed attenuation of symptoms following pathogen infection. Moreover, the inhibitor of pathogen helper (IPH) strain, which did not directly attenuate pathogen growth in vitro and in vivo, functioned to suppress symptom development and pathogen growth indirectly through PH inhibitory antibacterial products such as phenyl lactic acid. Taken together, our study is the first to define a mechanism by which indirect microbiota interactions under facemasks can control symptoms of maskne by suppressing a skin pathogen.
Topics: Animals; Mice; Masks; Microbiota; Humans; COVID-19; Skin; Acne Vulgaris; SARS-CoV-2; Female; Metagenomics; Disease Models, Animal; Bacteria; Microbial Interactions; Dermatitis, Contact
PubMed: 38902263
DOI: 10.1038/s41522-024-00512-w -
BMC Research Notes Jun 2024The need for innovative techniques to preserve microbiota for extended periods, while maintaining the species composition and quantitative balance of the bacterial...
OBJECTIVE
The need for innovative techniques to preserve microbiota for extended periods, while maintaining the species composition and quantitative balance of the bacterial community, is becoming increasingly important. To address this need, we propose an efficient approach to cryopreserve human gut microbiota using a two-component cryoprotective composition comprising fetal bovine serum (FBS) and 5% dimethyl sulfoxide (DMSO). Fetal serum is a commonly utilized component in the freezing media for eukaryotic cells, however, its effects on prokaryotic cells have not been extensively researched.
RESULTS
In our study, we demonstrated the high efficiency of using a two-component cryoprotective medium, FBS + 5% DMSO, for cryopreservation of human gut microbiota using three different methods. According to the obtained results, the intact donor microbiota was preserved at a level of 85 ± 4% of the initial composition based on fluorescent analysis using the LIVE/DEAD test. No differences in survival were observed when comparing with pure DMSO and FBS media. The photometric measurement method for growth of aerobic bacteria (A. johnsoni), facultative anaerobes (E. coli, E. faecalis), microaerophilic (L. plantarum), and obligate anaerobic bacterial cultures (E. barkeri, B. breve) also demonstrated high viability rates of 94-98% in the two-component protective medium, reaching intact control levels. However, for anaerobic microflora representatives, serum proved to be a more suitable cryoprotectant. Also, we demonstrated that using cryoprotective media with 50-75% FBS content is enough to preserve a significant level of bacterial cell viability, from an economic standpoint.
Topics: Cryopreservation; Cryoprotective Agents; Gastrointestinal Microbiome; Humans; Dimethyl Sulfoxide; Animals; Serum; Cattle; Bacteria
PubMed: 38898515
DOI: 10.1186/s13104-024-06836-2 -
Molecules (Basel, Switzerland) Jun 2024Electrocatalytic CO reduction to CO and formate can be coupled to gas fermentation with anaerobic microorganisms. In combination with a competing hydrogen evolution...
Electrocatalytic CO reduction to CO and formate can be coupled to gas fermentation with anaerobic microorganisms. In combination with a competing hydrogen evolution reaction in the cathode in aqueous medium, the in situ, electrocatalytic produced syngas components can be converted by an acetogenic bacterium, such as , into acetate, ethanol, and 2,3-butanediol. In order to study the simultaneous conversion of CO, CO, and formate together with H with , fed-batch processes were conducted with continuous gassing using a fully controlled stirred tank bioreactor. Formate was added continuously, and various initial CO partial pressures (pCO) were applied. utilized CO as the favored substrate for growth and product formation, but below a partial pressure of 30 mbar CO in the bioreactor, a simultaneous CO/H conversion was observed. Formate supplementation enabled 20-50% higher growth rates independent of the partial pressure of CO and improved the acetate and 2,3-butanediol production. Finally, the reaction conditions were identified, allowing the parallel CO, CO, formate, and H consumption with at a limiting CO partial pressure below 30 mbar, pH 5.5, n = 1200 min, and T = 32 °C. Thus, improved carbon and electron conversion is possible to establish efficient and sustainable processes with acetogenic bacteria, as shown in the example of
Topics: Formates; Clostridium; Carbon Monoxide; Hydrogen; Carbon Dioxide; Bioreactors; Butylene Glycols; Fermentation; Gases; Ethanol
PubMed: 38893534
DOI: 10.3390/molecules29112661