Are the Chicago 3.0 manometric diagnostics consistent with Chicago 4.0?

There is little information on the degree of concordance between the results obtained using the Chicago 3.0 (CCv3.0) and Chicago 4.0 (CCv4.0) protocols to interpret high-resolution manometry (HRM) seeking to determine the value provided by the new swallowing maneuvers included in the last protocol. This is a study of diagnostic tests, evaluating concordance by consistency between the results obtained by the CCv3.0 and CCv4.0 protocols, in patients undergoing HRM. Concordance was assessed with the kappa test. Bland-Altman scatter plots, and Lin's correlation-concordance coefficient (CCC) were used to assess the agreement between IRP measured with swallows in the supine and seated position or with solid swallows. One hundred thirty-two patients were included (65% women, age 53 ± 17 years). The most frequent HRM indication was dysphagia (46.1%). Type I was the most common type of gastroesophageal junction. The most frequent CCv4.0 diagnoses were normal esophageal motility (68.9%), achalasia (15.5%), and ineffective esophageal motility (IEM; 5.3%). The agreement between the results was substantial (Kappa 0.77 ± 0.05), with a total agreement of 87.9%. Diagnostic reclassification occurred in 12.1%, from IEM in CCv3.0 to normal esophageal motility in CCv4.0. Similarly, there was a high level of agreement between the IRP measured in the supine compared to the seated position (CCC0.92) and with solid swallows (CCC0.96). In conclusion, the CCv4.0 protocol presents a high concordance compared to CCv3.0. In the majority of manometric diagnoses there is no reclassification of patients with provocation tests. However, the more restrictive criteria of CCv4.0 achieve a better reclassification of patients with IEM.

Guidance document on the impact of water treatment processes on residues of active substances or their metabolites in water abstracted for the production of drinking water.

This guidance document provides a tiered framework for risk assessors and facilitates risk managers in making decisions concerning the approval of active substances (AS) that are chemicals in plant protection products (PPPs) and biocidal products, and authorisation of the products. Based on the approaches presented in this document, a conclusion can be drawn on the impact of water treatment processes on residues of the AS or its metabolites in surface water and/or groundwater abstracted for the production of drinking water, i.e. the formation of transformation products (TPs). This guidance enables the identification of actual public health concerns from exposure to harmful compounds generated during the processing of water for the production of drinking water, and it focuses on water treatment methods commonly used in the European Union (EU). The tiered framework determines whether residues from PPP use or residues from biocidal product use can be present in water at water abstraction locations. Approaches, including experimental methods, are described that can be used to assess whether harmful TPs may form during water treatment and, if so, how to assess the impact of exposure to these water treatment TPs (tTPs) and other residues including environmental TPs (eTPs) on human and domesticated animal health through the consumption of TPs via drinking water. The types of studies or information that would be required are described while avoiding vertebrate testing as much as possible. The framework integrates the use of weight-of-evidence and, when possible alternative (new approach) methods to avoid as far as possible the need for additional testing.

Chemical characterization and anaerobic treatment of bitumen fume condensate using a membrane bioreactor.

Bitumen fume condensate (BFC) is a hazardous wastewater generated at asphalt reclamation and production sites. BFC contains a wide variety of potentially toxic organic pollutants that negatively affect anaerobic processes. In this study, we chemically characterized BFC produced at an industrial site and evaluated its degradation under anaerobic conditions. Analyses identified about 900 compounds including acetate, polycyclic aromatic hydrocarbons, phenolic compounds, and metal ions. We estimated the half maximal inhibitory concentrations (IC50) of methanogenesis of 120, 224, and 990 mgCOD·L-1 for three types of anaerobic biomass, which indicated the enrichment and adaptation potentials of methanogenic biomass to the wastewater constituents. We operated an AnMBR (7.0 L, 35 °C) for 188 days with a mixture of BFC, phenol, acetate, and nutrients. The reactor showed a maximum average COD removal efficiency of 87.7 ± 7.0 %, that corresponded to an organic conversion rate of 286 ± 71 mgCOD-1·L-1d-1. The microbial characterization of the reactor's biomass showed the acetoclastic methanogen Methanosaeta as the most abundant microorganism (43 %), whereas the aromatic and phenol degrader Syntrophorhabdus was continuously present with abundances up to 11.5 %. The obtained results offer the possibility for the application of AnMBRs for the treatment of BFC or other petrochemical wastewater.

Use of Tenofovir Alafenamide/Emtricitabine/Elvitegravir-Cobicistat in HIV-Naive Patients with Advanced Disease: GENIS Study.

Objective: The primary endpoint of the study was to determine the proportion of patients with HIV RNA < 50 copies/mL at 48 weeks. Design: Phase IV, multicentric, open-label, single-arm clinical trial of participants recruited in 2018−2019 to evaluate the efficacy and safety of tenofovir alafenamide/emtricitabine/elvitegravir-cobicistat (TAF/FTC/EVG-c) as first-line treatment in HIV-1 infected naïve participants with advanced disease. Methods: Adverse events were graded according to the Division of AIDS scale version 2.0. Quantitative variables were recorded as median and interquartile range, and qualitative variables as absolute number and percentage. T-Student or Wilcoxon tests were used to analyze intragroup differences of the continuous variables. Results: Fifty participants were recruited with a baseline median CD4 lymphocyte count of 116 cells/µL and a viral load of 218,938 copies/mL. The proportion of patients with viral load <50 copies/mL at week 48 was 94% in the per-protocol analysis, with a median time of 1.9 months to achieve it. Three adverse events attributed to the study drug caused trial discontinuation. Conclusions: the use of TAF/FTC/EVG-c in patients with advanced HIV disease in our study demonstrated efficacy comparable to data from pivotal clinical trials with a good safety profile.

Coronavirus disease 2019 hospitalization outcomes in persons with and without HIV in Spain.

OBJECTIVE: To compare coronavirus disease 2019 (COVID-19) hospitalization outcomes between persons with and without HIV. DESIGN: Retrospective observational cohort study in 150 hospitals in Spain. METHODS: Patients admitted from 1 March to 8 October 2020 with COVID-19 diagnosis confirmed by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 positive) PCR test in respiratory tract samples. The primary data source was the COVID-19 Sociedad Española de Medicina Interna's registry (SEMI-COVID-19). Demographics, comorbidities, vital signs, laboratory parameters, and clinical severity as well as treatments received during admission, treatment duration, ICU admission, use of invasive mechanical ventilation, and death were recorded. Factors associated with mortality and the composite of ICU admission, invasive mechanical ventilation, and death, were analyzed. RESULTS: Data from 16 563 admissions were collected, 98 (0.59%) of which were of persons with HIV infection. These patients were younger, the percentage of male patients was higher, and their Charlson comorbidity index was also higher. Rates of mortality and composite outcome of ICU admission, invasive mechanical ventilation or death were lower among patients with HIV infection. In the logistic regression analysis, HIV infection was associated with an adjusted odds ratio of 0.53 [95% confidence interval (CI) 0.29-0.96] for the composite outcome. CONCLUSION: HIV infection was associated with a lower probability of ICU admission, invasive mechanical ventilation, or death.

Infecciones abdominales por Actinomyces odontolyticus: comunicación de dos casos

Resumen Actinomyces spp es una familia de bacilos grampositivos saprofíticos que rara vez producen infecciones en el ser humano. Actinomyces odontolyticus forma parte de la microbiota oral y existen escasos reportes de casos de infecciones asociadas a este microorganismo, principalmente de localización oral, torácica, pélvica y bacteremias. Estas infecciones se caracterizan por ser recidivantes y causar abscesos y trayectos fistulosos. Su aislamiento microbiológico es difícil ya que la mayoría de los equipos automatizados no identifican la especie de Actinomyces, por lo que técnicas como MALDI-TOF MS resulta de gran ayuda en el diagnóstico definitivo. Finalmente, el tratamiento antibacteriano debe ser prolongado, acompañado del drenaje quirúrgico de las colecciones. Presentamos dos casos de infección abdominal recurrente por A. odontolyticus, en pacientes inmunocompetentes, con tratamiento exitoso.

Abstract Actinomyces spp is a family of saprophytic gram-positive rods that rarely cause infections in humans. Actinomyces odontolyticus is part of the oral microbiota and there are few case reports of infections associated, mainly oral, thoracic, pelvic involvement and bacteremia. These infections are characterized by being recurrent and causing abscesses and fistulous tracts. Microbiological isolation of the microorganism is difficult because most of the automated identification equipment does not detect the Actinomyces species. The use of identification techniques such as MALDI-TOF MS is a great help in the definitive diagnosis. Finally, antibacterial treatment should be prolonged, and accompanied by surgical drainage of the collections. We report two cases of recurrent abdominal infection by A. odontolyticus, in immunocompetent patients, with successful treatment.

Inadequate use of antibiotics in the covid-19 era: effectiveness of antibiotic therapy.

BACKGROUND: Since December 2019, the COVID-19 pandemic has changed the concept of medicine. This work aims to analyze the use of antibiotics in patients admitted to the hospital due to SARS-CoV-2 infection. METHODS: This work analyzes the use and effectiveness of antibiotics in hospitalized patients with COVID-19 based on data from the SEMI-COVID-19 registry, an initiative to generate knowledge about this disease using data from electronic medical records. Our primary endpoint was all-cause in-hospital mortality according to antibiotic use. The secondary endpoint was the effect of macrolides on mortality. RESULTS: Of 13,932 patients, antibiotics were used in 12,238. The overall death rate was 20.7% and higher among those taking antibiotics (87.8%). Higher mortality was observed with use of all antibiotics (OR 1.40, 95% CI 1.21-1.62; p < .001) except macrolides, which had a higher survival rate (OR 0.70, 95% CI 0.64-0.76; p < .001). The decision to start antibiotics was influenced by presence of increased inflammatory markers and any kind of infiltrate on an x-ray. Patients receiving antibiotics required respiratory support and were transferred to intensive care units more often. CONCLUSIONS: Bacterial co-infection was uncommon among COVID-19 patients, yet use of antibiotics was high. There is insufficient evidence to support widespread use of empiric antibiotics in these patients. Most may not require empiric treatment and if they do, there is promising evidence regarding azithromycin as a potential COVID-19 treatment.

Enhancing Phenol Conversion Rates in Saline Anaerobic Membrane Bioreactor Using Acetate and Butyrate as Additional Carbon and Energy Sources.

Phenolic industrial wastewater, such as those from coal gasification, are considered a challenge for conventional anaerobic wastewater treatment systems because of its extreme characteristics such as presence of recalcitrant compounds, high toxicity, and salinity. However, anaerobic membrane bioreactors (AnMBRs) are considered of potential interest since they retain all micro-organism that are required for conversion of the complex organics. In this study, the degradation of phenol as main carbon and energy source (CES) in AnMBRs at high salinity (8.0 g Na+⋅L-1) was evaluated, as well as the effect of acetate and an acetate-butyrate mixture as additional CES on the specific phenol conversion rate and microbial community structure. Three different experiments in two lab-scale (6.5 L) AnMBRs (35°C) were conducted. The first reactor (R1) was fed with phenol as the main CES, the second reactor was fed with phenol and either acetate [2 g COD⋅L-1], or a 2:1 acetate-butyrate [2 g COD⋅L-1] mixture as additional CES. Results showed that phenol conversion could not be sustained when phenol was the sole CES. In contrast, when the reactor was fed with acetate or an acetate-butyrate mixture, specific phenol conversion rates of 115 and 210 mgPh⋅gVSS-1 d-1, were found, respectively. The syntrophic phenol degrader Syntrophorhabdus sp. and the acetoclastic methanogen Methanosaeta sp. were the dominant bacteria and archaea, respectively, with corresponding relative abundances of up to 63 and 26%. The findings showed that dosage of additional CES allowed the development of a highly active phenol-degrading biomass, potentially improving the treatment of industrial and chemical wastewaters.

Prolonged administration of maraviroc reactivates latent HIV in vivo but it does not prevent antiretroviral-free viral rebound.

Human immunodeficiency virus (HIV) remains incurable due to latent viral reservoirs established in non-activated CD4 T cells that cannot be eliminated via antiretroviral therapy. Current efforts to cure HIV are focused on identifying drugs that will induce viral gene expression in latently infected cells, commonly known as latency reversing agents (LRAs). Some drugs have been shown to reactivate latent HIV but do not cause a reduction in reservoir size. Therefore, finding new LRAs or new combinations or increasing the round of stimulations is needed to cure HIV. However, the effects of these drugs on viral rebound after prolonged treatment have not been evaluated. In a previous clinical trial, antiretroviral therapy intensification with maraviroc for 48 weeks caused an increase in residual viremia and episomal two LTR-DNA circles suggesting that maraviroc could reactivate latent HIV. We amended the initial clinical trial to explore additional virologic parameters in stored samples and to evaluate the time to viral rebound during analytical treatment interruption in three patients. Maraviroc induced an increase in cell-associated HIV RNA during the administration of the drug. However, there was a rapid rebound of viremia after antiretroviral therapy discontinuation. HIV-specific T cell response was slightly enhanced. These results show that maraviroc can reactivate latent HIV in vivo but further studies are required to efficiently reduce the reservoir size.

Anaerobic Conversion of Saline Phenol-Containing Wastewater Under Thermophilic Conditions in a Membrane Bioreactor.

Closing water loops in chemical industries result in hot and highly saline residual streams, often characterized by high strength and the presence of refractory or toxic compounds. These streams are attractive for anaerobic technologies, provided the chemical compounds are biodegradable. However, under such harsh conditions, effective biomass immobilization is difficult, limiting the use of the commonly applied sludge bed reactors. In this study, we assessed the long-term phenol conversion capacity of a lab-scale anaerobic membrane bioreactor (AnMBR) operated at 55°C, and high salinity (18 gNa+.L-1). Over 388 days, bioreactor performance and microbial community dynamics were monitored using specific methanogenic activity (SMA) assays, phenol conversion rate assays, volatile fatty acids permeate characterization and Illumina MiSeq analysis of 16S rRNA gene sequences. Phenol accumulation to concentrations exceeding 600 mgPh.L-1 in the reactor significantly reduced methanogenesis at different phases of operation, while applying a phenol volumetric loading rate of 0.12 gPh.L-1.d-1. Stable AnMBR reactor performance could be attained by applying a sludge phenol loading rate of about 20 mgPh.gVSS-1.d-1. In situ maximum phenol conversion rates of 21.3 mgPh.gVSS-1 .d-1 were achieved, whereas conversion rates of 32.8 mgPh.gVSS-1 .d-1 were assessed in ex situ batch tests at the end of the operation. The absence of caproate as intermediate inferred that the phenol conversion pathway likely occurred via carboxylation to benzoate. Strikingly, the hydrogenotrophic SMA of 0.34 gCOD-CH4 .gVSS-1 .d-1 of the AnMBR biomass significantly exceeded the acetotrophic SMA, which only reached 0.15 gCOD-CH4 .gVSS-1 .d-1. Our results indicated that during the course of the experiment, acetate conversion gradually changed from acetoclastic methanogenesis to acetate oxidation coupled to hydrogenotrophic methanogenesis. Correspondingly, hydrogenotrophic methanogens of the class Methanomicrobia, together with Synergistia, Thermotogae, and Clostridia classes, dominated the microbial community and were enriched during the three phases of operation, while the aceticlastic Methanosaeta species remarkably decreased. Our findings clearly showed that highly saline phenolic wastewaters could be satisfactorily treated in a thermophilic AnMBR and that the specific phenol conversion capacity was limiting the treatment process. The possibility of efficient chemical wastewater treatment under the challenging studied conditions would represent a major breakthrough for the widespread application of AnMBR technology.

Brief Report: CYP27B1 rs10877012 T Allele Was Linked to Non-AIDS Progression in ART-Naïve HIV-Infected Patients: A Retrospective Study.

BACKGROUND: HIV/AIDS progression is linked to vitamin D, which is regulated by several key cytochromes P450 (CYP). Single nucleotide polymorphisms (SNPs) in CYP genes influence vitamin D metabolism and serum levels. The objective of this study was to evaluate the association between CYP SNPs and the clinical AIDS progression in antiretroviral treatment (ART)-naïve HIV-infected patients. METHODS: We performed a retrospective study in 661 ART-naïve HIV-infected patients who were stratified by their AIDS progression pattern [181 long-term nonprogressors (LTNPs), 332 moderate progressors, and 148 rapid progressors (RPs)]. Four CYP SNPs (CYP2R1 rs10500804, CYP2R1 rs1993116, CYP27B1 rs10877012, and CYP24A1 rs6013897) were genotyped using Agena Bioscience's MassARRAY platform. Correction for multiple testing was performed using the false discovery rate (Benjamini-Hochberg procedure). RESULTS: The adjusted regression showed a significant association only for CYP27B1 rs10877012 SNP. When analyzing all HIV patients, the rs10877012 T allele was protective against AIDS progression (ordinal outcome) under the dominant [adjusted odds ratio (aOR) = 0.69; P = 0.021) and additive (aOR) = 0.75; P = 0.025] inheritance models. When analyzing LTNPs versus RPs, the rs10877012 T allele also showed a significant protective association under the dominant (aOR = 0.45; P = 0.004) and additive (aOR = 0.54; P = 0.008) inheritance models. P values remained significant after correcting by multiple comparisons only for the comparison of LTNPs versus RPs (extreme phenotypes). CONCLUSIONS: The CYP27B1 rs10877012 T allele was linked to non-AIDS progression in ART-naïve HIV-infected patients. The rs10877012 SNP seems to have an impact on the clinical AIDS progression, possibly modifying vitamin D levels, which could be relevant for the pathogenesis of HIV infection.

Insulin degludec allows for better glycaemic control with a lower risk of hypoglycaemia in patients with chronic kidney disease and type 2 diabetes.

We conducted a retrospective observational study to demonstrate that switching to insulin degludec from other long-acting insulins reduces the risk of hypoglycaemia events and improves glycaemic control in patients with type 2 diabetes and stage 2-3B chronic kidney disease.

Influence of particle size distribution on anaerobic degradation of phenol and analysis of methanogenic microbial community.

Sludge morphology considerably affects the mechanism underlying microbial anaerobic degradation of phenol. Here, we assessed the phenol degradation rate, specific methanogenic activity, electron transport activity, coenzyme F420 concentration, and microbial community structure of five phenol-degrading sludge of varying particle sizes (i.e., < 20, 20-50, 50-100, 100-200, and > 200 µm). The results indicated an increase in phenol degradation rate and microbial community structure that distinctly correlated with an increase in sludge particle size. Although the sludge with the smallest particle size (< 20 µm) showed the lowest phenol degradation rate (9.3 mg COD·gVSS-1 day-1), its methanogenic activity with propionic acid, butyric acid, and H2/CO2 as substrates was the best, and the concentration of coenzyme F420 was the highest. The small particle size sludge did not contain abundant syntrophic bacteria or hydrogenotrophic methanogens, but contained abundant acetoclastic methanogens. Moreover, the floc sizes of the different sludge varied in important phenol-degrading bacteria and archaea, which may dominate the synergistic mechanism. This study provides a new perspective on the role of sludge floc size on the anaerobic digestion of phenol.

Low-loss pedestal Ta2O5 nonlinear optical waveguides.

In this work, we investigate a pedestal tantalum oxide (Ta2O5) material platform for integrated nonlinear optics (NLO). In order to achieve low propagation losses with this material, pedestal waveguides with Ta2O5 cores were designed. The nonlinear refractive index n2 of this new platform was obtained by measuring the amount of spectral broadening due to self-phase modulation (SPM) of 23 fs optical pulses at 785 nm propagating through the waveguides. In this manner, a nonlinear index of (5.8 ± 2.0) × 10-19 m2W-1 was found for this material, which is in good agreement with values reported in related works where strip waveguides were used for a similar purpose. Furthermore, due to the pedestal configuration, propagation losses as low as 1.6 dB·cm-1 for narrow waveguides and 0.1 dB·cm-1 for large waveguides were obtained. Finite element method (FEM) mode analysis was performed to calculate the mode characteristics, as well as the effective areas of the waveguides. The high nonlinear and linear refractive indices, wide bandgap and low propagation losses make this platform ideal for applications extending from the visible into the mid-IR regions of the optical spectrum. Due the large gap, Ta2O5 should have low two photon absorption at the near-IR as well.

Performance and recovery of a completely separated partial nitritation and anammox process treating phenol-containing wastewater.

Anammox process is considered as a promising technology for removing total nitrogen from low-strength ammonium and phenol-containing wastewater. However, it is still a challenge for the anammox process to treat high-strength ammonium and phenol-containing wastewater. A completely separated partial nitritation and anammox (CSPN/A) process was developed to remove total nitrogen from high-strength phenol-containing wastewater. About 92% of COD, 100% of phenol, and 82.4% of total nitrogen were successfully removed at a NH4+-N concentration of 200 mg L-1 with a phenol/NH4+-N mass ratio of 0.5 in the CSPN/A process. Furthermore, a shock loading of 300 mg phenol L-1 with a phenol/NH4+-N mass ratio of 1.5 led to a complete failure of partial nitritation, but the performance was rapidly recovered by the increase of NH4+-N concentration. Although the activities of ammonium-oxidizing bacteria and anammox bacteria were severely inhibited at a phenol/NH4+-N mass ratio of 1.5, the enrichment of efficient phenol degraders in the CSPN stage could strengthen the performance robustness of partial nitritation and anammox process. Therefore, this study presented a new insight on the feasibility of the anammox process for treating high-strength ammonium and phenol-containing wastewater.

Temperature susceptibility of a mesophilic anaerobic membrane bioreactor treating saline phenol-containing wastewater.

This study examined the temperature susceptibility of a continuous-flow lab-scale anaerobic membrane bioreactor (AnMBR) to temperature shifts from 35 °C to 55 °C and its bioconversion robustness treating synthetic phenolic wastewater at 16 gNa+.L-1. During the experiment, the mesophilic reactor was subjected to stepwise temperature increases by 5 °C. The phenol conversion rates of the AnMBR decreased from 3.16 at 35 °C to 2.10 mgPh.gVSS-1.d-1 at 45 °C, and further decreased to 1.63 mgPh.gVSS-1.d-1 at 50 °C. At 55 °C, phenol conversion rate stabilized at 1.53 mgPh.gVSS-1.d-1 whereas COD removal efficiency was 38% compared to 95.5% at 45 °C and 99.8% at 35 °C. Interestingly, it was found that the phenol degradation process was less susceptible for the upward temperature shifts than the methanogenic process. The temperature increase implied twenty-one operational taxonomic units from the reactor's microbial community with significant differential abundance between mesophilic and thermophilic operation, and eleven of them are known to be involved in aromatic compounds degradation. Reaching the upper-temperature limits for mesophilic operation was associated with the decrease in microbial abundance of the phyla Firmicutes and Proteobacteria, which are linked to syntrophic phenol degradation. It was also found that the particle size decreased from 89.4 µm at 35 °C to 21.0 µm at 55 °C. The accumulation of small particles and higher content of soluble microbial protein-like substances led to increased transmembrane pressure which negatively affected the filtration performance. Our findings indicated that at high salinity a mesophilic AnMBR can tolerate a temperature up to 45 °C without being limited in the phenol conversion capacity.

Impact of long-term salinity exposure in anaerobic membrane bioreactors treating phenolic wastewater: Performance robustness and endured microbial community.

Industrial wastewaters are becoming increasingly associated with extreme conditions such as the presence of refractory compounds and high salinity that adversely affect biomass retention or reduce biological activity. Hence, this study evaluated the impact of long-term salinity increase to 20 gNa+.L-1 on the bioconversion performance and microbial community composition in anaerobic membrane bioreactors treating phenolic wastewater. Phenol removal efficiency of up to 99.9% was achieved at 14 gNa+.L-1. Phenol conversion rates of 5.1 mgPh.gVSS-1.d-1, 4.7 mgPh.gVSS-1.d-1, and 11.7 mgPh.gVSS-1.d-1 were obtained at 16 gNa+.L-1,18 gNa+.L-1 and 20 gNa+.L-1, respectively. The AnMBR's performance was not affected by short-term step-wise salinity fluctuations of 2 gNa+.L-1 in the last phase of the experiment. It was also demonstrated in batch tests that the COD removal and methane production rate were higher at a K+:Na+ ratio of 0.05, indicating the importance of potassium to maintain the methanogenic activity. The salinity increase adversely affected the transmembrane pressure likely due to a particle size decrease from 185 µm at 14 gNa+.L-1 to 16 µm at 20 gNa+.L-1. Microbial community was dominated by bacteria belonging to the Clostridium genus and archaea by Methanobacterium and Methanosaeta genus. Syntrophic phenol degraders, such as Pelotomaculum genus were found to be increased when the maximum phenol conversion rate was attained at 20 gNa+.L-1. Overall, the observed robustness of the AnMBR performance indicated an endured microbial community to salinity changes in the range of the sodium concentrations applied.

Operation-driven heterogeneity and overlooked feed-associated populations in global anaerobic digester microbiome.

Anaerobic digester (AD) microbiomes harbor complex, interacting microbial populations to achieve biomass reduction and biogas production, however how they are influenced by operating conditions and feed sludge microorganisms remain unclear. These were addressed by analyzing the microbial communities of 90 full-scale digesters at 51 municipal wastewater treatment plants from five countries. Heterogeneity detected in community structures suggested that no single AD microbiome could be defined. Instead, the AD microbiomes were classified into eight clusters driven by operating conditions (e.g., pretreatment, temperature range, and salinity), whereas geographic location of the digesters did not have significant impacts. Comparing digesters populations with those present in the corresponding feed sludge led to the identification of a hitherto overlooked feed-associated microbial group (i.e., the residue populations). They accounted for up to 21.4% of total sequences in ADs operated at low temperature, presumably due to ineffective digestion, and as low as 0.8% in ADs with pretreatment. Within each cluster, a core microbiome was defined, including methanogens, syntrophic metabolizers, fermenters, and the newly described residue populations. Our work provides insights into the key factors shaping full-scale AD microbiomes in a global scale, and draws attentions to the overlooked residue populations.