Anaerobe最新文献

Bovine digital dermatitis (BDD) is an infectious skin disease of the hoof characterized by painful ulcerations that cause lameness in dairy cattle. Cell-free supernatants (CFS) of Falsiporphyromonas endometrii predominantly isolated from BDD lesions had the highest growth-stimulating effect on Treponema phagedenis among BDD-associated bacteria. Butyric acid was detected at a concentration of 45.4 mM in CFS of F. endometrii, and the growth of T. phagedenis was significantly promoted by butyric acid supplementation.

Objective

Methods

Results

Conclusions

This study reports a botulism outbreak on a pig farm. Clostridium botulinum type C was detected using PCR. The gene encoding the toxin corresponds to a novel type C neurotoxin recently described in a human botulism outbreak, raising the question of its prevalence in pigs and the related risks to humans.

Objectives

Syntrophy has been documented between pectinophiles and methanol-utilizing bacteria, along with instances of cross-feeding between pectinophiles and methanogens. However, studies on the ecology of pectinophiles in anaerobic digestion (AD) are lacking. Therefore, in this study, we aimed to elucidate the ecology of pectinophiles by isolating novel pectinophile forms and conducting a comprehensive analysis of their physiology and ecology.

Methods

Complex microbial communities from AD systems were enriched in a pectin-containing medium; subsequently, specific strains were isolated using a pectinophile isolation method. The carbon source assimilation and growth ability of the isolates, along with their symbiotic relationships, were evaluated using batch tests.

Results

Strain LPYR103-Pre exhibited 16S rRNA gene sequence similarity and average nucleotide identity values of 94.3 % and 77.9 %, respectively, compared to its closest related species, Segatella cerevisiae. Strain LPYR103-Pre demonstrated attenuated growth in the presence of eight common sugars but exhibited remarkably high growth in the presence of pectin, d-galacturonate, and d-glucuronate, with succinate being identified as a primary metabolite. Accumulation of succinate inhibited the growth of strain LPYR103-Pre. However, this growth impediment was alleviated by Dialister hominis LPYG114-Dih, whose growth required succinate.

Conclusions

Our results elucidate the specific carbon source requirements of the Segatella-like strain LPYR103-Pre and succinate-mediated symbiosis involving D. hominis. These findings provide new insights into the degradation of pectin and its degradation products during AD, contributing to the identification of unknown pectinophiles.

Background

Colorectal cancer (CRC) is a significant global health concern, and understanding the role of specific bacterial infections in its development and progression is of increasing interest. This cross-sectional study investigated the associations between Bacteroides fragilis (B. fragilis) and Fusobacterium nucleatum (F. nucleatum) infections and Vietnamese CRC patients.

Methods

192 patients with either polyps or CRC at varying stages were recruited from May 2017 to December 2020. Real-time PCR assessed infection rates and bacterial loads in CRC tissues.

Results

B. fragilis infection was notably higher in CRC tissues (51.6 %) than polyps (9.4 %), with a fivefold higher relative load. Positive associations were found in stages II and III, indicating a fivefold increase in CRC progression risk. F. nucleatum infection rates were significantly higher in CRC tissues (55.2 %) than in polyps (10.5 %). In stage II, the infection rate exceeded that in adjacent tissues. The relative load of F. nucleatum was higher in stage III than in stages I and II. Positive F. nucleatum patients had a 3.2 times higher risk of CRC progression.

Conclusion

These findings suggest associations between loading of F. nucleatum or/and B. fragilis with the advanced stages of CRC.

Objectives

The genus Faecalibacterium is one of the most important butyrate producers in the human intestinal tract and has been widely linked to health. Recently, several different species have been described, but still more phylogroups have been identified, suggesting that additional species may exist. Four strains HTF-F^T, HTF-128, HTF-75H and HTF-76H, representing two different phylogenetic clusters, are evaluated in this study.

Methods

Phylogenomic analysis was performed using whole-genome sequences and 16S rRNA gene sequences. Chemotaxonomic analysis was done based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Physiological and phenotypical characteristics of these strains were also determined. All characteristics of these strains were compared with other validly published species within the genus Faecalibacterium.

Results

On a genomic level, the strains HTF-F^T and HTF-128 shared an average nucleotide identity (ANI) of <95.0 % and digital DNA-DNA hybridization (dDDH) of <70.0 with other Faecalibacterium species, while between HTF-F^T and HTF-128 the ANI-value was 97.18 % and the dDDH was 76.8 %. HTF-75H and HTF-76H had an ANI and dDDH value of 100 % (99.96 %) and 100 % (99.99 %) respectively. Both HTF-75H and HTF-76H were closely related to Faecalibacterium taiwanense HLW78^T. 16S rRNA gene and chemotaxonomic analysis were in accordance with the genomic data, confirming that HTF-F^T and HTF-128 represent a novel Faecalibacterium species and HTF-75H and HTF-76H belong to F. taiwanense.

Conclusions

Faecalibacterium strains HTF-F^T (=DSM 117771^T = NCIMB 15531^T) and HTF-128 represent a novel species. The name Faecalibacterium wellingii with HTF-F^T as type strain is proposed. Two novel isolates HTF-75H (=DSM 17770 = NCIMB 15530) and HTF-76H are described in this study and belong to the recently described Faecalibacterium taiwanense.

Clostridioides difficile infection (CDI) is an important cause of morbidity and mortality worldwide. Data from public health surveillance systems are important for estimating country-level CDI burden. CDI surveillance can be population-based or hospital-based. Population-based surveillance results in overall estimates of CDI incidence (cases per 100,000 population-per-year), and hospital-based surveillance results in estimates of hospital-based CDI incidence (cases per 10,000 patient-days) or CDI admission rates (cases per 1,000 admissions). We sought to better understand temporal trends in CDI incidence reported in publicly available surveillance data worldwide and describe varying surveillance methods. We identified 13 countries in Europe, North America, and Oceania with publicly available population-based and/or hospital-based CDI surveillance data in online reports and/or dashboards. Additional countries in Europe, in particular, also conduct hospital-based CDI surveillance. Inconsistent CDI case definitions and surveillance approaches between countries limit the interpretability of multi-country comparisons. Nonetheless, publicly available CDI surveillance data enabled us to compare CDI incidence among countries with population-based and/or hospital-based surveillance systems and to describe trends in CDI incidence within countries over time. The highest CDI incidence is in the United States. While there have been recent declines in CDI incidence in all countries, the CDI burden remains high, and the need persists for CDI prevention strategies in communities and healthcare settings.

Veillonella parvula is a non-motile Gram-negative coccus that forms part of the normal microbiota in several body sites and which has been rarely isolated as cause of infections in human population, particularly in bacteremias. Here we give the overview of characteristics of genus Veillonella and the summary of its role in infections, particularly in bacteremia. We additionally report two patients with bacteremia due to V. parvula. Two sets of blood cultures of each patient yielded a pure culture of an anaerobic microorganism identified as V. parvula by MALDI-TOF MS, and confirmed by 16S rRNA gene sequencing. The two patients were male and one of them had risk factors for anaerobic bacteremia. The isolates were susceptible to most antibiotics and the outcome was successful in both patients. Bacteremia due to V. parvula is still rare. MALDI-TOF MS appear to be an excellent tool for the correct identification of these species.

Objectives

This lab-scale study aimed to investigate the effect of total ammonia nitrogen (TAN) stress on the methanogenic activity and the taxonomic and functional profiles of the microbial community of anaerobic sludge (AS) from a full-scale bioreactor.

Methods

The AS was subjected to a stepwise increase in TAN every 14 days at concentrations of 1, 2, 2.5, 3, 3.5, and 4 g TAN/L (Acclimated-AS or AAS). This acclimation stage was followed by an ammonia stress stage (4 g/L). A blank-AS (BAS) was maintained without TAN during the acclimation stage. In the second stress stage (ST), the BAS was divided into two new treatments: a control (BAS') and one that received a shock load of TAN of 4 g/L (SBAS'). Methane production was measured, and a metagenomic analysis was conducted to describe the microbial community.

Results

A decrease in the relative abundance of Methanothrix soehngenii of 16 % was related to a decrease of 23 % in the methanogenic capacity of AAS when comparing with the final stage of BAS. However, recovery was observed at 3.5 g TAN/L, and a shift to methylotrophic metabolism occurred, indicated by a 4-fold increase in abundance of Methanosarcina mazei. The functional analysis of sludge metagenomes indicated that no statistical differences (p > 0.05, RM ANOVA) were found in the relative abundance of methanogenic genes that initiate acetoclastic and hydrogenotrophic pathways (acetyl-CoA synthetase, ACSS; acetate kinase, ackA; phosphate acetyltransferase, pta; and formylmethanofuran dehydrogenase subunit A, fwdA) into the BAS and AAS during the acclimation phase. The same was observed between groups of genes associated with methanogenesis from methylated compounds. In contrast, statistical differences (p < 0.05, one-way ANOVA) in the relative abundance of these genes were recorded during ST. The functional profiles of the genes involved in acetoclastic, hydrogenotrophic, and methylotrophic methanogenic pathways were brought to light for acclimatation and stress experimental stages.

Conclusions

TAN inhibited methanogenic activity and acetoclastic metabolism. The gradual acclimatization to TAN leads to metabolic and taxonomic changes that allow for the subsequent recovery of methanogenic functionality. The study highlights the importance of adequate management of anaerobic bioprocesses with high nitrogen loads to maintain the methanogenic functionality of the microbial community.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) can misidentify Cutibacterium namnetense and Cutibacterium modestum as Cutibacterium acnes. We now describe how such MALDI-TOF MS misidentification explains previous reports of C. acnes isolates that could not be characterised using a multiplex PCR phylotyping assay.