Search

Metabolic disorders present a significant public health challenge globally. The intricate relationship between the gut microbiome, particularly Bacteroides spp. (BAC), and obesity, including their specific metabolic functions, remains partly unresolved. This review consolidates current research on BAC's role in obesity and lipid metabolism, with three objectives: (1) To summarize the gut microbiota's impact on obesity; (2) To assess BAC's efficacy in obesity intervention; (3) To explore BAC's mechanisms in obesity and lipid metabolism management. This review critically examines the role of BAC in obesity, integrating findings from clinical and preclinical studies. We highlight the changes in BAC diversity and concentration following successful obesity treatment and discuss the notable differences in BAC characteristics among individuals with varying obesity levels. Furthermore, we review recent preclinical studies demonstrating the potential of BAC in ameliorating obesity and related inflammatory conditions, providing detailed insights into the methodologies of these in vivo experiments. Additionally, certain BAC-derived metabolites have been shown to be involved in the regulation of host lipid metabolism-related pathways. The enhanced TNF production by dendritic cells following BAC administration, in response to LPS, also positions BAC as a potential adjunctive therapy in obesity management. [ABSTRACT FROM AUTHOR]

Bacteroides spp. are the most common anaerobic bacteria isolated from the human gastrointestinal tract. Several resistant genes are present in Bacteroides spp. However, most studies have focused on the prevalence of the c fi A gene in Bacteroides fragilis alone. We assessed the susceptibility to antimicrobial agents and the prevalence of cepA , cfiA , cfxA , ermF , nim , and tetQ genes in Bacteroides strains isolated from clinical specimens in our hospital. We isolated 86 B. fragilis and 58 non- fragilis Bacteroides strains from human clinical specimens collected from January 2011 to November 2021. Resistance against piperacillin (PIPC), cefotaxime (CTX), cefepime (CFPM), meropenem (MEPM), clindamycin, and minocycline was determined. The resistant rates of penicillins and cephalosporins in non- fragilis isolates were significantly higher than those in B. fragilis isolates. In B. fragilis isolates, the resistant rates of PIPC, CTX, and CFPM in cfxA- positive isolates were significantly higher than those in cfxA- negative isolates (71% vs. 16%, 77% vs. 19%, and 77% vs. 30%, respectively). Thirteen B. fragilis isolates harbored the cfiA gene, two of which were resistant to MEPM. Six of the 13 cfiA -positive B. fragilis isolates were heterogeneously resistant to MEPM. It is important to evaluate the use of MEPM as empirical therapy for Bacteroides spp. infections, considering the emergence of carbapenem resistance during treatment, existence of MEPM-resistant strains, and heterogeneous resistance. [ABSTRACT FROM AUTHOR]

Bacteroides spp. are prominent members of the human gut microbiota that play critical roles in the metabolism of complex carbohydrates from the daily diet. Hyaluronic acid (HA) is a multifunctional polysaccharide which has been extensively used in the food and biomedical industry. However, how HA is degraded and fermented by Bacteroides spp. has not been fully characterized. Here, we comprehensively investigated the detailed degradation profiles and fermentation characteristics of four different HAs with discrete molecular weight (Mw) by fourteen distinctive Bacteroides spp. from the human gut microbiota. Our results indicated that high-Mw HAs were more degradable and fermentable than low-Mw HAs. Interestingly, B. salyersiae showed the best degrading capability for both high-Mw and low-Mw HAs, making it a keystone species for HA degradation among Bacteroides spp.. Specifically, HA degradation by B. salyersiae produced significant amounts of unsaturated tetrasaccharide (udp4). Co-culture experiments indicated that the produced udp4 could be further fermented and utilized by non-proficient HA-degraders, suggesting a possible cross-feeding interaction in the utilization of HA within the Bacteroides spp.. Altogether, our study provides novel insights into the metabolism of HA by the human gut microbiota, which has considerable implications for the development of new HA-based nutraceuticals and medicines. [ABSTRACT FROM AUTHOR]

Purpose: The intestine has substantial role in cholesterol homeostasis due to the presence of various cholesterol transporters and gut microbiota. Bacteroides spp. are important members of gut microbiota that employ outer membrane vesicles (OMVs) to interact with host. In this regard, we evaluated the effect of Bacteroides fragilis, Bacteroides thetaiotaomicron and related OMVs on the gene expression of important cholesterol transporters, Niemann-Pick C1-Like 1 (NPC1L1), ATP-binding cassette (ABCA1), and liver X receptors (LXRs) in Caco-2 cells. Methods: OMVs were isolated from overnight brain heart infusion (BHI) broth of bacterial standard strains using deoxycholate and assessed by Scanning electron microscopy (SEM). The relative change in genes expression was assessed by Quantitative reverse transcription PCR (RT-qPCR) based on SYBR Green and 2-∆∆ct method in Caco-2 cells that were treated with bacteria and OMVs. Data were statistically analyzed with GraphPad Prism software. Finally, pathway enrichment based on the studied genes was performed using Cytoscape plugin ClueGO. Results: B. fragilis (P value = 0.002) and B. thetaiotaomicron (P value = 0.001) significantly reduced NPC1L1 gene expression in Caco-2 cells. Interestingly, NPC1L1 transcripts were significantly increased by both OMVs(P value = 0.04) (P value = 0.01). Also, LXRβ was significantly down regulated by B. thetaiotaomicron (P value = 0.02). ClueGO analysis on the studied genes demonstrated several functional groups which involve in lipid and cholesterol metabolism. Conclusion: The opposite effect of B. fragilis, B. thetaiotaomicron and related OMVs on the NPC1L1 gene expression was observed in Caco-2 cells. Interestingly, these effects partially were in line with the alternation of LXRs expression. However, based on pathway enrichment analysis, further molecular investigations are required to elaborate in details the specific association between Bacteroides spp. and OMVs with regulation of cholesterol signaling pathways including cholesterol transport, lipid storage, lipid homeostasis and cholesterol homeostasis. [ABSTRACT FROM AUTHOR]

Fecal pollution monitoring using fecal indicator bacteria has many limitations. Alternatively, using 16S rRNA gene Bacteroides-based polymerase chain reaction (PCR) showed promise because Bacteroides spp. are a major part of the gut microbiota. In the Philippines, duck backyard farming waste management is unmonitored. Hence, the objective of this study was to isolate Bacteroides DNA from duck feces and to establish genetic relatedness that can be used to develop new microbial source tracking markers. Fifty (50) duck fecal samples were collected. Of the 50, 20 were subjected to total DNA extraction and the remaining 30 were used for the isolation of Bacteroides. A total of 32 Bacteroides were isolated that included 6 B. nordii and 26 B. ovatus. A phylogenetic tree showing the host sources of Bacteroides generated five clusters. Four clusters came from this study, while the fifth cluster was composed of sequences from a study in Japan. This shows an intraspecies difference between Bacteroides species in the Philippines and Japan. This difference is a result of variations in the gut microbiome such as host species, diet, and geography. Results of this study will expand the present sequence database of Bacteroides from ducks that can be used in identifying sources of fecal pollution in the environment. [ABSTRACT FROM AUTHOR]

The gut microbiota plays a significant role in influencing human immunity, metabolism, development, and behavior by producing a wide range of metabolites. While there is accumulating data on several microbiota-derived small molecules that contribute to host health and disease, our knowledge regarding the molecular mechanisms underlying metabolite-mediated microbe-host interactions remains limited. This is primarily due to the lack of efficient genetic tools for most commensal bacteria, especially those belonging to the dominant phyla Bacteroides spp. and Clostridium spp., which hinders the application of synthetic biology to these gut commensal bacteria. In this review, we provide an overview of recent advances in synthetic biology tools developed for the two dominant genera, as well as their applications in deciphering the mechanisms of microbe-host interactions mediated by microbiota-derived small molecules. We also discuss the potential biomedical applications of engineering commensal bacteria using these toolboxes. Finally, we share our perspective on the future development of synthetic biology tools for a better understanding of small molecule-mediated microbe-host interactions and their engineering for biomedical purposes. [ABSTRACT FROM AUTHOR]

Macropod progressive periodontal disease (MPPD) is a necrotizing, polymicrobial, inflammatory disease commonly diagnosed in captive macropods. MPPD is characterized by gingivitis associated with dental plaque formation, which progresses to periodontitis and then to osteomyelitis of the mandible or maxilla. However, the underlying microbial causes of this disease remain poorly understood. In this study, we collected 27 oral plaque samples and associated clinical records from 22 captive Macropodidae and Potoroidae individuals that were undergoing clinical examination at Adelaide and Monarto Zoos in South Australia (15 healthy, 7 gingivitis and 5 periodontitis-osteomyelitis samples). The V3-V4 region of the 16S ribosomal RNA gene was sequenced using an Illumina Miseq to explore links between MPPD and oral bacteria in these animals. Compositional differences were detected between the microbiota of periodontitis-osteomyelitis cases compared to healthy samples (p-value with Bonferroni correction < 0.01), as well as gingivitis cases compared to healthy samples (p-value with Bonferroni correction < 0.05) using Permutational Multivariate Analysis of Variance (PERMANOVA). An overabundance of Porphyromonas, Fusobacterium, and Bacteroides taxa was also identified in animals with MPPD compared to healthy individuals using linear discriminant analysis effect size (LEfSe; p = < 0.05). An increased abundance of Desulfomicrobium also was detected in MPPD samples (LEfSe; p < 0.05), which could potentially reflect differences in disease progression. This is the first microbiota analysis of MPPD in captive macropods, and these results support a polymicrobial pathogenesis of MPPD, suggesting that the microbial interactions underpinning MPPD may be more complex than previously documented. [ABSTRACT FROM AUTHOR]

Antimicrobial susceptibilities of 4973 Bacteroides spp. isolates recovered from various sources of patients from 12 countries (99.6% from European countries) in the Antimicrobial Testing Leadership and Surveillance (ATLAS) programme, 2007–2020, were investigated. The minimum inhibitory concentrations (MICs) of the isolates with six commonly used agents were determined using the agar dilution method. Among the isolates, 10 Bacteroides spp. were included: B. fragilis (n =3180, 64.0%) was encountered most frequently, followed by B. thetaiotaomicron (n =675) and B. ovatus (n =409). During the 14 years, the proportion of B. fragilis declined, but the proportion of non- fragilis Bacteroides spp. increased. More than 90% of the isolates tested were susceptible to piperacillin-tazobactam, meropenem and tigecycline. Significantly lower susceptibility rates to cefoxitin (P <0.001), clindamycin (P <0.001), piperacillin/tazobactam (P <0.001) and tigecycline (P =0.006) were observed among non- fragilis Bacteroides spp. isolates than among B. fragilis isolates. Moreover, the susceptibility rates to clindamycin (P =0.003) and tigecycline (P =0.044) decreased significantly among non- fragilis Bacteroides spp. over time. Clindamycin susceptibility rates >80% were found in Greece (100%), Sweden (86.3%) and the UK (80.7%), and the lowest susceptibility rates were found in the USA (42.9%) and Japan (53.9%). In conclusion, the susceptibility of Bacteroides spp. to commonly used antibiotics varied geographically. Empirical antibiotic therapy for suspected anaerobic infections with clindamycin and cefoxitin should be avoided due to high resistance rates. Piperacillin-tazobactam, meropenem, metronidazole and tigecycline could be considered favourable options for the treatment of infections caused by Bacteroides spp. [ABSTRACT FROM AUTHOR]

Abstract Probiotics play important roles on sustaining or reconstructing the homeostasis of intestinal microbiota, which is one of the key factors in alleviating diseases and maintaining the healthy condition of the host. Preclinical trials indicate that Bacteroides genus is widely considered as source of novel beneficial candidates for attenuating inflammation by regulating lymphocytes and cytokine expression, controlling metabolism and preventing cancer. Furthermore, the first case of authorization of Bacteroides xylanisolvens in food by the European Commission opens the gate for further investigation and application of this promising community. With this paper, we summarized current investigations of discovering beneficial Bacteroides strains, exploring their interaction mechanisms with the host, and evaluating the potential safety risks during commercialization. Graphical abstract Unlabelled Image Highlights • Bacteroides spp. interact with the host by modifying immune cells and regulating metabolites. • Bacteroides spp. can improve different intestinal disorders, as well as cardiovascular disease, behavior disorders and cancer. • Bacteroides strains have been started in authorization in food processing by the European Commission after safety evaluation. • Bacteroides genus is widely considered as source of next-generation probiotics. [ABSTRACT FROM AUTHOR]

A lysimeter-based field study was done to monitor the transfer of culturable Escherichia coli , general (ALLBAC), human (Hf183) and swine (PIG-BAC-1) specific 16S rRNA Bacteroides spp. markers, nutrients and metals through soils and leachate over time following land application of a CP1/Class A as well as two CP2/Class B municipal biosolids (MBs). Hf183 markers were detected up to six days following application in soils receiving dewatered and liquid MBs, but not in leachate, suggesting their use in source tracking is better suited for recent pollution events. The CP2/Class B biosolids and swine manure contributed the highest microbial load with E. coli loads (between 2.5 and 3.7 log CFU (100 mL) −1 ) being greater than North American concentration recommendations for safe recreational water. ALLBAC persisted in soils and leachate receiving all treatments and was detected prior to amendment application demonstrating its unsuitability for identifying the presence of fecal pollution. A significant increase in NO 3 –N (for Lystek and dewatered MBs) and total-P (for dewatered and liquid MBs) in leachate was observed in plots receiving the CP1/Class A and CP2/Class B type MBs which exceeded North American guidelines, suggesting impact to surface water. Metal (As, Cd, Cr, Co, Cu, Pb, Mo, Ni, Se, Zn and Hg) transfer was negligible in soil and leachate samples receiving all treatments. This study is one of the first to examine the fate of E. coli and Bacteroides spp. markers in situ following the land application of MBs where surface runoff does not apply. [ABSTRACT FROM AUTHOR]

Achyranthes bidentata (A. bidentata) is a famous traditional Chinese medicine (TGM) for treatment osteoporosis. Polysaccharides, a major factor for shaping the gut microbiota, are the primary ingredients of A. bidentata. However, bioactivity of A. bidentata polysaccharide on human gut microbiota (HGM) remains unknown. Here, a homogeneous pectic polysaccharide A23–1 with average molecular weight of 93.085 kDa was extracted and purified from A. bidentata. And A23–1 was compsed of rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose in a molar ratio of 7.26: 0.76: 5.12: 2.54: 23.51: 60.81. GC–MS, partial acid hydrolysis and NMR results indicated the backbone of A23–1 was composed of 1, 2, 4-Rha p and 1, 4-Gla p A, while the branches were composed of galactose, arabinose, glucose and glucuronic acid. Further, A23–1 was found to be degraded into monosaccharides and fragments. Taking Bacteroides thetaiotaomicron (BT) as a model, we suggested three polysaccharide utilization loci (PULs) might be involved in the A23–1 degradation. Degraded products generated by BO might not support the growth of probiotics. Besides, acetate and propionate as the main end products were generated by Bacteroides spp. and probiotics utilizing A23–1. These findings suggested A23–1 was possible one of food sources of human gut Bacteroides spp. • The structure of a pectic polysaccharide A23–1 from A. bidentata was elucidated. • A23–1 could be degraded by human gut Bacteroides spp. • The degradation process might be dictated by three PULs. • There was possible no cross feeding between Bacteroides ovatus and probiotics. • Bacteroides spp. produced SCFAs by utilizing A23–1. [ABSTRACT FROM AUTHOR]

Bacteroides spp. are members of the human gut microbiota that confer myriad benefits on their hosts. Among them is the provision of energy from otherwise indigestible polysaccharides comprising part of the host diet, lining the intestinal mucosal layer, and decorating the surface of other microbes. Bacteroides spp. devote ∼20% of their genomes to the transport and breakdown of a wide variety of polysaccharides, and to the regulation of these processes. Bacteroides spp. rely on different families of transcriptional regulators to ensure that carbohydrate utilization genes are expressed under specific conditions. The regulators and mechanisms controlling carbohydrate utilization are often unique to these gut-dwelling bacteria, and do not conform to those of model organisms. [ABSTRACT FROM AUTHOR]

Monitoring of sanitary quality or faecal pollution in water is currently based on quantifying some bacterial indicators such as Escherichia coli and faecal enterococci. Using a multiplex real-time PCR assay for faecal enterococci and Bacteroides spp., the detection of faecal contamination in non-treated water can be done in a few hours, reducing the analysis time to 2 h. The conventional method based on cultures was compared with a multiplex assay procedure for Bacteroides spp. and faecal enterococci with an internal inhibition control. Out of 74 water samples from different sources analyzed, using both procedures, 54 were true positives and 6 true negatives, 12 samples were real-time PCR positive and culture-negative whereas 2 were real-time PCR negative and culture-positive. In conclusion, 89.2% of the samples were found to be positive with real-time PCR and 75.7% with plate cultures. Detection levels were much higher when using the multiplex real-time PCR assay, based on the higher number of positive samples in comparison with conventional microbiology. The feasibility of multiple reactions in the monitoring of faecal contamination has been demonstrated along with fast quantification of the faecal load. Such procedure can be performed in less than 3 h. This work extends the use of multiplex real-time PCR for environmental analysis, demonstrating the feasibility of these procedures in monitoring faecal pollution of water samples. [ABSTRACT FROM AUTHOR]

Identification of sources of fecal contaminants is needed to (i) determine the health risk associated with recreational water use and (ii) implement appropriate management practices to mitigate this risk and protect the environment. This study evaluated human-associated Bacteroides spp. (HF183TaqMan) and human polyomavirus (HPyV) markers for host sensitivity and specificity using human and animal fecal samples collected in Hawaii. The decay rates of those markers and indicator bacteria were identified in marine and freshwater microcosms exposed and not exposed to sunlight, followed by field testing of the usability of the molecular markers. Both markers were strongly associated with sewage, although the cross-reactivity of the HF183TaqMan (also present in 82% of canine [n=11], 30% of mongoose [n=10], and 10% of feline [n=10] samples) needs to be considered. Concentrations of HF183TaqMan in human fecal samples exceeded those in cross-reactive animals at least 1,000-fold. In the absence of sunlight, the decay rates of both markers were comparable to the die-off rates of enterococci in experimental freshwater and marine water microcosms. However, in sunlight, the decay rates of both markers were significantly lower than the decay rate of enterococci. While both markers have their individual limitations in terms of sensitivity and specificity, these limitations can be mitigated by using both markers simultaneously; ergo, this study supports the concurrent use of HF183TaqMan and HPyV markers for the detection of sewage contamination in coastal and inland waters in Hawaii. [ABSTRACT FROM AUTHOR]

Human gut microbiota species which are next-generation probiotics (NGPs) candidates are of high interest as they have shown the potential to treat intestinal inflammation and other diseases. Unfortunately, these species are often not robust enough for large-scale cultivation, especially in maintaining diversity in co-culture production. In this study, we describe interactions between human gut microbiota species in the cultivation process with unique substrates. We also demonstrated that it is possible to change the species ratio in co-culture by changing the ratio of carbon sources. We screened 25 different bacterial species based on their metabolic capabilities. After evaluating unique substrate possibilities, we chose Anaerostipes caccae (A. caccae), Bacteroides thetaiotaomicron (B. thetaiotaomicron), and Bacteroides vulgatus (B. vulgatus) as subjects for further study. D-sorbitol, D-xylose, and D-galacturonic acid were selected as substrates for A. caccae , B. thetaiotaomicron , and B. vulgatus respectively. All three species were cultivated as both monocultures and in co-cultures in serial batch fermentations in an isothermal microcalorimeter. Positive interactions were detected between the species in both co-cultures (A. caccae + B. thetaiotaomicron ; A. caccae + B. vulgatus) resulting in higher heat production compared to the sum of the monocultures. The same positive cross-feeding interactions took place in larger-scale cultivation experiments. We confirmed acetate and lactate cross-feeding between A. caccae and B. thetaiotaomicron with flux balance analysis (FBA). Changing the ratio of the selected carbon sources in the medium changed the species ratio accordingly. Such robustness is the basis for developing more efficient industrial co-culture processes including the production of NGPs. • The growth of 25 bacterial species was evaluated in chemically defined medium. • A. caccae , B. thetaiotaomicron , and B. vulgatus were chosen as model organisms. • Stable co-culture was achieved throughout three consecutive batches. • Trophic interactions of A. caccae and Bacteroides spp. boost species' growth rates. • Unique substrates help to control biomass concentrations in co-culture production. [ABSTRACT FROM AUTHOR]

An experimental group of one-day-old chicken from a commercial hatchery was given a defined mixture of 7 gut anaerobes. The next day the chicks were inoculated by an APEC strain O78:H4-ST117 resistant to ciprofloxacin, alongside with the control group and monitored for 4 wk after the inoculation for the presence of the colonizing strains and ciprofloxacin-resistant E. coli. Significant reduction of colonization rates in the first 2 wk was recorded in the experimental group for the numbers of ciprofloxacin-resistant E. coli. The results show that colonization of chicken by defined anaerobic mixtures may provide a decisive protection during the critical period of the chicken intestinal microflora development. [ABSTRACT FROM AUTHOR]

Glycoside hydrolase family 99 (GH99) was created to categorize sequence-related glycosidases possessing endo-α-mannosidase activity: the cleavage of mannosidic linkages within eukaryotic N-glycan precursors (Glc1-3Man9GlcNAc2), releasing mono-, di- and triglucosylated-mannose (Glc1-3-1,3-Man). GH99 family members have recently been implicated in the ability of Bacteroides spp., present within the gut microbiota, to metabolize fungal cell wall α-mannans, releasing α-1,3-mannobiose by hydrolysing αMan-1,3-αMan→1,2-αMan-1,2-αMan sequences within branches off the main α-1,6-mannan backbone. We report the development of a series of substrates and inhibitors, which we use to kinetically and structurally characterise this novel endo-α-1,2-mannanase activity of bacterial GH99 enzymes from Bacteroides thetaiotaomicron and xylanisolvens. These data reveal an approximate 5 kJ mol−1 preference for mannose-configured substrates in the −2 subsite (relative to glucose), which inspired the development of a new inhibitor, α-mannopyranosyl-1,3-isofagomine (ManIFG), the most potent (bacterial) GH99 inhibitor reported to date. X-ray structures of ManIFG or a substrate in complex with wild-type or inactive mutants, respectively, of B. xylanisolvens GH99 reveal the structural basis for binding to D-mannose- rather than D-glucose-configured substrates. [ABSTRACT FROM AUTHOR]

Abstract: Concentrations of fecal indicator bacteria (FIB; e.g. Escherichia coli, and Enterococcus sp.) can only be used in limited ways for determining the source of fecal contamination in recreational waters because they cannot distinguish human from non-human fecal contamination. Several Bacteroides spp. have been suggested as potential alternative indicators. We have developed a rapid, culture-independent method for quantifying fecal Bacteroides spp. using quantitative PCR (QPCR) targeting the 16S rRNA gene. The assay specifically targets and quantifies the most common human Bacteroides spp. The details of the method are presented, including analyses of a wide range of fecal samples from different organisms. Specificity and performance of the QPCR assay were also tested via a laboratory experiment where human sewage and gull guano were inoculated into a range of environmental water samples. Concentrations of fecal Bacteroides spp., total Enterococcus sp., Enterococcus faecium, Enterococcus faecalis, and Enterococcus casseliflavus were measured using QPCR, and total Enterococcus sp. and E. coli were quantified by membrane filtration (MF). Samples spiked with gull guano were highly concentrated with total Enterococcus sp., E. coli, E. faecalis, and E. casseliflavus, demonstrating that these indicators are prominent in animal feces. On the other hand, fecal Bacteroides spp. concentrations were high in samples containing sewage and were relatively low in samples spiked with gull guano. Sensitivity and specificity results suggest that the rapid fecal Bacteroides spp. QPCR assay may be a useful tool to effectively predict the presence and concentration of human-specific fecal pollution. [Copyright &y& Elsevier]

A molecular method, termed hierarchical oligonucleotide primer extension (HOPE), was used to determine the relative abundances of predominant Bacteroides spp. present in fecal microbiota and wastewaters. For this analysis, genomic DNA in feces of healthy human adults, bovines, and swine and in wastewaters was extracted and total bacterial 16S rRNA genes were PCR amplified and used as the DNA templates for HOPE. Nineteen oligonucleotide primers were designed to detect 14 Bacteroides spp. at different hierarchical levels (domain, order, cluster, and species) and were arranged into and used in six multiplex HOPE reaction mixtures. Results showed that species like B. vulgatus, B. thetaiotaomicron, B. caccae, B. uniformis, B. fragilis, B. eggerthii, and B. massiliensis could be individually detected in human feces at abundances corresponding to as little as 0.1% of PCR-amplified 16S rRNA genes. Minor species like B. pyogenes, B. salyersiae, and B. nordii were detected only collectively using a primer that targeted the B. fragilis subgroup (corresponding to ∼0.2% of PCR-amplified 16S rRNA genes). Furthermore, Bac303-related targets (i.e., most Bacteroidales) were observed to account for 28 to 44% of PCR-amplified 16S rRNA genes from human fecal microbiota, and their abundances were higher than those detected in the bovine and swine fecal microbiota and in wastewaters by factors of five and two, respectively. These results were comparable to those obtained by quantitative PCR and to those reported previously from studies using whole-cell fluorescence hybridization and 16S rRNA clone library methods, supporting the conclusion that HOPE can be a sensitive, specific, and rapid method to determine the relative abundances of Bacteroides spp. predominant in fecal samples. [ABSTRACT FROM AUTHOR]

Partial rpoB sequences (317 bp) of 11 species of Bacteroides, two Porphyromonas spp. and two Prevotella spp. were compared to delineate the genetic relationships among Bacteroides and closely related anaerobic species. The high level of inter-species sequence dissimilarities (7.6–20.8%) allowed the various Bacteroides spp. to be distinguished. The position of the Bacteroides distasonis and Bacteriodes merdae cluster in the rpoB tree was different from the position in the 16S rRNA gene tree. Based on rpoB sequence similarity and clustering in the rpoB tree, it was possible to correctly re-identify 80 clinical isolates of Bacteroides. In addition to two subgroups, cfiA-negative (division I) and cfiA-positive (division II), of Bacteroides fragilis isolates, two distinct subgroups were also found among Bacteroides ovatus and Bacteroides thetaiotaomicron isolates. Bacteroides genus-specific rpoB PCR and B. fragilis species-specific rpoB PCR allowed Bacteroides spp. to be differentiated from Porphyromonas and Prevotella spp., and also allowed B. fragilis to be differentiated from other non- fragilis Bacteroides spp. included in the present study. [ABSTRACT FROM AUTHOR]

Members of the Bacteroides spp. are the anaerobic pathogens most commonly isolated from human clinical material. Metronidazole has been the drug of choice for the prevention and treatment of Bacteroides and other such anaerobic infections for nearly 40 years. Although the emergence of metronidazole-resistance in Bacteroides spp. was reported recently, the published rate remains low, at <5%. Isolates of Bacteroides spp. originating from different wards at the University Hospital of Szeged in Hungary were investigated for metronidazole resistance genes by PCR and characterized by other molecular methods. We report here the first strains of Bacteroides spp. with elevated MICs to metronidazole from Hungary. Of 167 isolates, four had metronidazole MICs >2 μg/mL, and two were positive fornim genes with metronidazole MICs of 4 and 12 μg/mL. The nim genes were determined to be nim A and nim B, and proved to be activated by upstream copies of the IS1186 element. The nim A gene was localized in a pIP417-like plasmid, and the nim B gene on the chromosome. [Copyright &y& Elsevier]

Objectives To identify β-lactamase genes in gut commensal Bacteroides species and to assess the impact of these enzymes, when carried by outer membrane vesicles (OMVs), in protecting enteric pathogens and commensals. Methods A deletion mutant of the putative class A β-lactamase gene (locus tag BT_4507) found in the genome of the human commensal Bacteroides thetaiotaomicron was constructed and a phenotypic analysis performed. A phylogenetic tree was built from an alignment of nine Bacteroides cephalosporinase protein sequences, using the maximum likelihood method. The rate of cefotaxime degradation after incubation with OMVs produced by different Bacteroides species was quantified using a disc susceptibility test. The resistance of Salmonella Typhimurium and Bifidobacterium breve to cefotaxime in liquid culture in the presence of B. thetaiotaomicron OMVs was evaluated by measuring bacterial growth. Results The B. thetaiotaomicron BT_4507 gene encodes a β-lactamase related to the CepA cephalosporinase of Bacteroides fragilis. OMVs produced by B. thetaiotaomicron and several other Bacteroides species, except Bacteroides ovatus, carried surface-associated β-lactamases that could degrade cefotaxime. β-Lactamase-harbouring OMVs from B. thetaiotaomicron protected Salmonella Typhimurium and B. breve from an otherwise lethal dose of cefotaxime. Conclusions The production of membrane vesicles carrying surface-associated β-lactamases by Bacteroides species, which constitute a major part of the human colonic microbiota, may protect commensal bacteria and enteric pathogens, such as Salmonella Typhimurium, against β-lactam antibiotics. [ABSTRACT FROM PUBLISHER]

Describes the cellular and molecular biology of bacterial conjugation for the F plasmid of Escherichia coli, emphasizing the necessity of the pBF4 gene in the conjugal transfer in bacteroides spp. Identification of pBF4 genes governing conjugation; Assessment of molecular and cellular knowledge of conjugal transfer in bacteroides spp; Details on bacterial conjugation.

Studies the ability of NBU1, a mobilizable site-specific integrated element from Bacteroides spp., to integrate nonspecifically in Escherichia coli. Random integration of NBU1 in E. coli; Lower insertion frequency; Identification of NBU1 attachment site.

Bacteroides are Gram-negative anaerobes indigenous to the intestinal tract of humans, and they are important opportunistic pathogens. Mobile genetic elements, such as conjugative transposons (CTns), have contributed to an increase in antibiotic resistance in these organisms. CTns are self-transmissible elements that belong to the superfamily of integrative and conjugative elements (ICEs). CTn341 is 52 kb; it encodes tetracycline resistance and its transfer is induced by tetracycline. The mobilization region of CTn341 was shown to be comprised of a three-gene operon, mobABC, and the transfer origin, oriT. The three genes code for a nicking accessory protein, a relaxase, and a VirD4-like coupling protein, respectively. The Mob proteins were predicted to mediate the formation of the relaxosome complex, nick DNA at the oriT, and shuttle the DNA/protein complex to the mating-pore apparatus. The results of mutational studies indicated that the three genes are required for maximal transfer of CTn341. Mob gene transcription was induced by tetracycline, and this regulation was mediated through the two-component regulatory system, RteAB. The oriT region of CTn341 was located within 100 bp of mobA, and a putative Bacteroides consensus nicking site was observed within this region. Mutation of the putative nick site resulted in a loss of transfer. This study demonstrated a role of the mobilization region for transfer of Bacteroides CTns and that tetracycline induction occurs for the mob gene operon, as for the tra gene operon(s), as shown previously. [ABSTRACT FROM AUTHOR]

Standard PCR (SPCR) and quantitative PCR (QPCR) assays using primers for general and for human-specific Bacteroides 16S rRNA markers were selected as the molecular tests to assess sewage contamination in recreational waters of Hawaii and these same water samples were assayed for culturable concentrations of selected faecal microbial indicators. The results of this study showed that the general primer for Bacteroides was not useful because ambient and polluted water samples were positive for this marker. However, use of human-specific primers reliably detected sewage contamination. The human-specific Bacteroides detection data supported previously reported conclusions that concentrations of alternative faecal indicators (C. perfringens, FRNA coliphages) but not traditional faecal indicators (faecal coliform, E. coil, enterococci) are reliable indicators of faecal contamination in Hawaii's environmental waters. The QPCR assay for the human-specific Bacteroides 16S rRNA marker was faster, more sensitive and more reliable than comparable SPCR assay because QPCR assay provided additional information such as melting temperatures, which confirmed that the right amplicons were being measured and Ct values, which indicated the relative level of faecal contamination. [ABSTRACT FROM AUTHOR]

Abstract: A group-specific PCR-based temperature gradient gel electrophoresis (TGGE) method was developed to study the population composition of genus Bacteroides in human gut. Highly reproducible and well-separated bands in TGGE fingerprints of ten unrelated human fecal samples showed complex and host-specific Bacteroides species composition. Dynamic monitoring over 22 months of samples from one healthy 10-year-old boy indicated a relatively stable population profile of Bacteroides. The species identity of each band in TGGE gel of this boy was also resolved via comigration analysis of sequenced inserts in a Bacteroides group-specific clone library. This work provides a rapid and effective technique for analyzing the species composition of Bacteroides in human gut. [Copyright &y& Elsevier]

Demonstrates that conjugal gene transfer has made a major contribution to increased antibiotic resistance in Bacteriodes species, a numerically predominant group of human colonic bacteria. Role of conjugative transposons and plasmids in the transfer of antibiotic resistance genes; Type of gene transfer elements associated with the horizontal gene transfer.

As part of a sustainable water resources management, the Lisbon municipality identified groundwater and treated wastewater use increase as two opportunities for better and sustainable water use, with natural safeguard for public health as a priority. In this context, the aim of our research was to assess the suitability of the human-associated marker gene Bacteroides HF183 and the cattle feces-associated CowM2, in routine water quality monitoring as indicators for water use and reuse, providing a tool to more accurately assess public health risks. To this intent, Real-Time quantitative PCR was used for detection of human-associated marker gene Bacteroides HF183 and the bovine-associated CowM2, in a total of 67 samples - groundwater and wastewater at three different treatment stages of a Waste Water Treatment Plant, in Lisbon. HF183 marker gene was detected in treated and untreated wastewater samples, with significant concentration reductions from untreated (6,07 E+07 copies/mL) to secondary treated effluent (1,86 E+05 copies/mL) and a further decrease in tertiary treatment (5,74 E+04 copies/mL). In groundwater samples, this marker was also detected in concentrations ranging from 2,63 E+02 copies/mL to 2,24 E+03 copies/mL. CowM2 marker gene on the other hand was only detected in wastewater samples, with concentrations ranging from 2,47 E+02 copies/mL to 1,17 E+04 copies/mL. Our research indicates that the use of Bacteroides spp. in association with traditional fecal indicator bacteria (FIB) is advantageous for water managing entities in urban settings, such as Lisbon, were drainage system failures may occur. An integrated approach thus provides crucial and more adequate information towards mitigation and correction measures when fecal contamination is detected in environmental waters. • Bacteroides were evaluated in an integrated hydric resources management approach. • Mutual detection of Bacteroides and FIB is advantageous for water managing entities. • HF183 marker was detected in groundwater, untreated and treated wastewater samples. • Identifying the origin of groundwater contamination allows correction measures. • HF183 marker may have a future role in evaluation of wastewater treatment. [ABSTRACT FROM AUTHOR]

Gut microbiota are significantly associated with the occurrence and development of inflammatory bowel disease (IBD). Panax notoginseng saponins (PNS) could be used for colitis and to modulate gut microbiota. However, the mechanism behind the effects of PNS on anti-colitis that are pertinent to gut microbiota is largely unknown. This study aimed to evaluate the anti-colitis effects of PNS and explore the involved mechanism as it is related to gut microbiota. Results showed that PNS significantly alleviated dextran sulfate sodium (DSS)-induced colitis. Meanwhile, after PNS treatment, the tight junction proteins were enhanced and proinflammatory cytokines, such as TNF- α , IL-6, IL-1 β , and IL-17, were decreased. Furthermore, Bacteroides spp. were significantly increased after modeling, while PNS reduced their abundance and significantly increased the amount of Akkermansia spp. in vivo. Importantly, Akkermansia spp. and Bacteroides spp. were correlated with the IBD disease indicators. Moreover, fecal microbiota transplantation (FMT) experiments confirmed that PNS-reshaped gut microbiota significantly alleviated DSS-induced colitis, while A. muciniphila significantly reduced the levels of the LPS-induced cellular inflammatory factors IL-1 β and TNF- α. In conclusion, PNS alleviated colitis pertinent to the upregulation of Akkermania spp. and downregulation of Bacteroides spp. in the gut. [ABSTRACT FROM AUTHOR]

The prevalence of resistance genes in two important anaerobic genera, Bacteroides and Prevotella , was assessed by applying PCR specifically directed to genes of interest. A total of 101 Bacteroides spp. and 99 Prevotella spp. human clinical isolates were identified using MALDI-TOF MS. The presence of the resistance genes cfxA , cepA , cfiA , tetQ , ermF and nim , was assessed. Prevalence of resistance genes was compared with the phenotypic resistance against amoxicillin, clindamycin, meropenem and metronidazole. Even though the majority of the Bacteroides isolates (95.0%) showed resistance towards amoxicillin, only 52/101 of the isolates harboured one of the resistance genes, accounting for this resistance. Within the genus Prevotella the presence of cfxA (50/99) almost perfectly matched the amoxicillin resistance (48/99). No difference in prevalence of the e rmF gene (16/101 and 9/99) and clindamycin resistance (16/101 and 10/99) was observed within Bacteroides and Prevotella , respectively. Two isolates of Prevotella were resistant to metronidazole. One harboured the nim gene. One metronidazole-susceptible isolate of Bacteroides harboured a nim gene. Within the Bacteroides and Prevotella genera, 6/101 strains and 5/99 isolates harboured three different resistance genes, respectively, among them tetQ. TetQ is often located on a conjugative transposon, increasing the chance of horizontal gene transfer between isolates. An unknown mechanism in Bacteroides non- fragilis isolates causes resistance to β-lactam antibiotics. The fact that the prevalence of the tetQ gene among Prevotella is increasing and the existence of isolates harbouring three resistance genes are worrisome developments. [ABSTRACT FROM AUTHOR]

Obligate anaerobic bacteria, including Bacteroides spp., have been known to be highly pathogenic in equine pleuropneumonia. Metronidazole and carbapenems are effective to control obligate anaerobic bacterial infection in humans. To determine an antimicrobial therapy for the infection of the pleural cavity of horse, pharmacokinetics (PK)/pharmacodynamics (PD) analysis was done based on pleural fluid concentrations of metronidazole and imipenem and their minimum inhibitory concentrations (MICs) against Bacteroides spp. isolated from horses with pleuropneumonia. Four horses were administered 15 mg/kg metronidazole orally and 10 mg/kg imipenem intravenously in a random crossover study design with a 4-week washout period between administrations. Pleural fluid was collected at 1, 3, and 8 h, and blood was collected at 0, 0.08, 0.17, 0.33, 0.5, 0.67, 0.83, 1, 1.25, 1.5, 2, 3, 4, 6, 8, 12 and 24h after drug administration. Drug concentrations were measured using high performance liquid chromatography. MICs of both antimicrobials against 22 Bacteroides spp. strains isolated from horses with pleuropneumonia were evaluated using gradient strip tests. The highest pleural concentrations of metronidazole and imipenem were 12.7 ± 3.3 μg/ml and 12.1 ± 0.9 μg/ml at 1 h after administration, respectively. The pleural concentrations of both antimicrobials were similar to the plasma concentrations at all time points, indicating that they were efficiently penetrated to the pleural fluid. The MIC90 values of metronidazole and imipenem were found to be 4 μg/ml and 0.5 μg/ml, respectively. It was indicated that the target PK/PD parameter for metronidazole was an AUC0-24 h/MIC ratio>70. PK simulation of metronidazole at a dose of 15 mg/kg at an 8-h interval administration indicated that the average AUC0-24 h was 339.6 μg.h/ml, and the AUC0-24h/MIC90 was found to be 84.9. In carbapenems, it was indicated that the target PK/PD parameter was time above MIC (TAM) > 50 % per day. The TAM of imipenem at a dose of 10 mg/kg at 8-h interval administration was 70.8 % per day. Thus, 15 mg/kg 8-hour interval metronidazole oral administration and 10 mg/kg 8-hour interval imipenem intravenous administration are expected to control Bacteroides spp. infection of the pleural cavity in horses. [ABSTRACT FROM AUTHOR]

Bacterial colonization of open wounds is common, and patients with infected wounds often report significantly elevated pain sensitivity at the wound site. Transient Receptor Potential Vanilloid Type 1 (TRPV1) channels are known to play an important role in pain signaling and may be sensitized under pro-inflammatory conditions. Bacterial membrane components, such as phosphoethanolamine dihydroceramide (PEDHC), phosphoglycerol dihydroceramide (PGDHC), and lipopolysaccharide (LPS), are released in the environment from the Gram-negative bacteria of the Bacteroidetes species colonizing the infected wounds. Here, we used intracellular calcium imaging and patch-clamp electrophysiology approaches to determine whether bacterially derived PEDHC, PGDHC, or LPS can modulate the activity of the TRPV1 channels heterologously expressed in HEK cells. We found that PEDHC and PGDHC can sensitize TRPV1 in a concentration-dependent manner, whereas LPS treatment does not significantly affect TRPV1 activity in HEK cells. We propose that sensitization of TRPV1 channels by Bacteroidetes-derived dihydroceramides may at least in part underlie the increased pain sensitivity associated with wound infections. [ABSTRACT FROM AUTHOR]

Ethanol extracts obtained from 13 poplar propolis samples originating from various European countries by traditional maceration were tested for total polyphenols, flavonoid content, and antioxidant activity. Moreover, the content of 18 polyphenolic compounds (from the group of phenolic acids and flavonoids) was determined using the HPLC method. The inhibitory effect of six selected extracts with the highest activity was assessed by well-diffusion method against five strains (Bifidobacterium spp., L. rhamnosus, L. acidophilus, E. coli, and Bacteroides spp.) of intestinal bacteria self-isolated from the faeces of obese probands with the use of selective media. It was found that the antioxidant activity of propolis varied depending on geographical origin and even among samples from the same region, which indicates that some other factors also influence propolis quality. The samples of different geographical origin varied mainly in the share of individual phenolic compounds, and it was not possible to find a characteristic marker of origin, excluding the galangin present in the Polish samples only. Assessing the inhibitory activity of propolis (in the range of 70 mg to 10 µg per mL) indicated that the concentration of 100 µg/mL was found as being safe for tested fecal bacteria (Bifidobacterium spp., L. rhamnosus, L. acidophilus, E. coli, and Bacteroides spp.). As no negative effect of low doses of propolis on the intestinal microflora was found, it can be suggested that its use in recommended doses brings only beneficial effects to the body. [ABSTRACT FROM AUTHOR]

Background and Aim: Ruminant enteric methane (CH4) is one of the largest sources of greenhouse gases that contribute to global warming. To minimize environmental harm caused by ruminants' CH4 production, natural substances can be used to suppress it. Chitosan from crustacean sources had been known to obstruct CH4 generation in the rumen. About 18% of silkworm pupae is chitin, but little is known about the impact of silkworm pupae chitosan on rumen methanogenesis. This study investigated the efficacy of the silkworm chitosan extraction method and its impact on rumen fermentation, methanogenesis, and microbial growth in vitro. Materials and Methods: This study employed a randomized complete block design featuring five treatments and four batches for rumen incubation as the blocking factor. In this study, five treatments were implemented: Control (CO) (basal diet with no added chitosan), basal diet with 6% chitosan from the Chinese Silkworm strain 804 (CHI804), basal diet with 6% chitosan from the PS 01 Hybrid Silkworm strain (CHIPS01), basal diet with 6% chitosan from the Hybrid F1 Japanese 102 x Chinese 202 races (CHIJC02), and basal diet with 6% commercial shrimp shell chitosan as the positive control (CHICOMM). The in vitro experiments assessed digestibility, pH, total gas generation, CH4 production, ammonia nitrogen (NH3-N), and short-chain fatty acid levels, along with microbial population. Data were analyzed using a general linear model followed by Duncan's test when applicable. Results: A significant effect on dry matter digestibility (DMD), total gas production, CH4, NH3-N, and rumen microbial populations (Methanogens, Ruminoccocus albus, Ruminoccocus flavefaciens, Selonomonas ruminantium, Butyrivibrio fibrisolvens, Streptoccocus bovis, Prevotella spp., and Bacteroides spp.) was observed (p < 0.05). The extracted chitosan (CHIJC02) used in this study exhibited a similar quality to that of commercial chitosan (CHICOMM). CHI804 treatment could reduce gas production, NH3-N production, and B. fibrisolvens population significantly (p < 0.05), while CHIJC02 could reduce CH4 production, methanogen population, acetate (C2) production, and increase propionate (C3) production significantly (p < 0.05). CHIJC02 and CHICOMM treatments could also increase the population of R. flavefaciens, S. ruminantium, and Bacteroides spp. significantly (p < 0.05). Chitosan addition significantly (p < 0.05) reduced DMD but did not impact organic matter digestibility or pH. Conclusion: The extracted chitosan mimics commercial chitosan in physico-chemical properties. Chitosan derived from Japanese and Chinese F1 hybrid silkworm strains demonstrated superior capacity for inhibiting CH4 generation compared to commercial chitosan. The quality and effects on methanogenesis, rumen fermentation, and rumen microbial populations can differ depending on the origin of chitosan. [ABSTRACT FROM AUTHOR]

Bacteroides vulgatus and Bacteroides uniformis are known to be abundant in the human fecal microbial community. Although these strains typically remain stable over time in humans, disruption of this microbial community following antibiotics resulted in the transient change to new strains suggesting that a complex, dynamic strain community exists in humans. To further study the selection of dominant fecal microbial strains from the gastrointestinal tract (GIT) community, we analyzed three longitudinal metagenomic sequencing data sets using BLAST+ to identify genes encoding Bacteroidales-specific antimicrobial proteins (BSAP) that have known functions to restrict species-specific replication of B. uniformis (BSAP-2) or B. vulgatus (BSAP-3) and have been postulated to provide a competitive advantage in microbial communities. In the HMP (Human Microbiome Project) data set, we found fecal samples from individuals had B. vulgatus or B. uniformis with either complete or deleted BSAP genes that did not change over time. We also examined fecal samples from two separate longitudinal data sets of individuals who had been given either single or multiple antibiotics. The BSAP gene pattern from most individuals given either single or multiple antibiotics recovered to be the same as the pre-antibiotic strain. However, in a few individuals, we found incomplete BSAP-3 genes at early times during the recovery that were replaced by B. vulgatus with the complete BSAP-3 gene, consistent with the function of the BSAP to specifically restrict Bacteroides spp. The results of these studies provide insights into the fluxes that occur in the Bacteroides spp. GIT community following perturbation and the dynamics of the selection of a dominant fecal strain of Bacteroides spp. [ABSTRACT FROM AUTHOR]

Abstract Microbial pollution of recreational waters poses a significant public health risk which, unless mitigated, will continue to increase with population growth. Water managers must implement strategies to accurately discriminate and source human from animal faecal contamination in complex urbanised environments. Our case-study used a new combination of chemical (i.e. ammonia) and microbial (i.e. Escherichia coli , Bacteroides spp.) faecal monitoring tools in a targeted multi-tiered approach to quickly identify pollution hot-spots and track high-risk subterranean stormwater drains in real-time. We successfully located three point sources of human faecal pollution (both episodic and constant pollution streams) within 11 catchments in a total monitoring time of four months. Alternative approaches for obtaining such fine-scale accuracy are typically labour intensive and require expensive equipment. Graphical abstract Unlabelled Image Highlights • A multi-tiered approach for real-time sourcing of human faecal pollution is proposed. • Chemical and microbial indicators were used as pollution identification tools. • A risk assessment framework allowed the detection of high-risk catchments. • A cracked sewer pipe and a sewer spill were located from 11 catchments in 4 months. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to investigate the bacterial strains that most commonly cause abscesses after failed endodontic treatment. Methodology: 102 pus samples from dentoalveolar abscesses were examined for bacterial growth. Additionally, 102 samples of healthy gingiva from the same patients were swabbed for comparison of etiology. The swabs were inoculated on blood, chocolate, and Schaedler agar plates; and incubated aerobically and anaerobically. Isolated pathogenic bacteria were compared to healthy oral flora from 50 healthy individuals. Bacterial strains were identified using the matrix assisted laser desorption ionization-time of flight (MALDI-TOF) method and susceptibility was tested using VITEK 2. Results: The same microorganism was identified from the healthy and abscess side of the oral cavity in 50.0% of the cases. The most commonly identified healthy aerobic flora were coagulase-negative staphylococci, alpha-hemolytic Streptococcus, Enterococcus, and Klebsiella spp. The most identified anaerobes were Actinomyces, Lactobacillus, and Bacteroides spp. Identification of 6 vancomycin-resistant Enterococcus, 3 amoxiclav resistant Actinomyces spp., 1 extended-spectrum beta-lactamases (ESBL) E. coli, and 2 ESBL Klebsiella spp. were confirmed. A significant correlation was found between prescription of amoxiclav before surgery and isolation of amoxiclav-resistant Actinomyces spp. (p = 0.035). Conclusions: Common oral flora caused dental abscesses. Not much antimicrobial resistance was detected among the bacterial isolates. However, the dentists used antibiotics irresponsibly because a few cases were identified where the bacteria were resistant to antibiotics used prior to removal of dentoalveolar abscesses. [ABSTRACT FROM AUTHOR]

The human gastrointestinal tract is a competitive environment inhabited by dense polymicrobial communities. Bacteroides, a genus of Gram-negative anaerobes, are prominent members of this ecological niche. Bacteroides spp. uses a repertoire of mechanisms to compete for resources within this environment such as the delivery of proteinaceous toxins into neighbouring competitor bacteria and the ability to consume unique metabolites available in the gut. In recent work, Bacteroides stercoris gut colonization was linked to the activity of a prophage-encoded ADP-ribosyltransferase, which was found to stimulate the release of the metabolite inosine from host epithelial cells. This fitness factor, termed Bxa, shares a similar genomic arrangement to bacterial toxins encoded within interbacterial antagonism loci. Here, we report that Bxa also possesses antibacterial ADP-ribosyltransferase activity, raising the question of how Bxa-producing bacteria resist intoxication prior to Bxa’s release from cells. To this end, we identify two cognate immunity proteins, Bsi and BAH, that neutralize Bxa’s antibacterial activity using distinct mechanisms. BAH acts as an enzymatic immunity protein that reverses Bxa ADPribosylation whereas Bsi physically interacts with Bxa and blocks its ADP-ribosylation activity. We also find that the Nterminal domain of Bxa is dispensable for toxicity and homologous domains in other bacteria are fused to a diverse array of predicted toxins found throughout the Bacteroidaceae, suggesting that Bxa belongs to a broader prophage encoded polymorphic toxin system. Overall, this work shows that Bxa is a promiscuous ADP-ribosyltransferase and that B. stercoris possesses mechanisms to protect itself from the toxic activity of this prophage encoded fitness factor. [ABSTRACT FROM AUTHOR]

Specific human gut microbes inhabit the outer mucus layer of the gastrointestinal tract. Certain residents of this niche can degrade the large and complex mucin glycoproteins that constitute this layer and utilise the degradation products for their metabolism. In turn, this microbial mucin degradation drives specific microbiological ecological interactions in the human gut mucus layer. However, the exact nature of these interactions remains unknown. In this study, we designed and studied an in vitro mucin-degrading synthetic community that included mucin O-glycan degraders and cross-feeding microorganisms by monitoring community composition and dynamics through a combination of 16S rRNA gene amplicon sequencing and qPCR, mucin glycan degradation with PGC-LC–MS/MS, production of mucin-degrading enzymes and other proteins through metaproteomics, and metabolite production with HPLC. We demonstrated that specialist and generalist mucin O-glycan degraders stably co-exist and found evidence for cross-feeding relationships. Cross-feeding on the products of mucin degradation by other gut microbes resulted in butyrate production, hydrogenotrophic acetogenesis, sulfate reduction and methanogenesis. Metaproteomics analysis revealed that mucin glycan degraders Akkermansia muciniphila , Bacteroides spp. and Ruminococcus torques together contributed 92% of the total mucin O-glycan degrading enzyme pool of this community. Furthermore, comparative proteomics showed that in response to cultivation in a community compared to monoculture, mucin glycan degraders increased carbohydrate-active enzymes whereas we also found indications for niche differentiation. These results confirm the complexity of mucin-driven microbiological ecological interactions and the intricate role of carbohydrate-active enzymes in the human gut mucus layer. [ABSTRACT FROM AUTHOR]

We investigated the epidemiology and antimicrobial susceptibility profiles of seven major Gram-negative bacilli (Escherichia coli , Klebsiella spp., Enterobacter spp., Pseudomonas aeruginosa , Acinetobacter spp., Stenotrophomonas maltophilia , and Bacteroides spp.) that caused bacteremia in Japan. We collected clinical information and isolates from patients aged 20 years or older who developed bacteremia during a year at three Japanese university hospitals and performed microbiological examination. In total, 628 cases were included, half of which were caused by E. coli (315 isolates). P. aeruginosa (56 isolates) was isolated most frequently among non-fermenting bacteria and 33 Bacteroides spp. were isolated. Mortality rates were the highest for P. aeruginosa (7-day, 16.1%; 30-day, 26.8%). The 7- and 30-day mortality rates ranged 3.8–9.0% and 8.3–17.6%, respectively, for Enterobacterales , and they were 15.2% each for Bacteroides spp. Regarding antimicrobial resistance, Enterobacterales and Acinetobacter spp. showed susceptibility to carbapenems and amikacin (98.0–100.0%). The susceptibility rates to ceftolozane/tazobactam ranged 82.4–99.0% for Enterobacterales and 92.9% for P. aeruginosa. More than 30.0% of E. coli isolates were resistant to fluoroquinolone. Extended-spectrum β-lactamase (ESBL) producers were found in 21.0% of E. coli and approximately 80% of those were resistant to fluoroquinolones. The susceptibility of the 33 Bacteroides spp. to carbapenems, ampicillin/sulbactam, and piperacillin/tazobactam was 100.0%. Among the ESBL producers, bla CTX-M group 9 was the major subgroup in E. coli (77.3%), and bla CTX-M group 1 was detected in 18.2% of E. coli and 50.0% of Klebsiella spp. Continuous surveillance is needed to understand the epidemiology and consider appropriate therapeutic strategies. [ABSTRACT FROM AUTHOR]

Biological aging is linked to altered body composition and reduced neuroactive steroid hormones like dehydroepiandrosterone sulfate (DHEAS), which can stimulate the GABA signaling pathway via gut microbiota. Our study examined the association of gut microbiota with lifespan in mice through comprehensive analysis of its composition and functional involvement in cholesterol sulfate, a precursor of DHEAS, metabolism. We used 16S rRNA and metagenomic sequencing, followed by metabolic pathway prediction and thin layer chromatography and MALDI-TOF cholesterol sulfate identification. Significant increases in bacteria such as Bacteroides , typical for long-lived and Odoribacter and Colidextribacter , specific for short-lived mice were detected. Furthermore, for males (Rikenella and Alloprevotella) and females (Lactobacillus and Bacteroides), specific bacterial groups emerged as predictors (AUC = 1), highlighting sex-specific patterns. Long-lived mice showed a strong correlation of Bacteroides (0.918) with lipid and steroid hormone metabolism, while a negative correlation of GABAergic synapse with body weight (−0.589). We found that several Bacteroides species harboring the sulfotransferase gene and gene cluster for sulfonate donor synthesis are involved in converting cholesterol to cholesterol sulfate, significantly higher in the feces of long-lived individuals. Overall, we suggest that increased involvement of gut bacteria, mainly Bacteroides spp. in cholesterol sulfate synthesis could ameliorate aging through lipid metabolism. [ABSTRACT FROM AUTHOR]

Pathogenic changes in gut microbial composition precede the onset of HIV-1 infection in men who have sex with men (MSM). This process is associated with increased levels of systemic inflammatory biomarkers and risk for AIDS development. Using mediation analysis framework, in this report we link the effects of unprotected receptive intercourse among MSM prior to primary HIV-1 infection to higher levels of proinflammatory cytokines sCD14 and sCD163 in plasma and a significant decrease in the abundance of A. muciniphila, B. caccae, B. fragilis, B. uniformis, Bacteroides spp., Butyricimonas spp., and Odoribacter spp., and a potential increase in the abundance of Dehalobacterium spp. and Methanobrevibacter spp. in stools of MSM with the highest number of sexual partners. These differences in microbiota, together with a reduction in the pairwise correlations among commensal and short-chain fatty acid-producing bacteria with a number of sexual partners, support an increase in gut dysbiosis with the number of sexual partners. These results demonstrate the interconnectedness of sexual behavior, immune response, and microbiota composition, notably among MSM participating in high-risk sexual behaviors. Sexual behavior among men who have receptive anal intercourse with men is linked to changes in the gut microbiome and systemic inflammation leading to HIV-1 infection. [ABSTRACT FROM AUTHOR]

Purpose: Impaired gut barrier function is associated with systemic inflammation and many chronic diseases. Undigested dietary proteins are fermented in the colon by the gut microbiota which produces nitrogenous metabolites shown to reduce barrier function in vitro. With growing evidence of sex-based differences in gut microbiotas, we determined whether there were sex by dietary protein interactions which could differentially impact barrier function via microbiota modification. Methods: Fermentation systems were inoculated with faeces from healthy males (n = 5) and females (n = 5) and supplemented with 0.9 g of non-hydrolysed proteins sourced from whey, fish, milk, soya, egg, pea, or mycoprotein. Microbial populations were quantified using fluorescence in situ hybridisation with flow cytometry. Metabolite concentrations were analysed using gas chromatography, solid phase microextraction coupled with gas chromatography-mass spectrometry and ELISA. Results: Increased protein availability resulted in increased proteolytic Bacteroides spp (p < 0.01) and Clostridium coccoides (p < 0.01), along with increased phenol (p < 0.01), p-cresol (p < 0.01), indole (p = 0.018) and ammonia (p < 0.01), varying by protein type. Counts of Clostridium cluster IX (p = 0.03) and concentration of p-cresol (p = 0.025) increased in males, while females produced more ammonia (p = 0.02), irrespective of protein type. Further, we observed significant sex-protein interactions affecting bacterial populations and metabolites (p < 0.005). Conclusions: Our findings suggest that protein fermentation by the gut microbiota in vitro is influenced by both protein source and the donor's sex. Should these results be confirmed through human studies, they could have major implications for developing dietary recommendations tailored by sex to prevent chronic illnesses. [ABSTRACT FROM AUTHOR]

Members of the genera Bacteroides and Parabacteroides are important constituents of both human and animal intestinal microbiota, and are significant facultative pathogens. In this study, the ability of Bacteroides spp. and Parabacteroides distasonis isolated from both diarrhoeal and normal stools ( n = 114) to adhere to and invade HEp-2 cells was evaluated. The presence of putative virulence factors such as capsule and fimbriae was also investigated. Adherence to HEp-2 cells was observed in 75.4% of the strains, which displayed non-localized clusters. Invasion was observed in 37.5% and 26% of the strains isolated from diarrhoeal and non-diarrhoeal stools, respectively. All strains displayed a capsule, whereas none of them showed fimbriae-like structures. This is the first report of the ability of Bacteroides spp. and P. distasonis to adhere to and invade cultured HEp-2 epithelial cells. [ABSTRACT FROM AUTHOR]

The article presents study that examine the effect of dietary supplementation with 1-kestose on the IgA levels in milk of lactating mice. The study shows that two-way ANOVA was performed with repeated measures at seven and 14 days after delivery and resulted in a significant effect of 1-kestose-supplementation on total IgA concentrations. It further states that a correlation was found between the mean count of Bacteroides spp. in maternal feces and the total IgA concentration in maternal milk.

Alveolar osteitis (AO) is one of the most common infectious complications after dental extractions. The data on the species composition of AO pathogens and their susceptibility to antimicrobial drugs can be the basis for their empirical use in case of inflammatory process aggravation. Objective. To determine the species composition and susceptibility to the antimicrobial agents of microorganisms, which were detected in patients with AO, who sought medical help in the oral surgery department of the dental medical center of Bogomolets National Medical University. Methods. Throughout 2018-2021, microbiological examination of tooth sockets from 30 patients with AO and 20 patients without AO was performed. The studied biological material was plated on appropriate nutrient media for isolation of aerobic, facultative and obligate-anaerobic microorganisms. Anaerobic conditions were achieved in GENbox 7.0 L and GENbox 2.5 L aerostats using GENbox anaerobic packages ("Biomerieux", France). The genus and species identity of the bacteria were determined according to Bergey. Antibiotic susceptibility of the isolated strains was determined by disk diffusion method. Results. It was found that most commonly microorganisms from tooth sockets in case of AO are: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus spp., Escherichia coli, Bacteroides spp., Clostridium spp., and Candida species, as well as their mixed cultures of 3-5 species of microorganisms. These aerobic and facultative anaerobic bacteria were susceptible to amoxicillin, ceftriaxone and ciprofloxacin in 92.6-100 % of cases. The growth of anaerobic bacteria in 100 % of cases was inhibited by colistin and meropenem. Conclusions. AO developing is caused by pathological colonization of socket of the extracted tooth by representatives of endogenous microbiota, namely Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus spp., Escherichia coli, which are present mainly in the mixed cultures with Candida albicans. For empirical antibiotic therapy of complicated forms of AO, amoxicillin or ceftriaxone or ciprofloxacin in complex with colistin or meropenem should be used, since these drugs suppress the growth of 92.6-100 % of strains of aerobic, facultative and obligate anaerobic microorganisms, which are potential pathogens of the purulent forms of AO. [ABSTRACT FROM AUTHOR]

Inbred mouse strains KK.Cg-a/a and KK.Cg-Ay/a known as genetic models of type 2 diabetes mellitus significantly surpassed the control strain C57BL/6J in the body weight, relative weight of extractable fat, and basal blood glucose levels. Real-timePCR of fecal samples from KK.Cg-a/a and KK.Cg-Ay/a mice revealed dysbiosis typical of type 2 diabetes mellitus in humans and animals. Long-term intragastric administration of a suspension of Hafnia alvei bacteria had no effect on the above morphometric and biochemical parameters. At the same time, recovery of the Bacteroides spp. population in KK.Cg-Ay/a mice and a decrease in the number of Bifidobacterium spp. in KK.Cg-a/a mice were observed. The possibility of therapeutic use of the probiotic based on H. alvei is discussed. [ABSTRACT FROM AUTHOR]

While most glycosidases that act on N‐linked glycans remove a single sugar residue at a time, endo‐α‐1,2‐mannosidases and endo‐α‐1,2‐mannanases of glycoside hydrolase family GH99 cut within a chain and remove two or more sugar residues. They are stereochemically retaining enzymes that use an enzymatic mechanism involving an epoxide intermediate. Human endo‐α‐1,2‐mannosidase (MANEA) trims glucosylated mannose residues; the endomannosidase pathway provides a glucosidase‐independent pathway for glycoprotein maturation. Cell‐active MANEA inhibitors alter N‐glycan processing and reduce infectivity of dengue virus, demonstrating that MANEA has potential as a host‐directed antiviral target. Sequence‐related enzymes from gut Bacteroides spp. exhibit endo‐α‐1,2‐mannosidase activity and are a fruitful test bed for structure‐guided inhibitor development. The genes encoding the Bacteroides spp. enzymes sit within polysaccharide utilization loci and are preferential endo‐α‐1,2‐mannanases. [ABSTRACT FROM AUTHOR]