scholarly journals The Human Skin Microbiome Associates with the Outcome of and Is Influenced by Bacterial Infection

mBio ◽  
2015 ◽  
Vol 6 (5) ◽  
Author(s):  
Julia J. van Rensburg ◽  
Huaiying Lin ◽  
Xiang Gao ◽  
Evelyn Toh ◽  
Kate R. Fortney ◽  
...  
Keyword(s):  
Human Skin ◽  
Bacterial Species ◽  
Haemophilus Ducreyi ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Multiple Time ◽  
Skin Microbiome ◽  
Skin Microbiota ◽  
Content Type ◽  
Curtis Dissimilarity

ABSTRACTThe influence of the skin microbiota on host susceptibility to infectious agents is largely unexplored. The skin harbors diverse bacterial species that may promote or antagonize the growth of an invading pathogen. We developed a human infection model forHaemophilus ducreyiin which human volunteers are inoculated on the upper arm. After inoculation, papules form and either spontaneously resolve or progress to pustules. To examine the role of the skin microbiota in the outcome ofH. ducreyiinfection, we analyzed the microbiomes of four dose-matched pairs of “resolvers” and “pustule formers” whose inoculation sites were swabbed at multiple time points. Bacteria present on the skin were identified by amplification and pyrosequencing of 16S rRNA genes. Nonmetric multidimensional scaling (NMDS) using Bray-Curtis dissimilarity between the preinfection microbiomes of infected sites showed that sites from the same volunteer clustered together and that pustule formers segregated from resolvers (P= 0.001, permutational multivariate analysis of variance [PERMANOVA]), suggesting that the preinfection microbiomes were associated with outcome. NMDS using Bray-Curtis dissimilarity of the endpoint samples showed that the pustule sites clustered together and were significantly different than the resolved sites (P= 0.001, PERMANOVA), suggesting that the microbiomes at the endpoint differed between the two groups. In addition toH. ducreyi, pustule-forming sites had a greater abundance ofProteobacteria,Bacteroidetes,Micrococcus,Corynebacterium,Paracoccus, andStaphylococcusspecies, whereas resolved sites had higher levels ofActinobacteriaandPropionibacteriumspecies. These results suggest that at baseline, resolvers and pustule formers have distinct skin bacterial communities which change in response to infection and the resultant immune response.IMPORTANCEHuman skin is home to a diverse community of microorganisms, collectively known as the skin microbiome. Some resident bacteria are thought to protect the skin from infection by outcompeting pathogens for resources or by priming the immune system's response to invaders. However, the influence of the skin microbiome on the susceptibility to or protection from infection has not been prospectively evaluated in humans. We characterized the skin microbiome before, during, and after experimental inoculation of the arm withHaemophilus ducreyiin matched volunteers who subsequently resolved the infection or formed abscesses. Our results suggest that the preinfection microbiomes of pustule formers and resolvers have distinct community structures which change in response to the progression ofH. ducreyiinfection to abscess formation.

scholarly journals Comprehensive skin microbiome analysis reveals the uniqueness of human skin and evidence for phylosymbiosis within the class Mammalia

2018 ◽  
Vol 115 (25) ◽  
pp. E5786-E5795 ◽  
Author(s):  
Ashley A. Ross ◽  
Kirsten M. Müller ◽  
J. Scott Weese ◽  
Josh D. Neufeld
Keyword(s):  
Microbial Community ◽  
Microbial Communities ◽  
Human Skin ◽  
Microbial Community Composition ◽  
Geographic Location ◽  
The Body ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Skin Microbiome ◽  
Skin Microbiota

Skin is the largest organ of the body and represents the primary physical barrier between mammals and their external environment, yet the factors that govern skin microbial community composition among mammals are poorly understood. The objective of this research was to generate a skin microbiota baseline for members of the class Mammalia, testing the effects of host species, geographic location, body region, and biological sex. Skin from the back, torso, and inner thighs of 177 nonhuman mammals was sampled, representing individuals from 38 species and 10 mammalian orders. Animals were sampled from farms, zoos, households, and the wild. The DNA extracts from all skin swabs were amplified by PCR and sequenced, targeting the V3-V4 regions of bacterial and archaeal 16S rRNA genes. Previously published skin microbiome data from 20 human participants, sampled and sequenced using an identical protocol to the nonhuman mammals, were included to make this a comprehensive analysis. Human skin microbial communities were distinct and significantly less diverse than all other sampled mammalian orders. The factor most strongly associated with microbial community data for all samples was whether the host was a human. Within nonhuman samples, host taxonomic order was the most significant factor influencing skin microbiota, followed by the geographic location of the habitat. By comparing the congruence between host phylogeny and microbial community dendrograms, we observed that Artiodactyla (even-toed ungulates) and Perissodactyla (odd-toed ungulates) had significant congruence, providing evidence of phylosymbiosis between skin microbial communities and their hosts.

scholarly journals Microbiome Data Distinguish Patients with Clostridium difficile Infection and Non-C. difficile-Associated Diarrhea from Healthy Controls

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Alyxandria M. Schubert ◽  
Mary A. M. Rogers ◽  
Cathrin Ring ◽  
Jill Mogle ◽  
Joseph P. Petrosino ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Bacterial Species ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Colonization Resistance ◽  
Bacterial Populations ◽  
Content Type ◽  
Increased Risk ◽  
Community Types ◽  
Microbiome Data

ABSTRACTAntibiotic usage is the most commonly cited risk factor for hospital-acquiredClostridium difficileinfections (CDI). The increased risk is due to disruption of the indigenous microbiome and a subsequent decrease in colonization resistance by the perturbed bacterial community; however, the specific changes in the microbiome that lead to increased risk are poorly understood. We developed statistical models that incorporated microbiome data with clinical and demographic data to better understand why individuals develop CDI. The 16S rRNA genes were sequenced from the feces of 338 individuals, including cases, diarrheal controls, and nondiarrheal controls. We modeled CDI and diarrheal status using multiple clinical variables, including age, antibiotic use, antacid use, and other known risk factors using logit regression. This base model was compared to models that incorporated microbiome data, using diversity metrics, community types, or specific bacterial populations, to identify characteristics of the microbiome associated with CDI susceptibility or resistance. The addition of microbiome data significantly improved our ability to distinguish CDI status when comparing cases or diarrheal controls to nondiarrheal controls. However, only when we assigned samples to community types was it possible to differentiate cases from diarrheal controls. Several bacterial species within theRuminococcaceae,Lachnospiraceae,Bacteroides, andPorphyromonadaceaewere largely absent in cases and highly associated with nondiarrheal controls. The improved discriminatory ability of our microbiome-based models confirms the theory that factors affecting the microbiome influence CDI.IMPORTANCEThe gut microbiome, composed of the trillions of bacteria residing in the gastrointestinal tract, is responsible for a number of critical functions within the host. These include digestion, immune system stimulation, and colonization resistance. The microbiome’s role in colonization resistance, which is the ability to prevent and limit pathogen colonization and growth, is key for protection againstClostridium difficileinfections. However, the bacteria that are important for colonization resistance have not yet been elucidated. Using statistical modeling techniques and different representations of the microbiome, we demonstrated that several community types and the loss of several bacterial populations, includingBacteroides,Lachnospiraceae, andRuminococcaceae, are associated with CDI. Our results emphasize the importance of considering the microbiome in mediating colonization resistance and may also direct the design of future multispecies probiotic therapies.

scholarly journals Microbial Infections Are Associated with Embryo Mortality in Arctic-Nesting Geese

2015 ◽  
Vol 81 (16) ◽  
pp. 5583-5592 ◽  
Author(s):  
Cristina M. Hansen ◽  
Brandt W. Meixell ◽  
Caroline Van Hemert ◽  
Rebekah F. Hare ◽  
Karsten Hueffer
Keyword(s):  
Bacterial Infections ◽  
Bacterial Species ◽  
Breeding Population ◽  
16S Rrna Genes ◽  
The Arctic ◽  
Rrna Genes ◽  
Culture Methods ◽  
Embryo Mortality ◽  
Content Type ◽  
Streptococcus Uberis

ABSTRACTTo address the role of bacterial infection in hatching failure of wild geese, we monitored embryo development in a breeding population of Greater white-fronted geese (Anser albifrons) on the Arctic Coastal Plain of Alaska. During 2013, we observed mortality of normally developing embryos and collected 36 addled eggs for analysis. We also collected 17 infertile eggs for comparison. Using standard culture methods and gene sequencing to identify bacteria within collected eggs, we identified a potentially novel species ofNeisseriain 33 eggs,Macrococcus caseolyticusin 6 eggs, andStreptococcus uberisandRothia nasimuriumin 4 eggs each. We detected seven other bacterial species at lower frequencies. Sequences of the 16S rRNA genes from theNeisseriaisolates most closely matched sequences fromN. animalorisandN. canis(96 to 97% identity), but phylogenetic analysis suggested substantial genetic differentiation between egg isolates and knownNeisseriaspecies. Although definitive sources of the bacteria remain unknown, we detectedNeisseriaDNA from swabs of eggshells, nest contents, and cloacae of nesting females. To assess the pathogenicity of bacteria identified in contents of addled eggs, we inoculated isolates ofNeisseria,Macrococcus,Streptococcus, andRothiaat various concentrations into developing chicken eggs. Seven-day mortality rates varied from 70 to 100%, depending on the bacterial species and inoculation dose. Our results suggest that bacterial infections are a source of embryo mortality in wild geese in the Arctic.

scholarly journals RNA–Stable-Isotope Probing Shows Utilization of Carbon from Inulin by Specific Bacterial Populations in the Rat Large Bowel

2014 ◽  
Vol 80 (7) ◽  
pp. 2240-2247 ◽  
Author(s):  
Gerald W. Tannock ◽  
Blair Lawley ◽  
Karen Munro ◽  
Ian M. Sims ◽  
Julian Lee ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Bacterial Species ◽  
Buoyant Density ◽  
Stable Isotope Probing ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Bacterial Cells ◽  
Bacterial Populations ◽  
Content Type ◽  
And Function

ABSTRACTKnowledge of the trophisms that underpin bowel microbiota composition is required in order to understand its complex phylogeny and function. Stable-isotope (13C)-labeled inulin was added to the diet of rats on a single occasion in order to detect utilization of inulin-derived substrates by particular members of the cecal microbiota. Cecal digesta from Fibruline-inulin-fed rats was collected prior to (0 h) and at 6, 12, 18 and 24 h following provision of the [13C]inulin diet. RNA was extracted from these cecal specimens and fractionated in isopycnic buoyant density gradients in order to detect13C-labeled nucleic acid originating in bacterial cells that had metabolized the labeled dietary constituent. RNA extracted from specimens collected after provision of the labeled diet was more dense than 0-h RNA. Sequencing of 16S rRNA genes amplified from cDNA obtained from these fractions showed thatBacteroides uniformis,Blautia glucerasea,Clostridium indolis, andBifidobacterium animaliswere the main users of the13C-labeled substrate. Culture-based studies of strains of these bacterial species enabled trophisms associated with inulin and its hydrolysis products to be identified.B. uniformisutilized Fibruline-inulin for growth, whereas the other species used fructo-oligosaccharide and monosaccharides. Thus, RNA–stable-isotope probing (RNA-SIP) provided new information about the use of carbon from inulin in microbiota metabolism.

scholarly journals Cutibacterium acnes (Propionibacterium acnes) 16S rRNA Genotyping of Microbial Samples from Possessions Contributes to Owner Identification

mSystems ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Jiayue Yang ◽  
Tomoya Tsukimi ◽  
Mia Yoshikawa ◽  
Kenta Suzuki ◽  
Tomoki Takeda ◽  
...  
Keyword(s):  
16S Rrna ◽  
Human Skin ◽  
Rrna Gene ◽  
Skin Microbiome ◽  
Nucleotide Polymorphisms ◽  
Skin Microbiota ◽  
Content Type ◽  
Microbiome Profile ◽  
Cutibacterium Acnes ◽  
Genotype Composition

ABSTRACT The human skin surface harbors huge numbers of microbes. The skin microbiota interacts with its host and forms a skin microbiome profile that is specific for each individual. It has been reported that the skin microbiota that is left on an individual’s possessions can act as a sort of “fingerprint” and be used for owner identification. However, this approach needs to be improved to take into account any long-term instability of skin microbiota and contamination from nonspecific bacteria. Here, we took advantage of single-nucleotide polymorphisms (SNPs) in the 16S-encoding rRNA gene of Cutibacterium acnes, the most common and abundant bacterium on human skin, to perform owner identification. We first developed a high-throughput genotyping method based on next-generation sequencing to characterize the SNPs of the C. acnes 16S rRNA gene and found that the genotype composition of C. acnes 16S rRNA is individual specific. Owner identification accuracy of around 90% based on random forest machine learning was achieved by using a combination of C. acnes 16S rRNA genotype and skin microbiome profile data. Furthermore, our study showed that the C. acnes 16S rRNA genotype remained more stable over time than the skin microbiome profile. This characteristic of C. acnes was further confirmed by the analysis of publicly available human skin metagenome data. Our approach, with its high precision, good reproducibility, and low costs, thus provides new possibilities in the field of microbiome-based owner identification and forensics in general. IMPORTANCE Cutibacterium acnes is the most common and abundant bacterial species on human skin, and the gene that encodes its 16S rRNA has multiple single-nucleotide polymorphisms. In this study, we developed a method to efficiently determine the C. acnes 16S rRNA genotype composition from microbial samples taken from the hands of participants and from their possessions. Using the C. acnes 16S rRNA genotype composition, we could predict the owner of a possession with around 90% accuracy when the 16S rRNA gene-based microbiome profile was included. We also showed that the C. acnes 16S rRNA genotype composition was more stable over time than the skin microbiome profile and thus is more suitable for owner identification.

scholarly journals Complete Genome Sequence of Malassezia restricta CBS 7877, an Opportunist Pathogen Involved in Dandruff and Seborrheic Dermatitis

2019 ◽  
Vol 8 (6) ◽  
Author(s):  
Stanislas C. Morand ◽  
Morgane Bertignac ◽  
Agnes Iltis ◽  
Iris C. R. M. Kolder ◽  
Walter Pirovano ◽  
...  
Keyword(s):  
Human Skin ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Seborrheic Dermatitis ◽  
Skin Microbiome ◽  
Basidiomycetous Yeasts ◽  
Content Type ◽  
Opportunist Pathogen ◽  
Malassezia Restricta

Malassezia restricta, one of the predominant basidiomycetous yeasts present on human skin, is involved in scalp disorders. Here, we report the complete genome sequence of the lipophilic Malassezia restricta CBS 7877 strain, which will facilitate the study of the mechanisms underlying its commensal and pathogenic roles within the skin microbiome.

scholarly journals Consistent Metagenome-Derived Metrics Verify and Delineate Bacterial Species Boundaries

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Matthew R. Olm ◽  
Alexander Crits-Christoph ◽  
Spencer Diamond ◽  
Adi Lavy ◽  
Paula B. Matheus Carnevali ◽  
...  
Keyword(s):  
Bacterial Diversity ◽  
Ribosomal Proteins ◽  
Large Scale ◽  
Bacterial Species ◽  
Bacterial Genome ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Species Discrimination ◽  
Bacterial Genomes ◽  
Discrimination Power

ABSTRACT Longstanding questions relate to the existence of naturally distinct bacterial species and genetic approaches to distinguish them. Bacterial genomes in public databases form distinct groups, but these databases are subject to isolation and deposition biases. To avoid these biases, we compared 5,203 bacterial genomes from 1,457 environmental metagenomic samples to test for distinct clouds of diversity and evaluated metrics that could be used to define the species boundary. Bacterial genomes from the human gut, soil, and the ocean all exhibited gaps in whole-genome average nucleotide identities (ANI) near the previously suggested species threshold of 95% ANI. While genome-wide ratios of nonsynonymous and synonymous nucleotide differences (dN/dS) decrease until ANI values approach ∼98%, two methods for estimating homologous recombination approached zero at ∼95% ANI, supporting breakdown of recombination due to sequence divergence as a species-forming force. We evaluated 107 genome-based metrics for their ability to distinguish species when full genomes are not recovered. Full-length 16S rRNA genes were least useful, in part because they were underrecovered from metagenomes. However, many ribosomal proteins displayed both high metagenomic recoverability and species discrimination power. Taken together, our results verify the existence of sequence-discrete microbial species in metagenome-derived genomes and highlight the usefulness of ribosomal genes for gene-level species discrimination. IMPORTANCE There is controversy about whether bacterial diversity is clustered into distinct species groups or exists as a continuum. To address this issue, we analyzed bacterial genome databases and reports from several previous large-scale environment studies and identified clear discrete groups of species-level bacterial diversity in all cases. Genetic analysis further revealed that quasi-sexual reproduction via horizontal gene transfer is likely a key evolutionary force that maintains bacterial species integrity. We next benchmarked over 100 metrics to distinguish these bacterial species from each other and identified several genes encoding ribosomal proteins with high species discrimination power. Overall, the results from this study provide best practices for bacterial species delineation based on genome content and insight into the nature of bacterial species population genetics.

scholarly journals Treatment nonresponse in children receiving silver diamine fluoride for caries: A pilot study

2020 ◽  
Author(s):  
Ryan Richard Ruff ◽  
Bidisha Paul ◽  
Maria A Sierra ◽  
Fangxi Xu ◽  
Yasmi Crystal ◽  
...  
Keyword(s):  
Pilot Study ◽  
Bacterial Species ◽  
Illumina Miseq ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Lasso Regression ◽  
Silver Diamine Fluoride ◽  
Operational Taxonomic Units ◽  
Acid Tolerant ◽  
Nonsurgical Therapy

AbstractObjectives: Silver diamine fluoride (SDF) is a nonsurgical therapy for the arrest and prevention of dental caries with demonstrated clinical efficacy. Approximately 20% of children receiving SDF fail to respond to treatment. The objective of this study was to develop a predictive model of treatment nonresponse using machine learning. Methods: An observational pilot study (N=20) consisting of children with and without active decay and who did and did not respond to silver diamine fluoride provided salivary samples and plaque from infected and contralateral sites. 16S rRNA genes from samples were amplified and sequenced on an Illumina Miseq and analyzed using QIIME. The association between operational taxonomic units and treatment nonresponse was assessed using lasso regression and artificial neural networks. Results: Bivariate group comparisons of bacterial abundance indicate a number of genera were significantly different between nonresponders and those who responded to SDF therapy. No differences were found between nonresponders and caries-active subjects. Prevotella pallens and Veillonella denticariosi were retained in full lasso models and combined with clinical variables in a six-input multilayer perceptron. Discussion: The acidogenic and acid-tolerant nature of retained bacterial species may overcome the antimicrobial effects of SDF. Further research to validate the model in larger external samples is needed.

scholarly journals Rhizobium azibense sp. nov., a nitrogen fixing bacterium isolated from root-nodules of Phaseolus vulgaris

2014 ◽  
Vol 64 (Pt_5) ◽  
pp. 1501-1506 ◽  
Author(s):  
Bacem Mnasri ◽  
Tian Yan Liu ◽  
Sabrine Saidi ◽  
Wen Feng Chen ◽  
Wen Xin Chen ◽  
...  
Keyword(s):  
Type Species ◽  
Root Nodules ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
The Novel ◽  
Content Type ◽  
Link Type ◽  
Physiological Properties ◽  
Microbial Strains ◽  
Type Strains

Three microbial strains isolated from common beans, 23C2T (Tunisia), Gr42 (Spain) and IE4868 (Mexico), which have been identified previously as representing a genomic group closely related to Rhizobium gallicum , are further studied here. Their 16S rRNA genes showed 98.5–99 % similarity with Rhizobium loessense CCBAU 7190BT, R. gallicum R602spT, Rhizobium mongolense USDA 1844T and Rhizobium yanglingense CCBAU 71623T. Phylogenetic analysis based on recA, atpD, dnaK and thrC sequences showed that the novel strains were closely related and could be distinguished from the four type strains of the closely related species. Strains 23C2T, Gr42 and IE4868 could be also differentiated from their closest phylogenetic neighbours by their phenotypic and physiological properties and their fatty acid contents. All three strains harboured symbiotic genes specific to biovar gallicum. Levels of DNA–DNA relatedness between strain 23C2T and the type strains of R. loessense , R. mongolense , R. gallicum and R. yanglingense ranged from 58.1 to 61.5 %. The DNA G+C content of the genomic DNA of strain 23C2T was 59.52 %. On the basis of these data, strains 23C2T, Gr42 and IE4868 were considered to represent a novel species of the genus Rhizobium for which the name Rhizobium azibense is proposed. Strain 23C2T ( = CCBAU 101087T = HAMBI3541T) was designated as the type strain.

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