scholarly journals Application of a Neutral Community Model To Assess Structuring of the Human Lung Microbiome

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Arvind Venkataraman ◽  
Christine M. Bassis ◽  
James M. Beck ◽  
Vincent B. Young ◽  
Jeffrey L. Curtis ◽  
...  

ABSTRACT DNA from phylogenetically diverse microbes is routinely recovered from healthy human lungs and used to define the lung microbiome. The proportion of this DNA originating from microbes adapted to the lungs, as opposed to microbes dispersing to the lungs from other body sites and the atmosphere, is not known. We use a neutral model of community ecology to distinguish members of the lung microbiome whose presence is consistent with dispersal from other body sites and those that deviate from the model, suggesting a competitive advantage to these microbes in the lungs. We find that the composition of the healthy lung microbiome is consistent with predictions of the neutral model, reflecting the overriding role of dispersal of microbes from the oral cavity in shaping the microbial community in healthy lungs. In contrast, the microbiome of diseased lungs was readily distinguished as being under active selection. We also assessed the viability of microbes from lung samples by cultivation with a variety of media and incubation conditions. Bacteria recovered by cultivation from healthy lungs represented species that comprised 61% of the 16S rRNA-encoding gene sequences derived from bronchoalveolar lavage samples.IMPORTANCE  Neutral distribution of microbes is a distinguishing feature of the microbiome in healthy lungs, wherein constant dispersal of bacteria from the oral cavity overrides differential growth of bacteria. No bacterial species consistently deviated from the model predictions in healthy lungs, although representatives of many of the dispersed species were readily cultivated. In contrast, bacterial populations in diseased lungs were identified as being under active selection. Quantification of the relative importance of selection and neutral processes such as dispersal in shaping the healthy lung microbiome is a first step toward understanding its impacts on host health.

1996 ◽  
Vol 30 (2) ◽  
pp. 108-113 ◽  
Author(s):  
L. Rodrigue ◽  
M. C. Lavoie

In order to assess the influence of the origin of mice on their oral bacteria, the proportions of bacterial species found in the oral cavity of BALB/c mice from 5 suppliers were determined. The results indicated that mice from different origins harboured different oral bacterial populations upon arrival at our animal facilities and the differences persisted for at least one week after arrival. Except in one case, the oral bacteria did not differ from one shipment to another from each supplier and remained similar after one week at our animal facilities. The results thus indicate that the composition of the oral bacterial population is influenced by the origin of the mice.


mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Daniel Montelongo-Jauregui ◽  
Stephen P. Saville ◽  
Jose L. Lopez-Ribot

ABSTRACTFungal and bacterial populations coexist in the oral cavity, frequently forming mixed-species biofilms that complicate treatment against polymicrobial infections. However, despite relevance to oral health, the bidirectional interactions between these microbial populations are poorly understood. In this study, we aimed to elucidate the mechanisms underlying the interactions between the fungal speciesCandida albicansand the bacterial speciesStreptococcus gordoniias they coexist in mixed-species biofilms. Specifically, the interactions of differentC. albicansmutant strains deficient in filamentation (efg1Δ/Δ andbrg1Δ/Δ), adhesive interactions (als3Δ/Δ andbcr1Δ/Δ), and production of matrix exopolymeric substances (EPS) (kre5Δ/Δ, mnn9Δ/Δ,rlm1Δ/Δ, andzap1Δ/Δ) were evaluated withS. gordoniiunder different conditions mimicking the environment in the oral cavity. Interestingly, our results revealed that growth of the biofilm-deficientC. albicansals3Δ/Δandbcr1Δ/Δmutant strains in synthetic saliva or withS. gordoniirestored their biofilm-forming ability. Moreover, challenging previous observations indicating an important role of morphogenetic conversions in the interactions between these two species, our results indicated a highly synergistic interaction betweenS. gordoniiand theC. albicansfilamentation-deficientefg1Δ/Δandbrg1Δ/Δdeletion mutants, which was particularly noticeable when the mixed biofilms were grown in synthetic saliva. Importantly, dual-species biofilms were found to exhibit increase in antimicrobial resistance, indicating that components of the fungal exopolymeric material confer protection to streptococcal cells against antibacterial treatment. Collectively, these findings unravel a high degree of complexity in the interactions betweenC. albicansandS. gordoniiin mixed-species biofilms, which may impact homeostasis in the oral cavity.IMPORTANCEMicrobial communities have a great impact in health and disease.C. albicansinteracts with multiple microorganisms in the oral cavity, frequently forming polymicrobial biofilms. We report on the synergistic interactions betweenC. albicansand the Gram-positive bacteriumS. gordonii, for which we have examined the different contributions of adhesive interactions, filamentation, and the extracellular matrix to the formation of dual-species biofilms. Our results demonstrate that growth in the presence of the bacterium can restore the biofilm-forming ability of differentC. albicansmutant strains with defects in adhesion and filamentation. The mixed-species biofilms also show high levels of resistance to antibacterial and antifungal antibiotics, and our results indicate that the fungal biofilm matrix protects bacterial cells within these mixed-species biofilms. Our observations add to a growing body of evidence indicating a high level of complexity in the reciprocal interactions and consortial behavior of fungal/bacterial biofilms.


2021 ◽  
Vol 22 (19) ◽  
pp. 10872
Author(s):  
Kazuma Yagi ◽  
Gary B. Huffnagle ◽  
Nicholas W. Lukacs ◽  
Nobuhiro Asai

Healthy human lungs have traditionally been considered to be a sterile organ. However, culture-independent molecular techniques have reported that large numbers of microbes coexist in the lung and airways. The lungs harbor diverse microbial composition that are undetected by previous approaches. Many studies have found significant differences in microbial composition between during health and respiratory disease. The lung microbiome is likely to not only influence susceptibility or causes of diseases but be affected by disease activities or responses to treatment. Although lung microbiome research has some limitations from study design to reporting, it can add further dimensionality to host-microbe interactions. Moreover, there is a possibility that extending understanding to the lung microbiome with new multiple omics approaches would be useful for developing both diagnostic and prognostic biomarkers for respiratory diseases in clinical settings.


Author(s):  
Brook A. Niemiec ◽  
Jerzy Gawor ◽  
Shuiquan Tang ◽  
Aishani Prem ◽  
Janina A. Krumbeck

Abstract OBJECTIVE To compare the bacteriome of the oral cavity in healthy dogs and dogs with various stages of periodontal disease. ANIMALS Dogs without periodontal disease (n = 12) or with mild (10), moderate (19), or severe (10) periodontal disease. PROCEDURES The maxillary arcade of each dog was sampled with a sterile swab, and swabs were submitted for next-generation DNA sequencing targeting the V1–V3 region of the 16S rRNA gene. RESULTS 714 bacterial species from 177 families were identified. The 3 most frequently found bacterial species were Actinomyces sp (48/51 samples), Porphyromonas cangingivalis (47/51 samples), and a Campylobacter sp (48/51 samples). The most abundant species were P cangingivalis, Porphyromonas gulae, and an undefined Porphyromonas sp. Porphyromonas cangingivalis and Campylobacter sp were part of the core microbiome shared among the 4 groups, and P gulae, which was significantly enriched in dogs with severe periodontal disease, was part of the core microbiome shared between all groups except dogs without periodontal disease. Christensenellaceae sp, Bacteroidales sp, Family XIII sp, Methanobrevibacter oralis, Peptostreptococcus canis, and Tannerella sp formed a unique core microbiome in dogs with severe periodontal disease. CONCLUSIONS AND CLINICAL RELEVANCE Results highlighted that in dogs, potential pathogens can be common members of the oral cavity bacteriome in the absence of disease, and changes in the relative abundance of certain members of the bacteriome can be associated with severity of periodontal disease. Future studies may aim to determine whether these changes are the cause or result of periodontal disease or the host immune response.


2018 ◽  
Vol 13 (14) ◽  
pp. 1611-1624 ◽  
Author(s):  
Maxime DM Fonkou ◽  
Jean-Charles Dufour ◽  
Grégory Dubourg ◽  
Didier Raoult

2018 ◽  
Vol 10 (464) ◽  
pp. eaal0033 ◽  
Author(s):  
Ahsan R. Akram ◽  
Sunay V. Chankeshwara ◽  
Emma Scholefield ◽  
Tashfeen Aslam ◽  
Neil McDonald ◽  
...  

Respiratory infections in mechanically ventilated patients caused by Gram-negative bacteria are a major cause of morbidity. Rapid and unequivocal determination of the presence, localization, and abundance of bacteria is critical for positive resolution of the infections and could be used for patient stratification and for monitoring treatment efficacy. Here, we developed an in situ approach to visualize Gram-negative bacterial species and cellular infiltrates in distal human lungs in real time. We used optical endomicroscopy to visualize a water-soluble optical imaging probe based on the antimicrobial peptide polymyxin conjugated to an environmentally sensitive fluorophore. The probe was chemically stable and nontoxic and, after in-human intrapulmonary microdosing, enabled the specific detection of Gram-negative bacteria in distal human airways and alveoli within minutes. The results suggest that pulmonary molecular imaging using a topically administered fluorescent probe targeting bacterial lipid A is safe and practical, enabling rapid in situ identification of Gram-negative bacteria in humans.


2008 ◽  
Vol 5 (6) ◽  
pp. 373 ◽  
Author(s):  
Roya Mortazavi ◽  
Christopher T. Hayes ◽  
Parisa A. Ariya

Environmental context. Biological ice nucleators have been found to freeze water at very warm temperatures. The potential of bio-aerosols to greatly influence cloud chemistry and microphysics is becoming increasingly apparent, yet detailed knowledge of their actual role in atmospheric processes is lacking. The formation of ice in the atmosphere has significant local, regional and global influence, ranging from precipitation to cloud nucleation and thus climate. Ice nucleation tests on bacteria isolated from snow and laboratory-grown bacteria, in comparison with those of known organic and inorganic aerosols, shed light on this issue. Abstract. Ice nucleation experiments on bacteria isolated from snow as well as grown in the laboratory, in comparison with those of known organic and inorganic aerosols, examined the importance of bio-aerosols on cloud processes. Snow samples were collected from urban and suburban sites in the greater Montreal region in Canada (45°28′N, 73°45′W). Among many snow bacterial isolates, eight types of bacterial species, none belonging to known effective ice nucleators such as Pseudomonas or Erwinia genera, were identified to show an intermediate range of ice nucleation activity (–12.9 ± 1.3°C to –17.5 ± 2.8°C). Comparable results were also obtained for molten snow samples and inorganic suspensions (kaolin and montmorillonite) of buffered water solutions. The presence of organic molecules (oxalic, malonic and succinic acids) had minimal effect (<2°C) on ice nucleation. Considering experimental limitations, and drawing from observation in snow samples of a variety of bacterial populations with variable ice-nucleation ability, a shift in airborne-species population may significantly alter glaciation processes in clouds.


2019 ◽  
Vol 18 ◽  
pp. 153303381986735 ◽  
Author(s):  
Indranil Chattopadhyay ◽  
Mukesh Verma ◽  
Madhusmita Panda

Despite advancement in cancer treatment, oral cancer has a poor prognosis and is often detected at late stage. To overcome these challenges, investigators should search for early diagnostic and prognostic biomarkers. More than 700 bacterial species reside in the oral cavity. The oral microbiome population varies by saliva and different habitats of oral cavity. Tobacco, alcohol, and betel nut, which are causative factors of oral cancer, may alter the oral microbiome composition. Both pathogenic and commensal strains of bacteria have significantly contributed to oral cancer. Numerous bacterial species in the oral cavity are involved in chronic inflammation that lead to development of oral carcinogenesis. Bacterial products and its metabolic by-products may induce permanent genetic alterations in epithelial cells of the host that drive proliferation and/or survival of epithelial cells. Porphyromonas gingivalis and Fusobacterium nucleatum induce production of inflammatory cytokines, cell proliferation, and inhibition of apoptosis, cellular invasion, and migration thorough host cell genomic alterations. Recent advancement in metagenomic technologies may be useful in identifying oral cancer–related microbiome, their genomes, virulence properties, and their interaction with host immunity. It is very important to address which bacterial species is responsible for driving oral carcinogenesis. Alteration in the oral commensal microbial communities have potential application as a diagnostic tool to predict oral squamous cell carcinoma. Clinicians should be aware that the protective properties of the resident microflora are beneficial to define treatment strategies. To develop highly precise and effective therapeutic approaches, identification of specific oral microbiomes may be required. In this review, we narrate the role of microbiome in the progression of oral cancer and its role as an early diagnostic and prognostic biomarker for oral cancer.


2021 ◽  
Vol 12 ◽  
Author(s):  
Rodrigo Cuiabano Paes Leme ◽  
Raquel Bandeira da Silva

It has been demonstrated that some non-steroidal anti-inflammatory drugs (NSAIDs), like acetylsalicylic acid, diclofenac, and ibuprofen, have anti-biofilm activity in concentrations found in human pharmacokinetic studies, which could fuel an interest in repurposing these well tolerated drugs as adjunctive therapies for biofilm-related infections. Here we sought to review the currently available data on the anti-biofilm activity of NSAIDs and its relevance in a clinical context. We performed a systematic literature review to identify the most commonly tested NSAIDs drugs in the last 5 years, the bacterial species that have demonstrated to be responsive to their actions, and the emergence of resistance to these molecules. We found that most studies investigating NSAIDs’ activity against biofilms were in vitro, and frequently tested non-clinical bacterial isolates, which may not adequately represent the bacterial populations that cause clinically-relevant biofilm-related infections. Furthermore, studies concerning NSAIDs and antibiotic resistance are scarce, with divergent outcomes. Although the potential to use NSAIDs to control biofilm-related infections seems to be an exciting avenue, there is a paucity of studies that tested these drugs using appropriate in vivo models of biofilm infections or in controlled human clinical trials to support their repurposing as anti-biofilm agents.


2021 ◽  
Author(s):  
Adam M. Blanchard ◽  
Ceri E. Staley ◽  
Laurence Shaw ◽  
Sean R Wattegedera ◽  
Christina-Marie Baumbach ◽  
...  

Footrot is a polymicrobial infectious disease in sheep causing severe lameness, leading to one of the industry’s biggest welfare problems. The complex aetiology of footrot makes in-situ or in-vitro investigations difficult. Computational methods offer a solution to understanding the bacteria involved, how they may interact with the host and ultimately providing a way to identify targets for future hypotheses driven investigative work. Here we present the first combined global analysis of the bacterial community transcripts together with the host immune response in healthy and diseased ovine feet during a natural polymicrobial infection state using metatranscriptomics. The intra tissue and surface bacterial populations and the most abundant bacterial transcriptome were analysed, demonstrating footrot affected skin has a reduced diversity and increased abundances of, not only the causative bacteria Dichelobacter nodosus , but other species such as Mycoplasma fermentans and Porphyromonas asaccharolytica . Host transcriptomics reveals a suppression of biological processes relating to skin barrier function, vascular functions, and immunosurveillance in unhealthy interdigital skin, supported by histological findings that type I collagen (associated with scar tissue formation) is significantly increased in footrot affected interdigital skin comparted to outwardly healthy skin. Finally, we provide some interesting indications of host and pathogen interactions associated with virulence genes and the host spliceosome which could lead to the identification of future therapeutic targets. Impact Statement Lameness in sheep is a global welfare and economic concern and footrot is the leading cause of lameness, affecting up to 70% of flocks in the U.K. Current methods for control of this disease are labour intensive and account for approximately 65% of antibiotic use in sheep farming, whilst preventative vaccines suffer from poor efficacy due to antigen competition. Our limited understanding of cofounders, such as strain variation and polymicrobial nature of infection mean new efficacious, affordable and scalable control measures are not receiving much attention. Here we examine the surface and intracellular bacterial populations and propose potential interactions with the host. Identification of these key bacterial species involved in the initiation and progression of disease and the host immune mechanisms could help form the basis of new therapies.


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