The Microbiome of Osteoarthritic Hip and Knee Joints: A Prospective Multicenter Investigation.

BACKGROUND: Recent advances in high-throughput DNA sequencing technologies have made it possible to characterize the microbial profile in anatomical sites previously assumed to be sterile. We used this approach to explore the microbial composition within joints of osteoarthritic patients. METHODS: This prospective multicenter study recruited 113 patients undergoing hip or knee arthroplasty between 2017 and 2019. Demographics and prior intra-articular injections were noted. Matched synovial fluid, tissue, and swab specimens were obtained and shipped to a centralized laboratory for testing. Following DNA extraction, microbial 16S-rRNA sequencing was performed. RESULTS: Comparisons of paired specimens indicated that each was a comparable measure for microbiological sampling of the joint. Swab specimens were modestly different in bacterial composition from synovial fluid and tissue. The 5 most abundant genera were Escherichia, Cutibacterium, Staphylococcus, Acinetobacter, and Pseudomonas. Although sample size varied, the hospital of origin explained a significant portion (18.5%) of the variance in the microbial composition of the joint, and corticosteroid injection within 6 months before arthroplasty was associated with elevated abundance of several lineages. CONCLUSIONS: The findings revealed that prior intra-articular injection and the operative hospital environment may influence the microbial composition of the joint. Furthermore, the most common species observed in this study were not among the most common in previous skin microbiome studies, suggesting that the microbial profiles detected are not likely explained solely by skin contamination. Further research is needed to determine the relationship between the hospital and a "closed" microbiome environment. These findings contribute to establishing the baseline microbial signal and identifying contributing variables in the osteoarthritic joint, which will be valuable as a comparator in the contexts of infection and long-term arthroplasty success. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Molecular testing with next-generation sequencing appears to identify biofilm on penile prostheses better than traditional cultures: The new gold standard?

INTRODUCTION: Traditional culture is the current standard-of-care to determine therapeutic antibiotics for patients suffering from penile prostheses (PP) infections. However, approximately 50% of PPs removed for infection are culture negative. Next-generation sequencing (NGS) compares DNA sequences to reference sequences with known microbial taxonomies to identify isolates and report relative abundances. We aim to compare the ability for standard culture and NGS techniques to identify microorganisms and biofilm composition on PPs. MATERIALS AND METHODS: Ninety-one PPs explanted for mechanical malfunction were included in this study. Devices removed for infection or erosion were excluded. During revision surgery, two specimens were collected and sent for culture testing at institutional laboratory and for NGS testing (MicroGenDx, Lubbock, TX, USA). Species' relative abundances, sample diversity and richness, and compositional differences among samples were analyzed. RESULTS: NGS had a higher rate of microbial detection (n = 72, 79.1%) compared to culture results (n = 3, 3.3%). Some of the bacteria identified using both methods were known prosthetic infectious pathogens, with NGS producing more isolates (mean: 11) than culture (mean: 1). Escherichia coli was the most abundant and most frequently occurring bacteria detected on NGS. Coagulase-negative Staphylococci were the most common bacteria detected on traditional culture. CONCLUSIONS: NGS appears to be beneficial in its thorough analysis of PP biofilm composition when compared to culture methods. We hope that further research will be able to demonstrate a clinical benefit of NGS in characterizing distinct microbiomes and biofilms of infected PP, which can aid in tailoring antimicrobial therapy and improving patient outcomes.

An Enhanced Understanding of Culture-Negative Periprosthetic Joint Infection with Next-Generation Sequencing: A Multicenter Study.

BACKGROUND: The challenges of culture-negative periprosthetic joint infection (PJI) have led to the emergence of molecular methods of pathogen identification, including next-generation sequencing (NGS). While its increased sensitivity compared with traditional culture techniques is well documented, it is not fully known which organisms could be expected to be detected with use of NGS. The aim of this study was to describe the NGS profile of culture-negative PJI. METHODS: Patients undergoing revision hip or knee arthroplasty from June 2016 to August 2020 at 14 institutions were prospectively recruited. Patients meeting International Consensus Meeting (ICM) criteria for PJI were included in this study. Intraoperative samples were obtained and concurrently sent for both routine culture and NGS. Patients for whom NGS was positive and standard culture was negative were included in our analysis. RESULTS: The overall cohort included 301 patients who met the ICM criteria for PJI. Of these patients, 85 (28.2%) were culture-negative. A pathogen could be identified by NGS in 56 (65.9%) of these culture-negative patients. Seventeen species were identified as common based on a study-wide incidence threshold of 5%. NGS revealed a polymicrobial infection in 91.1% of culture-negative PJI cases, with the set of common species contributing to 82.4% of polymicrobial profiles. Escherichia coli, Cutibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus ranked highest in terms of incidence and study-wide mean relative abundance and were most frequently the dominant organism when occurring in polymicrobial infections. CONCLUSIONS: NGS provides a more comprehensive picture of the microbial profile of infection that is often missed by traditional culture. Examining the profile of PJI in a multicenter cohort using NGS, this study demonstrated that approximately two-thirds of culture-negative PJIs had identifiable opportunistically pathogenic organisms, and furthermore, the majority of infections were polymicrobial. LEVEL OF EVIDENCE: Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Diets Containing Egg or Whey Protein and Inulin Fiber Improve Energy Balance and Modulate Gut Microbiota in Exercising Obese Rats.

SCOPE: Dietary protein, prebiotic fiber, and exercise individually have been shown to aid in weight loss; however less is known of their combined effects on energy balance. The effects of diets high in protein and fiber, with exercise, on energy balance, hormones, and gut microbiota, were determined. METHODS AND RESULTS: Obese male rats were fed high-fat diets with high protein and fiber contents from egg protein and cellulose, egg protein and inulin, whey protein and cellulose, or whey protein and inulin, together with treadmill exercise. We found that inulin enriched diets decreased energy intake and respiratory quotient (RQ), increased energy expenditure (EE), and upregulated transcripts for cholecystokinin (CCK), peptide YY, and proglucagon in distal gut. Notably, CCK1-receptor blockade attenuated the hypophagic effects of diets and in particular whey-inulin diet, and ß-adrenergic blockade reduced EE across all diets. Egg-cellulose, egg-inulin, and whey-inulin diets decreased weight gain, adiposity, and hepatic lipidosis; decreased lipogenic transcripts, improved glycemic control, and upregulated hepatic glucose metabolism transcripts; and decreased plasma insulin and leptin. Importantly, diet was linked to altered gut microbial composition and plasma metabolomics, and a subset of predicted metagenome pathways and plasma metabolites significantly correlated, with plasma butyric acid the most strongly associated to metagenome function. CONCLUSION: Combination of dietary egg or whey protein with inulin and exercise improved energy balance, glucose metabolism, upregulated anorectic hormones, and selectively modulated gut microbiota and plasma metabolites.

Dietary whey and egg proteins interact with inulin fiber to modulate energy balance and gut microbiota in obese rats.

Diets supplemented with protein and fiber are well known to reduce food intake and weight gain; however, less is known about the combined effects of protein and prebiotic fiber on energy balance and gut microbiota composition. We compared effects of diets containing high egg or whey protein with cellulose or prebiotic (inulin) fiber on energy balance, gut microbiota, hormones, and metabolites. Male obese rats (n=8/group) were allocated to four diets: Egg albumen+Cellulose (EC), Egg albumen+Inulin (EI), Whey protein+Cellulose (WC), and Whey protein+Inulin (WI). Results revealed that diet-induced hypophagia was transient with EC and prolonged with EI and WI, compared to WC. Importantly, CCK-1 receptor antagonist (Devazepide) attenuated the hypophagic effects of EC, EI, and WI. Further, EC, EI and WI decreased respiratory quotient, energy expenditure, weight and adiposity gains, and improved glycemia, relative to WC. Propranolol (ß1-ß2-receptor blocker) attenuated diet-induced changes in energy expenditure. Transcript abundance of thermogenic markers in brown adipose tissue, plasma hormones, and metabolites especially acyl-carnitines and glycerophospholipids, were differentially altered by diets. Diet explained 25% of compositional differences in cecal microbiomes, but diets with same fiber type did not differ. Microbiota differing between groups also strongly correlated with gut hormones and metabolites. Species most strongly correlated to a marker for butyrate production were in highest abundance in inulin diets. Together, these findings indicate that inulin enriched diets containing egg or whey protein improved energy balance, decreased adiposity, and modulated gut microbiota and metabolites, with CCK signaling partly mediating the satiety effects of diets.

Microorganism Profiles of Penile Prosthesis Removed for Infection, Erosion, and Mechanical Malfunction Based on Next-Generation Sequencing.

BACKGROUND: Next-generation sequencing (NGS) is an emerging technology that may allow for more sensitive and sophisticated microbial testing of the microbiota of penile prostheses (PP). AIM: To describe the microorganism profiles of PP explanted for infection, erosion, and mechanical malfunction using NGS. METHODS: All patients who underwent PP removal by two physicians at two institutions were identified. Differences in alpha diversity (ie, number of species detected, species diversity across samples) and microbiome compositional profiles (Bray-Curtis community dissimilarities) across samples were assessed using ANOVA and PERMANOVA, respectively. OUTCOMES: Number of species detected, species diversity across samples, and microbiome compositional profiles. RESULTS: A total of 83 patients who underwent device removal for infection (n = 8, 10%), erosion (n = 5, 6%), and mechanical malfunction (n = 70, 84%) were included. When considering all devices, 56% (n = 48) of NGS and 29% (n = 24) of standard cultures resulted positive for presence of microorganisms. Culture only detected the most abundant NGS species in 62.5% (n = 5) of infected devices. Species richness and microbiome compositional profiles varied by surgical indication, but not by age, race, diabetes status, or implant duration. Most frequent organisms by surgical indication were Pseudomonas aeruginosa (infection), Staphylococcus epidermidis (erosion), and Escherichia coli (mechanical malfunction). The highest relative abundance organisms were P aeruginosa (infection), Corynebacterium jeikeium (erosion), and E coli (mechanical malfunction). CLINICAL IMPLICATIONS: Identifying microbiome profiles of PP removed for infection, erosion, and mechanical malfunction may guide the selection of peri-operative antibiotics and PP antibiotic coatings or hydrophilic dip solutions for each individual scenario. STRENGTHS AND LIMITATIONS: While this is the first study to utilize next-generation sequencing to evaluate penile prosthesis biofilm, the clinical significance of these findings has yet to be determined. A prospective, randomized trial aimed at evaluating the clinical significance of NGS in patients with PP infection is currently underway. CONCLUSION: NGS testing identified distinct microbiome profiles of PP removed for infection, erosion, and mechanical malfunction. Chung PH, Leong JY, Phillips CD, Henry GD. Microorganism Profiles of Penile Prosthesis Removed for Infection, Erosion, and Mechanical Malfunction Based on Next-Generation Sequencing. J Sex Med 2022;19:356-363.

Positive Selection and Gene Expression Analyses from Salivary Glands Reveal Discrete Adaptations within the Ecologically Diverse Bat Family Phyllostomidae.

The leaf-nosed bats (Phyllostomidae) are outliers among chiropterans with respect to the unusually high diversity of dietary strategies within the family. Salivary glands, owing to their functions and high ultrastructural variability among lineages, are proposed to have played an important role during the phyllostomid radiation. To identify genes underlying salivary gland functional diversification, we sequenced submandibular gland transcriptomes from phyllostomid species representative of divergent dietary strategies. From the assembled transcriptomes, we performed an array of selection tests and gene expression analyses to identify signatures of adaptation. Overall, we identified an enrichment of immunity-related gene ontology terms among 53 genes evolving under positive selection. Lineage-specific selection tests revealed several endomembrane system genes under selection in the vampire bat. Many genes that respond to insulin were under selection and differentially expressed genes pointed to modifications of amino acid synthesis pathways in plant-visitors. Results indicate salivary glands have diversified in various ways across a functional diverse clade of mammals in response to niche specializations.

Patient genetics is linked to chronic wound microbiome composition and healing.

The clinical importance of microbiomes to the chronicity of wounds is widely appreciated, yet little is understood about patient-specific processes shaping wound microbiome composition. Here, a two-cohort microbiome-genome wide association study is presented through which patient genomic loci associated with chronic wound microbiome diversity were identified. Further investigation revealed that alternative TLN2 and ZNF521 genotypes explained significant inter-patient variation in relative abundance of two key pathogens, Pseudomonas aeruginosa and Staphylococcus epidermidis. Wound diversity was lowest in Pseudomonas aeruginosa infected wounds, and decreasing wound diversity had a significant negative linear relationship with healing rate. In addition to microbiome characteristics, age, diabetic status, and genetic ancestry all significantly influenced healing. Using structural equation modeling to identify common variance among SNPs, six loci were sufficient to explain 53% of variation in wound microbiome diversity, which was a 10% increase over traditional multiple regression. Focusing on TLN2, genotype at rs8031916 explained expression differences of alternative transcripts that differ in inclusion of important focal adhesion binding domains. Such differences are hypothesized to relate to wound microbiomes and healing through effects on bacterial exploitation of focal adhesions and/or cellular migration. Related, other associated loci were functionally enriched, often with roles in cytoskeletal dynamics. This study, being the first to identify patient genetic determinants for wound microbiomes and healing, implicates genetic variation determining cellular adhesion phenotypes as important drivers of infection type. The identification of predictive biomarkers for chronic wound microbiomes may serve as risk factors and guide treatment by informing patient-specific tendencies of infection.

Differential Expression in Testis and Liver Transcriptomes from Four Species of Peromyscus (Rodentia: Cricetidae).

The genus Peromyscus represents a rapidly diverged clade of Cricetid rodents that contains multiple cryptic species and has a propensity for morphologic conservation across its members. The unresolved relationships in previously proposed phylogenies reflect a suspected rapid adaptive radiation. To identify functional groups of genes that may be important in reproductive isolation in a reoccurring fashion across the Peromyscus phylogeny, liver and testis transcriptomes from four species (P. attwateri, P. boylii, P. leucopus, and P. maniculatus) were generated and differential expression (DE) tests were conducted. Taxa were selected to represent members diverged from a common ancestor: P. attwateri + P. boylii (clade A), and P. leucopus + P. maniculatus (clade B). Comparison of clades (A vs. B) suggested that 252 transcripts had significant DE in the liver data set, whereas significant DE was identified for 657 transcripts in the testis data set. Further, 45 genes had DE isoforms in the 657 testis transcripts and most of these functioned in major reproductive roles such as acrosome assembly, spermatogenesis, and cell cycle processes (meiosis). DE transcripts in the liver mapped to more broad gene ontology terms (metabolic processes, catabolic processes, response to chemical, and regulatory processes), and DE transcripts in the testis mapped to gene ontology terms associated with reproductive processes, such as meiosis, sperm motility, acrosome assembly, and sperm-egg fusion. These results suggest that a suite of genes that conduct similar functions in the testes may be responsible for the adaptive radiation events and potential reoccurring speciation of Peromyscus in terms of reproduction through varying expression levels.

Chronic wound microbiome colonization on mouse model following cryogenic preservation.

Chronic wound infections are increasingly recognized to be dynamic and polymicrobial in nature, necessitating the development of wound models which reflect the complexities of infection in a non-healing wound. Wound slough isolated from human chronic wounds and transferred to mice was recently shown to create polymicrobial infection in mice, and there is potential this tool may be improved by cryogenic preservation. The purpose of this study was to investigate the application of cryogenic preservation to transferring polymicrobial communities, specifically by quantifying the effects of cryopreservation and wound microbiome transplantation. Slough from an established murine polymicrobial surgical excision model and five patients were subjected to three preservation strategies: refrigeration until infection, freezing in liquid nitrogen, or freezing in liquid nitrogen with glycerol solution prior to infection in individual mice. Four days following inoculation onto mice, wound microbiota were quantified using either culture isolation or by 16s rRNA gene community profiling and quantitative PCR. Cryogenic preservation did not significantly reduce bacterial viability. Reestablished microbial communities were significantly associated with patient of origin as well as host context (i.e., originally preserved from a patient versus mouse infection). Whereas preservation treatment did not significantly shape community composition, the transfers of microbiomes from human to mouse were characterized by reduced diversity and compositional changes. These findings indicated that changes should be expected to occur to community structure after colonization, and that compositional change is likely due to the rapid change in infection context as opposed to preservation strategy. Furthermore, species that were present in higher relative abundance in wound inoculate were more likely to colonize subsequent wounds, and wound inoculate with higher bacterial load established wound communities that were more compositionally similar. Results inform expectations for the complementation of chronic wound in vivo modeling with cryogenic preservation archives.

Metagenomic sequencing provides insights into microbial detoxification in the guts of small mammalian herbivores (Neotoma spp.).

Microbial detoxification of plant toxins influences the use of plants as food sources by herbivores. Stephen's woodrats (Neotoma stephensi) specialize on juniper, which is defended by oxalate, phenolics and monoterpenes, while closely related N. albigula specialize on cactus, which only contains oxalate. Woodrats maintain two gut chambers harboring dense microbial communities: a foregut chamber proximal to the major site of toxin absorption, and a cecal chamber in their hindgut. We performed several experiments to investigate the location and nature of microbial detoxification in the woodrat gut. First, we measured toxin concentrations across gut chambers of N. stephensi. Compared to food material, oxalate concentrations were immediately lower in the foregut, while concentrations of terpenes remained high in the foregut, and were lowest in the cecal chamber. We conducted metagenomic sequencing of the foregut chambers of both woodrat species and cecal chambers of N. stephensi to compare microbial functions. We found that most genes associated with detoxification were more abundant in the cecal chambers of N. stephensi. However, some genes associated with degradation of oxalate and phenolic compounds were more abundant in the foregut chambers. Thus, microbial detoxification may take place in various chambers depending on the class of chemical compound.

Elevated mitochondrial genome variation after 50 generations of radiation exposure in a wild rodent.

Currently, the effects of chronic, continuous low dose environmental irradiation on the mitochondrial genome of resident small mammals are unknown. Using the bank vole (Myodes glareolus) as a model system, we tested the hypothesis that approximately 50 generations of exposure to the Chernobyl environment has significantly altered genetic diversity of the mitochondrial genome. Using deep sequencing, we compared mitochondrial genomes from 131 individuals from reference sites with radioactive contamination comparable to that present in northern Ukraine before the 26 April 1986 meltdown, to populations where substantial fallout was deposited following the nuclear accident. Population genetic variables revealed significant differences among populations from contaminated and uncontaminated localities. Therefore, we rejected the null hypothesis of no significant genetic effect from 50 generations of exposure to the environment created by the Chernobyl meltdown. Samples from contaminated localities exhibited significantly higher numbers of haplotypes and polymorphic loci, elevated genetic diversity, and a significantly higher average number of substitutions per site across mitochondrial gene regions. Observed genetic variation was dominated by synonymous mutations, which may indicate a history of purify selection against nonsynonymous or insertion/deletion mutations. These significant differences were not attributable to sample size artifacts. The observed increase in mitochondrial genomic diversity in voles from radioactive sites is consistent with the possibility that chronic, continuous irradiation resulting from the Chernobyl disaster has produced an accelerated mutation rate in this species over the last 25 years. Our results, being the first to demonstrate this phenomenon in a wild mammalian species, are important for understanding genetic consequences of exposure to low-dose radiation sources.

Microbiome Structural and Functional Interactions across Host Dietary Niche Space.

Host-associated microbiomes are integral components of host health, but microbiome community structure varies among and within hosts. Reconciling community variability with the apparent dependence of hosts on community function, and characterizing how functional divergence proceeds across niches, remains challenging. Here, through the study of gut microbiomes and diets of three insectivorous bat species we characterize how community structure is shaped by predicted functional properties of community members. We found that while host diet and microbiome community composition do not significantly relate to each other, host diet and metagenome function do, suggesting that diet directly selects metagenomic functions rather than communities. We use a novel inference framework to show how the discordance between community structure and functional variation derives from functional equivalence and is influenced by the continuum of shared and derived gene sets across microbial lineages. Our findings help clarify how metagenome community structure-function relationships contribute to deterministic processes in community assembly, and describe the basis for metagenomic differences across ecologically similar hosts.

Temporal dynamics of relative abundances and bacterial succession in chronic wound communities.

Polymicrobial bacterial infection is an important factor contributing to wound chronicity. Consequently, clinicians frequently adopt a biofilm-based wound care approach, in which wounds are treated utilizing DNA sequencing information about microbial communities. While more successful than treatment not using community information, there is little information about temporal dynamics of wound communities and optimal approaches over the course of treatment. To characterize these dynamics, temporal analysis over three sampling points was conducted for 167 chronic wounds. Across sampling intervals, wound communities from the same patients changed in composition, and most commonly shared less than 50% of observed species. There was a significant relationship between community similarity and time between sampling. Classifying wounds into state types, we found that communities frequently transitioned from Pseudomonas or Staphylococcus dominated, into a highly variable state type. Although low abundance microbial species are typically disregarded due to uncertainty of biological importance, we found that 80% of wound microbiomes included common or dominant species at subsequent time points that were in low abundance in earlier samples. Moreover, these species were often those known to frequently infect wounds. Results document compositional shifts through the course of treatment and suggest that routine consideration of low abundance species may improve biofilm-based wound care. Moreover, findings indicate that integrating ecological modeling to understand wound microbiome succession may lead to more informed therapy.

Respiratory viral detection in the paranasal sinuses of patients with cystic fibrosis.

BACKGROUND: Pulmonary colonization with antibiotic-resistant organisms in patients with cystic fibrosis (CF) is often preceded by upper-airway infections. Although there is a well-described relationship between pulmonary respiratory viral infections and overall disease progression of CF, the pathogenicity of respiratory viral infections in the paranasal sinuses of patients with CF remains unknown. With recent advances in respiratory virus detection techniques, this study sought to detect the presence of respiratory viruses in the paranasal sinuses of patients with CF in comparison with healthy controls and to correlate the viral presence with clinical measures of sinonasal disease. METHODS: This prospective individual cohort study compared 24 patients with CF with 14 healthy controls. Basic demographics, clinical measures of disease and respiratory viral screens (commercial multiplex) obtained directly from the paranasal sinuses were compared between the two groups. RESULTS: Respiratory viruses were detected in 33% of patients with CF (8/24) compared with 0% of the healthy controls (0/14) (p = 0.017). Respiratory viruses were only detected during the winter months, and the most commonly identified were influenza A and human rhinovirus strains. There was no statistical difference in the 22-Item Sino-Nasal Outcome Test (SNOT-22) scores (p = 0.93) or modified Lund-Kennedy scores (p = 0.74) between patients with CF with a positive viral test and those without a positive result. CONCLUSIONS: Respiratory viral detection is more commonly detected in the paranasal sinuses of patients with CF compared with healthy controls. Although respiratory viral presence did not correlate with a worse clinical severity of sinonasal disease, these findings may provide insight into the pathophysiology of CF and open new avenues for potential targeted therapy.

Analysis of the Duodenal Microbiome in Autistic Individuals: Association With Carbohydrate Digestion.

OBJECTIVES: There is evidence that symptoms of maldigestion or malabsorption in autistic individuals are related to changes in the indigenous microbiota. Analysis of colonic bacteria has revealed microbial dysbiosis in children with autism; however, characteristics of the duodenal microbiome are not well described. In the present study the microbiome of the duodenal mucosa of subjects with autism was evaluated for dysbiosis, bacteria overgrowth, and microbiota associated with carbohydrate digestion. The relationship between the duodenal microbiome and disaccharidase activity was analyzed in biopsies from 21 autistic subjects and 19 children without autism. METHODS: Microbiota composition was determined by 16S ribosomal RNA gene sequencing, and disaccharidase activity via biochemical assays. RESULTS: Although subjects with autism had a higher frequency of constipation (P < 0.005), there was no difference in disaccharidase activity between groups. In addition, no differences in microbiome diversity (species richness and evenness) were observed. Bacteria belonging to the genus Burkholderia were more abundant in subjects with autism, whereas members of the genus Neisseria were less abundant. At the species level, a relative decrease in abundance of 2 Bacteroides species and Escherichia coli was found in autistic individuals. There was a positive correlation between the abundance of Clostridium species, and disaccharidase activity, in autistic individuals. CONCLUSIONS: There are a variety of changes at the genus and species level in duodenal microbiota in children with autism that could be influenced by carbohydrate malabsorption. These observations could be affected by variations in individual diets, but also may represent a more pervasive dysbiosis that results in metabolites that affect the behavior of autistic children.

Antibiotic Treatment Induces Long-lasting Changes in the Fecal Microbiota that Protect Against Colitis.

BACKGROUND: The interplay between host genetics, immunity, and microbiota is central to the pathogenesis of inflammatory bowel disease. Previous population-based studies suggested a link between antibiotic use and increased inflammatory bowel disease risk, but the mechanisms are unknown. The purpose of this study was to determine the long-term effects of antibiotic administration on microbiota composition, innate immunity, and susceptibility to colitis, as well as the mechanism by which antibiotics alter host colitogenicity. METHODS: Wild-type mice were given broad-spectrum antibiotics or no antibiotics for 2 weeks, and subsequent immunophenotyping and 16S rRNA gene sequencing-based analysis of the fecal microbiome were performed 6 weeks later. In a separate experiment, control and antibiotic-treated mice were given 7 days of dextran sulfate sodium, 6 weeks after completing antibiotic treatment, and the severity of colitis scored histologically. Fecal transfer was performed from control or antibiotic-treated mice to recipient mice whose endogenous microbiota had been cleared with antibiotics, and the susceptibility of the recipients to dextran sulfate sodium-induced colitis was analyzed. Naive CD4 T cells were transferred from control and antibiotic-treated mice to immunodeficient Rag-1 recipients and the severity of colitis compared. RESULTS: Antibiotics led to sustained dysbiosis and changes in T-cell subpopulations, including reductions in colonic lamina propria total T cells and CD4 T cells. Antibiotics conferred protection against dextran sulfate sodium colitis, and this effect was transferable by fecal transplant but not by naive T cells. CONCLUSIONS: Antibiotic exposure protects against colitis, and this effect is transferable with fecal microbiota from antibiotic-treated mice, supporting a protective effect of the microbial community.

Human-modified habitats change patterns of population genetic structure and group relatedness in Peter's tent-roosting bats.

Although coloniality is widespread among mammals, it is still not clear what factors influence composition of social groups. As animals need to adapt to multiple habitat and environmental conditions throughout their range, variation in group composition should be influenced by adaptive adjustment to different ecological factors. Relevant to anthropogenic disturbance, increased habitat modification by humans can alter species' presence, density, and population structure. Therefore, it is important to understand the consequences of changes to landscape composition, in particular how habitat modification affects social structure of group-forming organisms. Here, we combine information on roosting associations with genetic structure of Peter's tent-roosting bats, Uroderma bilobatum to address how different habitat characteristics at different scales affect structure of social groups. By dividing analyses by age and sex, we determined that genetic structure was greater for adult females than adult males or offspring. Habitat variables explained 80% of the variation in group relatedness (mainly influenced by female relatedness) with roost characteristics contributing the most explained variation. This suggests that females using roosts of specific characteristics exhibit higher relatedness and seem to be philopatric. These females mate with more males than do more labile female groups. Results describe ecological and microevolutionary processes, which affect relatedness and social structure; findings are highly relevant to species distributions in both natural and human-modified environments.

Analysis of the chronic wound microbiota of 2,963 patients by 16S rDNA pyrosequencing.

The extent to which microorganisms impair wound healing is an ongoing controversy in the management of chronic wounds. Because the high diversity and extreme variability of the microbiota between individual chronic wounds lead to inconsistent findings in small cohort studies, evaluation of a large number of chronic wounds using identical sequencing and bioinformatics methods is necessary for clinicians to be able to select appropriate empiric therapies. In this study, we utilized 16S rDNA pyrosequencing to analyze the composition of the bacterial communities present in samples obtained from patients with chronic diabetic foot ulcers (N = 910), venous leg ulcers (N = 916), decubitus ulcers (N = 767), and nonhealing surgical wounds (N = 370). The wound samples contained a high proportion of Staphylococcus and Pseudomonas species in 63 and 25% of all wounds, respectively; however, a high prevalence of anaerobic bacteria and bacteria traditionally considered commensalistic was also observed. Our results suggest that neither patient demographics nor wound type influenced the bacterial composition of the chronic wound microbiome. Collectively, these findings indicate that empiric antibiotic selection need not be based on nor altered for wound type. Furthermore, the results provide a much clearer understanding of chronic wound microbiota in general; clinical application of this new knowledge over time may help in its translation to improved wound healing outcomes.

The role of viruses in the clinical presentation of chronic rhinosinusitis.

BACKGROUND: The role of viruses in chronic rhinosinusitis (CRS) is poorly understood. In part, this is secondary to difficulty in isolating viruses. Although traditional detection methods for respiratory viruses have had little clinical utility, modern viral screening techniques that use molecular sequencing are now both rapid and feasible, which makes analysis of the paranasal sinus microbiome more accessible. OBJECTIVE: To detect respiratory viruses in the paranasal sinuses of patients with CRS and of healthy controls as well as to correlate clinical and radiographic measures of CRS with viral presence. METHODS: In this prospective study, 13 patients with CRS with nasal polyposis (CRSwNP) and 8 patients without nasal polyposis (CRSsNP) were enrolled and compared with 14 healthy controls. Samples were obtained from the paranasal sinuses and were screened for viral DNA with polymerase chain reaction--based sequencing techniques. Typical symptoms of CRS, the Sinonasal Questionnaire, and objective measures, including the modified Lund-Mackay and modified Lund-Kennedy scores were obtained. RESULTS: Eighty percent of the positive screens (4/5) were found in patients with CRSsNP, whereas 20% of the positive tests (1/5) were in the CRSwNP group, and none of the controls tested positive (p = 0.0029). Coronavirus was the most common virus detected. Sinonasal Questionnaire scores of the patients with CRS who tested positive for viruses were higher but not statistically different than those without a positive screen (p = 0.31). Radiographic and endoscopic measures of disease were not significantly different in the setting of a positive viral screen (p = 0.12 and 0.11 respectively). CONCLUSION: Although traditionally difficult, advances in molecular sequencing enhance detection of viruses in the sinonasal tract. In this study, respiratory viruses were more commonly isolated from patients with CRS compared with healthy controls. Moreover, viral infection may play a greater role in symptom exacerbation in CRSsNP than in CRSwNP. These findings warrant further investigation into the role of the viral microbiome in CRS.