Diane S. Hutchinson

Altered Mucosal Microbiome Diversity and Disease Severity in Sjögren Syndrome.

There is mounting evidence that the microbiome has potent immunoregulatory functions. We assessed the effects of intestinal dysbiosis in a model of Sjögren syndrome (SS) by subjecting mice to desiccating stress (DS) and antibiotics (ABX). We characterized the conjunctival, tongue and fecal microbiome profiles of patients with SS. Severity of ocular surface and systemic disease was graded. 16S ribosomal RNA gene sequencing characterized the microbiota. ABX + DS mice had a significantly worse dry eye phenotype compared to controls, a decrease in Clostridium and an increase in Enterobacter, Escherichia/Shigella, and Pseudomonas in stool after ABX + DS for 10 days. Goblet cell density was significantly lower in ABX treated groups compared to controls. Stool from SS subjects had greater relative abundances of Pseudobutyrivibrio, Escherichia/Shigella, Blautia, and Streptococcus, while relative abundance of Bacteroides, Parabacteroides, Faecalibacterium, and Prevotella was reduced compared to controls. The severity of SS ocular and systemic disease was inversely correlated with microbial diversity. These findings suggest that SS is marked by a dysbiotic intestinal microbiome driven by low relative abundance of commensal bacteria and high relative abundance of potentially pathogenic genera that is associated with worse ocular mucosal disease in a mouse model of SS and in SS patients.

Genetic and Environmental Determinants of Otitis Media in an Indigenous Filipino Population

Objective To identify genetic and environmental risk factors for otitis media in an indigenous Filipino population. Study Design Cross-sectional study. Setting Indigenous Filipino community. Subjects and Methods Clinical history and information on breastfeeding, tobacco smoke exposure, and swimming were obtained from community members. Heads of households were interviewed for family history and personal beliefs on ear health. Height and weight were measured. Otoscopic findings were described for the presence and character of perforation or discharge. An A2ML1 duplication variant that confers otitis media susceptibility was Sanger sequenced in all DNA samples. Co-occurrence of middle ear bacteria detected by 16S rRNA gene sequencing was determined according to A2ML1 genotype and social cluster. Results The indigenous Filipino population has a ~50% prevalence of otitis media. Young age was associated with otitis media (4 age strata; P = .004); however, age was nonsignificant as a bistratal or continuous variable. There was no association between otitis media and sex, body mass index, breastfeeding, tobacco exposure, or deep swimming. In multivariate analyses, A2ML1 genotype is the strongest predictor of otitis media, with an odds ratio of 3.7 (95% confidence interval: 1.3-10.8; P = .005). When otitis media diagnoses were plotted across ages, otitis media was observed within the first year of life, and chronic otitis media persisted up to adulthood, particularly in A2ML1-variant carriers. Conclusion Among indigenous Filipinos, A2ML1 genotype is the primary risk factor for otitis media and main determinant of disease progression, although age, the middle ear microbiome, and social clusters might modulate the effect of the A2ML1 genotype.

Impact of environmental microbiota on human microbiota of workers in academic mouse research facilities: An observational study

Objectives To characterize the microbial environment of workers in academic mouse research facilities using endotoxin, 16S qPCR, and 16S amplicon sequencing. To determine whether the work microbiome contributes to the human microbiome of workers. Methods We performed area air sampling from the animal rooms, dirty, middle, and setup cage wash locations in four academic mouse research facilities. 10 workers in the dirty cage wash area underwent personal air sampling as well as repeated collection of nasal, oral, and skin samples before and after the work shift. Environmental samples underwent measurement of endotoxin, mouse allergen, bacteria copy number via 16S qPCR, and microbial identification via 16S rDNA sequencing. 16S rDNA sequencing was also performed on human samples before and after the work shift. SourceTracker was used to identify the contribution of the work microbiome to the human microbiome. Results Median endotoxin levels ranged from undetectable to 1.0 EU/m3. Significant differences in mouse allergen levels, bacterial copy number, microbial richness, and microbial community structure were identified between animal, dirty, middle, and setup cage wash locations. Endotoxin levels had only a moderate correlation with microbial composition. Location within a facility was a stronger predictor of microbial community composition (R2 = 0.41, p = 0.002) than facility. The contribution of the work microbiome to the pre-shift human microbiome of workers was estimated to be 0.1 ± 0.1% for the oral microbiome; 3.1 ± 1.9% for the nasal microbiome; and 3.0 ± 1.5% for the skin microbiome. Conclusions The microbial environment of academic animal care facilities varies significantly by location rather than facility. Endotoxin is not a proxy for assessment of environmental microbial exposures using 16S qPCR or 16S rDNA sequencing. The work microbiome contributes to the composition of the nasal and skin microbiome of workers; the clinical implications of this observation should be further studied.

Abstract 2672: Response to anti-PD-1 based therapy in metastatic melanoma patients is associated with the diversity and composition of the gut microbiome

Background: Melanoma therapy has benefitted greatly from immune checkpoint blockade, although responses are variable and not always durable. There is a growing appreciation of the role of the microbiome in cancer-related outcomes and recent evidence in murine models suggests that modulation of the gut microbiome may enhance responses to immune checkpoint blockade in melanoma. However this has not been investigated in patients. Here, we demonstrate that differential bacterial “signatures” exist in the gut microbiome of responders (R) and non-responders (NR) to anti-PD-1 therapy, and that insights gained could be used to derive actionable strategies to enhance responses. Methods: We collected buccal (n=105) and stool (n=53) samples from a cohort of anti-PD-1 treated metastatic melanoma patients (n=110). Patients were classified as either R or NR based on RECIST criteria, and 16S rDNA, and whole-genome shotgun sequencing was performed to characterize the diversity, composition and functional capabilities of the microbiomes. Immune profiling (via 7-marker IHC panel of CD3, CD8, PD-1, PD-L1, Granzyme B, RORγT and FoxP3) and cytokine analyses were also performed on available tumors and serum samples at baseline. Results: In these studies, we observed significant differences in the diversity and composition of the gut microbiome in R versus NR to PD-1 blockade at baseline, but no clear differences in buccal microbiomes. Specifically, R had a significantly higher alpha diversity compared to NR (p=0.017), and the Ruminococcaceae family of the Clostridiales order was enriched in R whereas Prevotellaceae family of the Bacteroidales order was enriched in NR. Immune profiling demonstrated significantly increased immune infiltrates in baseline tumor samples of R, with a positive correlation between CD8, CD3, PD-1 and FoxP3 T-cell density and abundance of specific bacteria enriched in R (e.g. Faecalibacterium). Low diversity was also associated with elevated levels of chronic inflammation markers in the serum at baseline. Lastly, we saw differentially abundant metabolic pathways in the gut microbiomes of R (pyrimidine nucleotide biosynthesis, fatty acid biosynthesis, shikimate pathway) vs NR (Tricarboxylic acid cycle, assimilatory sulphate and nitrate reduction, tryptophan biosynthesis). Conclusion: Differences exist in the diversity and composition of the gut microbiome in R vs NR to anti-PD-1 therapy and these microbiota could bridge the gap between host metabolism and anti-tumor immunity. These results have far-reaching implications and suggest that modifications to the gut microbiome could potentially enhance therapeutic responses to immune checkpoint blockade. Citation Format: Vancheswaran Gopalakrishnan, Christine Spencer, Alexandre Reuben, Peter Prieto, Diego Vicente, Tatiana V. Karpinets, Courtney W. Hudgens, Diane S. Hutchinson, Michael Tetzlaff, Alexander Lazar, Michael A. Davies, Jeffrey E. Gershenwald, Robert Jenq, Patrick Hwu, Padmanee Sharma, James Allison, Andrew Futreal, Nadim Ajami, Joseph Petrosino, Carrie Daniel-MacDougall, Jennifer A. Wargo. Response to anti-PD-1 based therapy in metastatic melanoma patients is associated with the diversity and composition of the gut microbiome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2672. doi:10.1158/1538-7445.AM2017-2672

Middle ear microbiome differences in indigenous Filipinos with chronic otitis media due to a duplication in the A2ML1 gene.

BackgroundPreviously rare A2ML1 variants were identified to confer otitis media susceptibility in an indigenous Filipino community and in otitis-prone US children. The goal of this study is to describe differences in the middle ear microbiome between carriers and non-carriers of an A2ML1 duplication variant that increases risk for chronic otitis media among indigenous Filipinos with poor health care access.MethodsEar swabs were obtained from 16 indigenous Filipino individuals with chronic otitis media, of whom 11 carry the A2ML1 duplication variant. Ear swabs were submitted for 16S rRNA gene sequencing.ResultsGenotype-based differences in microbial richness, structure, and composition were identified, but were not statistically significant. Taxonomic analysis revealed that the relative abundance of the phyla Fusobacteria and Bacteroidetes, and genus Fusobacterium were nominally increased in carriers compared to non-carriers, but were non-significant after correction for multiple testing. We also detected rare bacteria including Oligella that was reported only once in the middle ear.ConclusionsThese findings suggest that A2ML1-related otitis media susceptibility may be mediated by changes in the middle ear microbiome. Knowledge of middle ear microbial profiles according to genetic background can be potentially useful for therapeutic and prophylactic interventions for otitis media and can guide public health interventions towards decreasing otitis media prevalence within the indigenous Filipino community.

Conjunctival Microbiome Changes Associated With Soft Contact Lens and Orthokeratology Lens Wearing.

Purpose Usage of different types of contact lenses is associated with increased risk of sight-threatening complications. Changes in the ocular microbiome caused by contact lens wear are suggested to affect infection development in those individuals. To address this question, this study compares conjunctival microbial communities in contact lens wearers with those in noncontact lens wearers. Methods Paired-end sequencing of the V3 region of the 16S rRNA gene was used to characterize the bacterial communities on the conjunctival surfaces of contact lens wearers and nonwearers. Results No differences in microbial diversity were detected between contact lens wearers and nonwearers. Nevertheless, some slight microbe variability was evident between these two different groups. Bacillus, Tatumella and Lactobacillus abundance was less in orthokeratology lens (OKL) wearers than in nonwearers. In soft contact lenses (SCL) wearers, Delftia abundance decreased whereas Elizabethkingia levels increased. The difference in the SCL and nonwearer group was smaller than that in the OKL group. Variations in the conjunctival taxonomic composition between SCL wearers were larger than those in other groups. Sex differences in the conjunctival microbiota makeup were only evident among nonwearers. Conclusions Even though there were slight percentage changes between contact lens wearers and nonwearers in some microbes, there were no differences in their diversity. On the other hand, contact lens usage might cause relative abundance of some taxa to change. Our results will help assess whether or not conjunctival microbiome changes caused by contact lens wear affect infection risk.

Oral microbiota reveals signs of acculturation in Mexican American women

The oral microbiome has been linked to a number of chronic inflammatory conditions, including obesity, diabetes, periodontitis, and cancers of the stomach and liver. These conditions disproportionately affect Mexican American women, yet few studies have examined the oral microbiota in this at-risk group. We characterized the 16S rDNA oral microbiome in 369 non-smoking women enrolled in the MD Anderson Mano a Mano Mexican American Cohort Study. Lower bacterial diversity, a potential indicator of oral health, was associated with increased age and length of US residency among recent immigrants. Grouping women by overarching bacterial community type (e.g., “Streptococcus,” “Fusobacterium,” and “Prevotella” clusters), we observed differences across a number of acculturation-related variables, including nativity, age at immigration, time in the US, country of longest residence, and a multi-dimensional acculturation scale. Participants in the cluster typified by higher abundance of Streptococcus spp. exhibited the lowest bacterial diversity and appeared the most acculturated as compared to women in the “Prevotella” group. Computationally-predicted functional analysis suggested the Streptococcus-dominated bacterial community had greater potential for carbohydrate metabolism while biosynthesis of essential amino acids and nitrogen metabolism prevailed among the Prevotella-high group. Findings suggest immigration and adaption to life in the US, a well-established mediator of disease risk, is associated with differences in oral microbial profiles in Mexican American women. These results warrant further investigation into the joint and modifying effects of acculturation and oral bacteria on the health of Mexican American women and other immigrant populations. The oral microbiome presents an easily accessible biomarker of disease risk, spanning biological, behavioral, and environmental factors.

Opinion Paper: Promise and Pragmatism in Clinical Microbiome Research

The evolution of human microbiome research has lead to a systems biology approach that encompasses multidisciplinary investigations. The implementation of next generation sequencing technologies has allowed researchers to study unculturable organisms, discover novel ones, and provide insights into the role of the human microbiome in health and disease. When these approaches are applied to large-scale longitudinal studies designed to interrogate the association of the microbiome with specific clinical outcomes, the development of new therapeutics and diagnostics intended to modulate or detect changes in microbiome composition to improve human health are born. We are just starting to unravel the role of the microbiome in a wide-variety of diseases, and while some of it appears to be related to causation and provide opportunities for intervention, a good dose of pragmatism is warranted as the field is still in its infancy.