Antimicrobial susceptibilities and clinical sources of Dialister species

Urine microbes and predictive metagenomic profiles associate with abnormalities in sperm parameters: implications for male subfertility

OBJECTIVE

To explore the taxonomic and predicted functional relationship between the urine microbiome and alterations of semen analysis (SA) parameters.

DESIGN

Cross-sectional study.

SETTING

Academic medical center.

PATIENT(S)

Men presenting for fertility evaluation or men presenting for vasectomy consultation with proven biological paternity were recruited and stratified on the basis of alterations, or lack thereof, in SA parameters.

MAIN OUTCOME MEASURE

Changes in the functional and taxonomic urine microbiome profiles of participants with or without alterations in SA parameters.

RESULTS

Seventy-three participants were included in our study. Men with abnormal sperm motility (N = 27) showed a nearly 50-fold higher abundance of Dialister micraerophilus compared with those with normal sperm motility (N = 46). This relationship persisted on canonical correlational analysis (r = 0.439). Men with abnormal sperm concentration (N = 20) showed a lower abundance of Enterococcus faecalis and Staphylococcus aureus, compared with those with normal sperm concentration (N = 53). The urine of participants with impaired sperm motility demonstrated dramatic differences in predictive functional profiles in pathways involved in oxidation-reduction balance and cell longevity.

CONCLUSIONS

Our findings underscore differences in the urinary microbiome and abnormalities in semen parameters, especially sperm motility. By incorporating predictive functional profiling, we also highlight possible mechanisms that may drive the observed differences in sperm parameters.

A case of bacteremia caused by Dialister micraerophilus with Enterocloster clostridioformis and Eggerthella lenta in a patient with pyometra

BACKGROUND

Infection by Dialister micraerophilus, an obligate anaerobic gram-negative bacillus, has rarely been described, and its clinical characteristics remain unclear.

CASE PRESENTATION

We report a case of bacteremia caused by D. micraerophilus, Enterocloster clostridioformis, and Eggerthella lenta in a 47-year-old woman, associated with pyometra. D. micraerophilus was identified using 16S rRNA gene sequencing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. D. micraerophilus was detected by polymerase chain reaction using D. micraerophilus-specific primers and E. clostridioformis and E. lenta was isolated from the drainage pus sample obtained from the pyometra uterus. The patient achieved a cure after abscess drainage and 2-week antibiotic treatment.

CONCLUSIONS

To the best of our knowledge, this is the first report of D. micraerophilus bacteremia. D. micraerophilus may be associated with gynecological infections. Clinicians should consider both oral and gynecological sites when searching to identify the focus of D. micraerophilus infection.

Dialister pneumosintes and aortic graft infection - a case report

BACKGROUND

Dialister pneumosintes is an anaerobic, Gram negative bacillus, found in the human oral cavity and associated with periodontitis. It has also been isolated from gastric mucosa and stool samples. Recent case reports implicate D. pneumosintes in local infection such as dental root canals, sinusitis, Lemierres syndrome and brain abscesses, as well as distal infections of the liver and lung through haematogenous spread.

CASE PRESENTATION

We present a novel case of aortic graft infection and aortoenteric fistula (AEF) in a 75 year old Caucasian male, associated with D. pneumosintes bacteraemia. Microbiological evaluation of septic emboli in the lower limbs revealed other gastrointestinal flora. This suggests either AEF leading to graft infection and subsequent distal emboli and bacteraemia, or a dental origin of infection which seeded to the graft, resulting in AEF and systemic infection. To our knowledge this is the first report of D. pneumosintes associated aortic graft infection. The patient underwent surgical explantation, oversew of the aorta and placement of extra-anatomical bypass graft in conjunction with antimicrobial therapy, making a good recovery with discharge home after a 35-day hospital admission.

CONCLUSION

We report a case of Dialister pneumosintes bacteraemia associated with aortic graft infection. To our knowledge, vascular graft-associated infection with D. pneumosintes has not been reported before.

Microbiome subcommunity learning with logistic-tree normal latent Dirichlet allocation

Mixed-membership (MM) models such as latent Dirichlet allocation (LDA) have been applied to microbiome compositional data to identify latent subcommunities of microbial species. These subcommunities are informative for understanding the biological interplay of microbes and for predicting health outcomes. However, microbiome compositions typically display substantial cross-sample heterogeneities in subcommunity compositions-that is, the variability in the proportions of microbes in shared subcommunities across samples-which is not accounted for in prior analyses. As a result, LDA can produce inference, which is highly sensitive to the specification of the number of subcommunities and often divides a single subcommunity into multiple artificial ones. To address this limitation, we incorporate the logistic-tree normal (LTN) model into LDA to form a new MM model. This model allows cross-sample variation in the composition of each subcommunity around some "centroid" composition that defines the subcommunity. Incorporation of auxiliary Pólya-Gamma variables enables a computationally efficient collapsed blocked Gibbs sampler to carry out Bayesian inference under this model. By accounting for such heterogeneity, our new model restores the robustness of the inference in the specification of the number of subcommunities and allows meaningful subcommunities to be identified.

Dysbiosis of oropharyngeal microbiome and antibiotic resistance in hospitalized COVID-19 patients

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is ongoing and multiple studies have elucidated its pathogenesis, however, the related- microbiome imbalance caused by SARS-CoV-2 is still not clear. In this study, we have comprehensively compared the microbiome composition and associated function alterations in the oropharyngeal swabs of healthy controls and coronavirus disease 2019 (COVID-19) patients with moderate or severe symptoms by metatranscriptomic sequencing. We did observe a reduced microbiome alpha-diversity but significant enrichment of opportunistic microorganisms in patients with COVID-19 compared with healthy controls, and the microbial homeostasis was rebuilt following the recovery of COVID-19 patients. Correspondingly, less functional genes in multiple biological processes and weakened metabolic pathways such as carbohydrate metabolism, energy metabolism were also observed in COVID-19 patients. We only found higher relative abundance of limited genera such as Lachnoanaerobaculum between severe patients and moderate patients while no worthy-noting microbiome diversity and function alteration were observed. Finally, we noticed that the co-occurrence of antibiotic resistance and virulence was closely related to the microbiome alteration caused by SRAS-CoV-2. Overall, our findings demonstrate that microbial dysbiosis may enhance the pathogenesis of SARS-CoV-2 and the antibiotics treatment should be critically considered.

Gut Microbiota Composition Can Predict Colonization by Multidrug-Resistant Bacteria in SARS-CoV-2 Patients in Intensive Care Unit: A Pilot Study

The SARS-CoV-2 infection has increased the number of patients entering Intensive Care Unit (ICU) facilities and antibiotic treatments. Concurrently, the multi-drug resistant bacteria (MDRB) colonization index has risen. Considering that most of these bacteria are derived from gut microbiota, the study of its composition is essential. Additionally, SARS-CoV-2 infection may promote gut dysbiosis, suggesting an effect on microbiota composition. This pilot study aims to determine bacteria biomarkers to predict MDRB colonization risk in SARS-CoV-2 patients in ICUs. Seventeen adult patients with an ICU stay >48 h and who tested positive for SARS-CoV-2 infection were enrolled in this study. Patients were assigned to two groups according to routine MDRB colonization surveillance: non-colonized and colonized. Stool samples were collected when entering ICUs, and microbiota composition was determined through Next Generation Sequencing techniques. Gut microbiota from colonized patients presented significantly lower bacterial diversity compared with non-colonized patients (p < 0.05). Microbiota in colonized subjects showed higher abundance of Anaerococcus, Dialister and Peptoniphilus, while higher levels of Enterococcus, Ochrobactrum and Staphylococcus were found in non-colonized ones. Moreover, LEfSe analysis suggests an initial detection of Dialister propionicifaciens as a biomarker of MDRB colonization risk. This pilot study shows that gut microbiota profile can become a predictor biomarker for MDRB colonization in SARS-CoV-2 patients.

Diagnostic and prognostic potential of the microbiome in ovarian cancer treatment response

Ovarian cancer (OC) is the second most common gynecological malignancy and the fifth leading cause of death due to cancer in women in the United States mainly due to the late-stage diagnosis of this cancer. It is, therefore, critical to identify potential indicators to aid in early detection and diagnosis of this disease. We investigated the microbiome associated with OC and its potential role in detection, progression as well as prognosis of the disease. We identified a distinct OC microbiome with general enrichment of several microbial taxa, including Dialister, Corynebacterium, Prevotella, and Peptoniphilus in the OC cohort in all body sites excluding stool and omentum which were not sampled from the benign cohort. These taxa were, however, depleted in the advanced-stage and high-grade OC patients compared to early-stage and low-grade OC patients suggestive of decrease accumulation in advanced disease and could serve as potential indicators for early detection of OC. Similarly, we also observed the accumulation of these mainly pathogenic taxa in OC patients with adverse treatment outcomes compared to those without events and could also serve as potential indicators for predicting patients' responses to treatment. These findings provide important insights into the potential use of the microbiome as indicators in (1) early detection of and screening for OC and (2) predicting patients' response to treatment. Given the limited number of patients enrolled in the study, these results would need to be further investigated and confirmed in a larger study.

Evaluation of the Potential Protective Effects of Lactobacillus Strains against Helicobacter pylori Infection: A Randomized, Double-Blinded, Placebo-Controlled Trial

BACKGROUND

The beneficial effects of probiotic supplementation standard antibiotic therapies for Helicobacter pylori infection have been verified, but the ability of probiotic monotherapy to eradicate H. pylori remains unclear.

AIM

To evaluate the accuracy and efficacy of specific Lactobacillus strains against H. pylori infection.

METHODS

Seventy-eight patients with H. pylori infection were treated with strain L. crispatus G14-5M (L. crispatus CCFM1118) or L. helveticus M2-09-R02-S146 (L. helveticus CCFM1121) or L. plantarum CCFM8610 at a dose of 2 g twice daily for one month. ¹⁴C-urea breath test, the gastrointestinal symptom rating scale, serum pepsinogen concentrations, and serum cytokine concentrations of patients were measured at baseline and end-of-trial to analyze the effect of the Lactobacillus strains in eradicating H. pylori infection and reducing gastrointestinal discomfort in patients. In addition, the composition and abundance of the intestinal microbiota of patients were also measured at end-of-trial.

RESULTS

The ¹⁴C-urea breath test value of the three Lactobacillus treatment groups had decreased significantly, and the eradication rate of H. pylori had increased by the end of the trial. In particular, the eradication rate in the G14-5M treatment group was significantly higher than the placebo group (70.59% vs. 15.38%, P=0.0039), indicating that one-month administration of the G14-5M regimen was sufficient to eradicate H. pylori infection. The ingestion of Lactobacillus strains also ameliorated the gastrointestinal symptom rating scale scores, and the serum interleukin-8 concentrations of H. pylori-infected patients appeared to modulate the gut microbiota of patients. However, none of the Lactobacillus strains had a significant effect on general blood physiological characteristics, serum tumor necrosis factor α concentrations, or serum pepsinogen concentrations in the patients.

CONCLUSION

Three Lactobacillus strains significantly alleviate the gastrointestinal discomfort and the gastric inflammatory response of H. pylori-infected patients. The activity of probiotics in eradicating H. pyloriinfection may be species/strain specific.

Maternal gut microbiota during pregnancy and the composition of immune cells in infancy

Background

Preclinical studies have shown that maternal gut microbiota during pregnancy play a key role in prenatal immune development but the relevance of these findings to humans is unknown. The aim of this prebirth cohort study was to investigate the association between the maternal gut microbiota in pregnancy and the composition of the infant’s cord and peripheral blood immune cells over the first year of life.

Methods

The Barwon Infant Study cohort (n=1074 infants) was recruited using an unselected sampling frame. Maternal fecal samples were collected at 36 weeks of pregnancy and flow cytometry was conducted on cord/peripheral blood collected at birth, 6 and 12 months of age. Among a randomly selected sub-cohort with available samples (n=293), maternal gut microbiota was characterized by sequencing the 16S rRNA V4 region. Operational taxonomic units (OTUs) were clustered based on their abundance. Associations between maternal fecal microbiota clusters and infant granulocyte, monocyte and lymphocyte subsets were explored using compositional data analysis. Partial least squares (PLS) and regression models were used to investigate the relationships/associations between environmental, maternal and infant factors, and OTU clusters.

Results

We identified six clusters of co-occurring OTUs. The first two components in the PLS regression explained 39% and 33% of the covariance between the maternal prenatal OTU clusters and immune cell populations in offspring at birth. A cluster in which Dialister, Escherichia, and Ruminococcus were predominant was associated with a lower proportion of granulocytes (p=0.002), and higher proportions of both central naïve CD4⁺ T cells (CD4⁺/CD45RA⁺/CD31⁻) (p<0.001) and naïve regulatory T cells (Treg) (CD4⁺/CD45RA⁺/FoxP3^low) (p=0.02) in cord blood. The association with central naïve CD4⁺ T cells persisted to 12 months of age.

Conclusion

This birth cohort study provides evidence consistent with past preclinical models that the maternal gut microbiota during pregnancy plays a role in shaping the composition of innate and adaptive elements of the infant’s immune system following birth.

How Hydroxyurea Alters the Gut Microbiome: A Longitudinal Study Involving Angolan Children with Sickle Cell Anemia

Sickle cell anemia (SCA) is an inherited hematological disorder and a serious global health problem, especially in Sub-Saharan Africa. Although hydroxyurea (HU) is the leading treatment for patients with SCA, its effects on the gut microbiome have not yet been explored. In this context, the aim of this study was to investigate this association by characterizing the gut microbiome of an Angolan SCA pediatric population before and after 6 months of HU treatment. A total of 66 stool samples were obtained and sequenced for the 16S rRNA gene (V3-V4 regions). Significant associations were observed in alpha and beta-diversity, with higher values of species richness for the children naïve for HU. We also noticed that children after HU had higher proportions of several beneficial bacteria, mostly short-chain fatty acids (SCFAs) producing species, such as Blautia luti, Roseburia inulinivorans, Eubacterium halli, Faecalibacterium, Ruminococcus, Lactobacillus rogosae, among others. In addition, before HU there was a higher abundance of Clostridium_g24, which includes C. bolteae and C. clostridioforme, both considered pathogenic. This study provides the first evidence of the HU effect on the gut microbiome and unravels several microorganisms that could be considered candidate biomarkers for disease severity and HU efficacy.

The Composition of Placental Microbiota and Its Association With Adverse Pregnancy Outcomes

To verify whether the placenta harbors bacteria, and to explore the composition of placental microbiota (if yes) and its association with adverse pregnancy outcomes. The placental microbiota was detected by 16S rRNA gene sequencing technology. In the process of detecting placental samples, exogenous marine bacterial DNA that does not exist in the human body was artificially added to obtain a visible 16S band. At the same time, the sterile samples, such as scissors, sheets, and cotton swabs, in delivery and operating rooms were collected as the environmental control samples. As a result, a total of 2,621,009 sequences were obtained from 71 samples, 88.9% of which came from artificially added exogenous bacterial DNA, suggesting that the placenta contained fewer bacteria. After removing the operational taxonomic units (OTUs) that coexisted in environmental controls, the placenta was annotated with 11 phyla, 22 classes, 43 orders, 79 families, and 157 genera. The β diversity analysis showed that there were significant differences in the placental microbiota between 10 women with gestational diabetes mellitus (GDM) (p AMOVA = 0.01) or 19 women with premature rupture of membranes (PROM) (p AMOVA = 0.004), and 21 women without adverse pregnancy outcomes, respectively. There were higher abundances of genera Bifidobacterium, Duncaniella, and Ruminococcus in the placenta samples of women with GDM. The genera of Bacteroides, Paraprevotella, and Ruminococcus were more enriched in the placental samples of women with PROM. The authors concluded that the placenta may harbor small amounts of microbiota, and significant differences in the dominant microbiota of the placenta were observed between those pregnant women with and without adverse pregnancy outcomes.

Lemierre Syndrome Due to Dialister pneumosintes: A Case Report

Although Dialister pneumosintes is a commensal microorganism of the oral cavity, it may sometimes cause severe systemic infections. We report a case of Lemierre syndrome (LS), which developed after D. pneumosintes infection, in a 73-year-old Japanese woman who was admitted to the hospital for throat pain, neck swelling, and fever for 3 days. She had a 3-month history of neglected dental caries, gingivitis, and periodontitis. Physical examination revealed right tonsillar erythema and swelling, and computed tomography (CT) showed peritonsillar and retropharyngeal abscesses. Ampicillin/sulbactam was promptly administered after collecting two sets of blood cultures. Surgical drainage for peritonsillar and retropharyngeal abscesses was also conducted on the second hospital day. Although only commensal oral microflora grew in the culture from the drained pus, Gram-negative bacilli were confirmed in the anaerobic blood cultures. Metronidazole was administered intravenously; however, the fever and neck swelling persisted. Repeat CT performed on the fifth hospital day revealed right internal jugular vein thrombosis, a known complication of tonsillitis and pharyngitis once the infection extends beyond the oropharynx. We diagnosed she had coexisting LS, and anticoagulant therapy was added to her treatment regimen. Her condition improved, and she was discharged after completing 3 weeks of antibiotics. Conventional methods failed to identify the isolated bacterium, and 16S rRNA sequencing ultimately identified it as D. pneumosintes. In a literature review of bacteremia due to D. pneumosintes, poor oral hygiene was considered a probable risk factor for invasive D. pneumosintes infection. We consider this to be the case in our patient who presented with dental caries, gingivitis, and periodontitis. In addition, all cases revealed that the 16S rRNA gene sequencing is useful for identifying this species. Although the diagnosis of LS by physical examination is difficult, physicians should always consider it as a potential complication of infections in the pharyngeal area.

Sinogenic polymicrobial anaerobic orbital cellulitis: the importance of source control and broad empirical antibiotics

A man in his twenties with a history of recurrent sinusitis was urgently referred to the emergency department (ED) by an out-of-hours general practitioner following a 2-day history of increasing right eye pain, redness and swelling after a week of coryzal symptoms. He denied visual impairment and any history of recent dental pain or procedures. Initial assessment in ED noted fever, tachycardia and hypotension. Video consultation with ophthalmologist in the ED identified proptosis, periorbital erythema and chemosis with full eye movement solely affecting the right eye. Visual acuity of 6/6 was confirmed in both eyes. After review by the ear, nose and throat (ENT) team, a diagnosis of sinogenic right orbital cellulitis was made, empirical antibiotics started and care transferred to the ENT team for immediate surgical intervention. 48 hours postoperatively, the patient acutely deteriorated, developing ophthalmoplegia and visual acuity of 6/95 in the right eye. Repeat imaging demonstrated a deteriorating picture and urgent surgery was organised at a neighbouring hospital's specialist ENT unit combined with a change to his antibiotics. On day 4, 1 day following transfer, an anaerobic bacterium, Eggerthia catenaformis, was isolated from blood cultures collected on admission. The patient improved clinically following the second surgery and targeted antimicrobial therapy, eventually being discharged 10 days after initial presentation. In addition to E. catenaformis, the Anaerobic Reference Unit (Cardiff) identified two further anaerobic bacteria, Parvimonas micra and Dialister pneumosintes This paper presents the first documented case of polymicrobial anaerobic orbital cellulitis secondary to acute bacterial sinusitis. Moreover, this case underpins the importance of broad empirical antibiotics coupled with surgical source control to effectively manage a rare but sight-threatening and life-threatening disease.

Profile of the oral microbiota from preconception to the third trimester of pregnancy and its association with oral hygiene practices

Background

The oral microbiota plays vital roles in both oral and systemic health, but limited studies have explored the transition of the female oral microbiota from preconception to pregnancy along with pronounced hormonal fluctuations.

Aim

To characterize the oral microbiota among women in preconception and pregnancy through a prospective study and to explore the associations between the oral microbiota and oral hygiene practices.

Methods

A total of 202 unstimulated saliva samples were collected from 101 women in both preconception and late pregnancy. The oral microbiota was analyzed using 16S rRNA gene sequencing.

Results

The Ace and phylogenetic diversity (PD) index were significantly lower in the third trimester than preconception. The pathogenic taxa Prevotella and Atopobium parvulum were significantly higher during late pregnancy than preconception. Women with overall better oral hygiene practice showed lower richness     and diversity     in preconception compared to women with poorer oral hygiene practice. The abundance of pathogens such as Dialister during both preconception and pregnancy decreased among women with better oral hygiene practice.

Conclusions

The composition of the oral microbiota changed slightly from preconception to late pregnancy, with more pathogens in saliva samples during pregnancy. Improving oral hygiene practices has the potential to maintain oral micro-ecological balance.

Prebiotic characteristics of arabinogalactans during in vitro fermentation through multi-omics analysis

BACKGROUND AND OBJECTIVES

Dietary fibers have beneficial effects on human health through the interaction with gut microbiota. Larch wood arabinogalactan (LA-AG) is one kind of complex soluble dietary fibers that may be utilized by human gut microbiota.

METHODS AND RESULTS

In this study, the LA-AG degradation by gut microbiota were characterized by investigating the change of LA-AG, microbiota composition, and the production of short-chain fatty acids (SCFAs), lactic acid, succinic acid, as well as volatile organic metabolites. During the fermentation, pH decreased continuously, along with the organic acids (especially acetic acid and lactic acid) accumulating. LA-AG was degraded by gut microbiota then some beneficial metabolites were produced. In addition, LA-AG inhibited the proliferation of some gut microbiota (Unclassified_Enterobacteriaceae and Citrobacter) and the accumulation of some metabolites (Sulfide and indole) released by gut microbiota.

CONCLUSION

LA-AG was partly fermentable fibers with prebiotic potential for human gut health.

A Metatranscriptomics Survey of Microbial Diversity on Surfaces Post-Intervention of cleanSURFACES® Technology in an Intensive Care Unit

Hospital-acquired infections (HAIs) pose a serious threat to patients, and hospitals spend billions of dollars each year to reduce and treat these infections. Many HAIs are due to contamination from workers’ hands and contact with high-touch surfaces. Therefore, we set out to test the efficacy of a new preventative technology, AIONX^® Antimicrobial Technologies, Inc’s cleanSURFACES^®, which is designed to complement daily chemical cleaning events by continuously preventing re-colonization of surfaces. To that end, we swabbed surfaces before (Baseline) and after (Post) application of the cleanSURFACES^® at various time points (Day 1, Day 7, Day 14, and Day 28). To circumvent limitations associated with culture-based and 16S rRNA gene amplicon sequencing methodologies, these surface swabs were processed using metatranscriptomic (RNA) analysis to allow for comprehensive taxonomic resolution and the detection of active microorganisms. Overall, there was a significant (P < 0.05) global reduction of microbial diversity in Post-intervention samples. Additionally, Post sample microbial communities clustered together much more closely than Baseline samples based on pairwise distances calculated with the weighted Jaccard distance metric, suggesting a defined shift after product application. This shift was characterized by a general depletion of several microbes among Post samples, with multiple phyla also being reduced over the duration of the study. Notably, specific clinically relevant microbes, including Staphylococcus aureus, Clostridioides difficile and Streptococcus spp., were depleted Post-intervention. Taken together, these findings suggest that chemical cleaning events used jointly with cleanSURFACES^® have the potential to reduce colonization of surfaces by a wide variety of microbes, including many clinically relevant pathogens.

How Do Polymer Coatings Affect the Growth and Bacterial Population of a Biofilm Formed by Total Human Salivary Bacteria?-A Study by 16S-RNA Sequencing

Antimicrobial surface modifications are required to prevent biomaterial-associated biofilm infections, which are also a major concern for oral implants. The aim of this study was to evaluate the influence of three different coatings on the biofilm formed by human saliva. Biofilms grown from human saliva on three different bioactive poly(oxanorbornene)-based polymer coatings (the protein-repellent PSB: poly(oxanorbornene)-based poly(sulfobetaine), the protein-repellent and antimicrobial PZI: poly(carboxyzwitterion), and the mildly antimicrobial and protein-adhesive SMAMP: synthetic mimics of antimicrobial peptides) were analyzed and compared with the microbial composition of saliva, biofilms grown on uncoated substrates, and biofilms grown in the presence of chlorhexidine digluconate. It was found that the polymer coatings significantly reduced the amount of adherent bacteria and strongly altered the microbial composition, as analyzed by 16S RNA sequencing. This may hold relevance for maintaining oral health and the outcome of oral implants due to the existing synergism between the host and the oral microbiome. Especially the reduction of some bacterial species that are associated with poor oral health such as Tannerella forsythia and Fusobacterium nucleatum (observed for PSB and SMAMP), and Prevotella denticola (observed for all coatings) may positively modulate the oral biofilm, including in situ.

A Case of Dialister pneumosintes Bacteremia-Associated Neck and Mediastinal Abscess

BACKGROUND Dialister pneumosintes is a suspected periodontal pathogen. It can affect different parts of the body either by hematogenous transmission or regional spread. Here, we report a case of 30-year-old previously healthy woman diagnosed with mediastinal and neck abscess caused by this pathogen. CASE REPORT A 30-year-old woman presented with a 1-day history of fever, vomiting, and diarrhea. She was on her last dose of a 2-week course of oral antibiotic for suspected dental abscess. On admission, parenteral broad-spectrum antibiotic was started for sepsis of unknown source. Because of intermittent spike of high temperature despite being on an antibiotic, cross-sectional imaging was performed, which revealed a superior mediastinal abscess with extension in the neck. She was referred to the ENT surgeon for incision and drainage of the collection. However, the procedure was complicated by injury to the right internal jugular vein. Her postoperative period was also convoluted with the development of pulmonary embolism, followed by deep vein thrombosis of the right upper limb. Her pus polymerase chain reaction test detected 16s rRNA gene, suggestive of gram-negative anaerobic bacilli, and anaerobic blood culture grew Dialister pneumosintes. After a prolonged course of illness and antibiotic treatment, she recovered well, and now is back to her normal activities. CONCLUSIONS Potential life-threatening complications may develop from periodontal infection by this microorganism. In patients being treated for sepsis of unknown origin, not responding to antibiotic treatment, and with a history of recent periodontal infection, a deep-seated abscess needs to be considered.

Causal effects in microbiomes using interventional calculus

Causal inference in biomedical research allows us to shift the paradigm from investigating associational relationships to causal ones. Inferring causal relationships can help in understanding the inner workings of biological processes. Association patterns can be coincidental and may lead to wrong conclusions about causality in complex systems. Microbiomes are highly complex, diverse, and dynamic environments. Microbes are key players in human health and disease. Hence knowledge of critical causal relationships among the entities in a microbiome, and the impact of internal and external factors on microbial abundance and their interactions are essential for understanding disease mechanisms and making appropriate treatment recommendations. In this paper, we employ causal inference techniques to understand causal relationships between various entities in a microbiome, and to use the resulting causal network to make useful computations. We introduce a novel pipeline for microbiome analysis, which includes adding an outcome or "disease" variable, and then computing the causal network, referred to as a "disease network", with the goal of identifying disease-relevant causal factors from the microbiome. Internventional techniques are then applied to the resulting network, allowing us to compute a measure called the causal effect of one or more microbial taxa on the outcome variable or the condition of interest. Finally, we propose a measure called causal influence that quantifies the total influence exerted by a microbial taxon on the rest of the microiome. Our pipeline is robust, sensitive, different from traditional approaches, and able to predict interventional effects without any controlled experiments. The pipeline can be used to identify potential eubiotic and dysbiotic microbial taxa in a microbiome. We validate our results using synthetic data sets and using results on real data sets that were previously published.

Putative Pathobionts in HLA-B27-Associated Spondyloarthropathy

Spondyloarthritis (SpA) is a group of immune mediated inflammatory diseases with a strong association to the major histocompatibility (MHC) class I molecule, HLA-B27. Although the association between HLA-B27 and AS has been known for almost 50 years, the mechanisms underlying disease pathogenesis are elusive. Over the years, three hypotheses have been proposed to explain HLA-B27 and disease association: 1) HLA B27 presents arthritogenic peptides and thus creates a pathological immune response; 2) HLA-B27 misfolding causes endoplasmic reticulum (ER) stress which activates the unfolded protein response (UPR); 3) HLA-B27 dimerizes on the cell surface and acts as a target for natural killer (NK) cells. None of these hypotheses explains SpA pathogenesis completely. Evidence supports the hypothesis that HLA-B27-related diseases have a microbial pathogenesis. In animal models of various SpAs, a germ-free environment abrogates disease development and colonizing these animals with gut commensal microbes can restore disease manifestations. The depth of microbial influence on SpA development has been realized due to our ability to characterize microbial communities in the gut using next-generation sequencing approaches. In this review, we will discuss various putative pathobionts in the pathogenesis of HLA-B27-associated diseases. We pursue whether a single pathobiont or a disruption of microbial community and function is associated with HLA-B27-related diseases. Furthermore, rather than a specific pathobiont, metabolic functions of various disease-associated microbes might be key. While the use of germ-free models of SpA have facilitated understanding the role of microbes in disease development, future studies with animal models that mimic diverse microbial communities instead of mono-colonization are indispensable. We discuss the causal mechanisms underlying disease pathogenesis including the role of these pathobionts on mucin degradation, mucosal adherence, and gut epithelial barrier disruption and inflammation. Finally, we review the various uses of microbes as therapeutic modalities including pre/probiotics, diet, microbial metabolites and fecal microbiota transplant. Unravelling these complex host-microbe interactions will lead to the development of new targets/therapies for alleviation of SpA and other HLA-B27 associated diseases.

Gut Microbiome Reveals Specific Dysbiosis in Primary Osteoporosis

Object: Primary osteoporosis (PO) is the most common bone disease, which is characterized by decreased bone mass, damage of bone tissue microstructure, increased bone fragility, and is prone to fracture. Gut microbiome may be involved in bone metabolism of PO through gut-brain axis regulation of immune system and endocrine system, however, the specific mechanism is still unclear. The purpose of this study was to characterize the gut microbiome of patients with PO and its possible role in the occurrence and development of the disease. Methods: Fecal samples were collected from 48 PO patients and 48 healthy controls (HC). The composition of gut microbiome community was analyzed by 16s rDNA amplification sequencing, and the difference of gut microbiome composition between PO patients and HC individuals was compared. PICRUSt was also used to predict the biological function of gut microbiome in patients with PO, and to explore its possible role in the occurrence and development of this disease. The classification model is constructed by random forest algorithm so as to screen the key biomarkers. Result: The diversity of gut microorganisms in PO patients was significantly higher than that in HC group (p < 0.05) and there was significant difference in microbial composition in PO group. The abundance of Dialister (0.036 vs. 0.004, p < 0.001) and Faecalibacterium (0.331 vs. 0.132, p < 0.001) were significantly enriched which were the key flora related to PO. Although no significant correlation between bone mineral density and the richness of microbial communities are found, PICRUST results show that there are a wide range of potential pathways between gut microbiome and PO patients, including genetic information processing, metabolism, environmental information processing, cellular processes, human diseases, and organic systems. Notably, the discriminant model based on dominant microflora can effectively distinguish PO from HC (AUC = 93.56). Conclusions: The findings show that PO is related to the change of gut microbiome, especially the enriched Dialister and Faecalibacterium genera, which give new clues to understand the disease and provide markers for the diagnosis and new strategies for intervention treatment of the disease.

Comparative analysis of the vaginal microbiome of pregnant women with either Trichomonas vaginalis or Chlamydia trachomatis

Background

Although the significance of the human vaginal microbiome for health and disease is increasingly acknowledged, there is paucity of data on the differences in the composition of the vaginal microbiome upon infection with different sexually transmitted pathogens.

Method

The composition of the vaginal bacterial community of women with Trichomonas vaginalis (TV, N = 18) was compared to that of women with Chlamydia trachomatis (CT, N = 14), and to that of controls (N = 21) (women negative for TV, CT and bacterial vaginosis). The vaginal bacterial composition was determined using high throughput sequencing with the Ion 16S metagenomics kit of the variable regions 2, 4 and 8 of the bacterial 16S ribosomal RNA gene from the vaginal swab DNA extract of the women. QIIME and R package “Phyloseq” were used to assess the α- and β-diversity and absolute abundance of the 16S rRNA gene per sample in the three groups. Differences in taxa at various levels were determined using the independent T-test.

Results

A total of 545 operational taxonomic units (OTUs) were identified in all the three groups of which 488 occurred in all three groups (core OTUs). Bacterial α-diversity, by both Simpson’s and Shannon’s indices, was significantly higher, (p = 0.056) and (p = 0.001) respectively, among women with either TV or CT than among controls (mean α-diversity TV-infected > CT-infected > Controls). At the genus level, women infected with TV had a significantly (p < 0.01) higher abundance of Parvimonas and Prevotella species compared to both controls and CT-infected women, whereas women infected with CT had a significantly (p < 0.05) higher abundance of Anaerococcus, Collinsella, Corynebacterium and Dialister.

Conclusion

The vaginal microbiomes of TV and CT-infected women were markedly different from each other and from women without TV and CT. Future studies should determine whether the altered microbiomes are merely markers of disease, or whether they actively contribute to the pathology of the two genital infections.

The Gut Microbiome and Metabolome of Two Riparian Communities in the Amazon

During the last decades it has become increasingly clear that the microbes that live on and in humans are critical for health. The communities they form, termed microbiomes, are involved in fundamental processes such as the maturation and constant regulation of the immune system. Additionally, they constitute a strong defense barrier to invading pathogens, and are also intricately linked to nutrition. The parameters that affect the establishment and maintenance of these microbial communities are diverse, and include the genetic background, mode of birth, nutrition, hygiene, and host lifestyle in general. Here, we describe the characterization of the gut microbiome of individuals living in the Amazon, and the comparison of these microbial communities to those found in individuals from an urban, industrialized setting. Our results showed striking differences in microbial communities from these two types of populations. Additionally, we used high-throughput metabolomics to study the chemical ecology of the gut environment and found significant metabolic changes between the two populations. Although we cannot point out a single cause for the microbial and metabolic changes observed between Amazonian and urban individuals, they are likely to include dietary differences as well as diverse patterns of environmental exposure. To our knowledge, this is the first description of gut microbial and metabolic profiles in Amazonian populations, and it provides a starting point for thorough characterizations of the impact of individual environmental conditions on the human microbiome and metabolome.

Filifactor alocis and Dialister pneumosintes in a Mexican population affected by periodontitis and rheumatoid arthritis: An exploratory study

Filifactor alocis and Dialister pneumosintes have been associated with the initiation and progression of periodontitis (PE). We determined and compared the frequency of both bacteria in patients with PE, rheumatoid arthritis (RA), and PE/RA simultaneously. Detection was performed by polymerase chain reaction in the subgingival biofilm. Bacteria were more frequent in patients with PE, and clinical periodontal parameters such as pocket depth (PD) and clinical attachment loss (CAL) were significantly higher in patients with PE/RA. F. alocis and D. pneumosintes could influence PD and CAL, hence participating in the initiation and progression of PE in patients with RA.

Yogurt improves insulin resistance and liver fat in obese women with nonalcoholic fatty liver disease and metabolic syndrome: a randomized controlled trial

BACKGROUND

Because consumption of conventional yogurt has beneficial effects in a healthy population, and insulin resistance (IR) is the mutual pathogenesis in nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS), we hypothesized that yogurt would ameliorate IR in patients with NAFLD and MetS.

OBJECTIVES

The aim of this study was to investigate the effects of yogurt on IR and secondary endpoints including liver fat, gut microbiota, and serum biomarkers of inflammation and oxidative stress in obese women with NAFLD and MetS.

METHODS

One hundred obese women aged 36-66 y with both NAFLD and MetS were randomly assigned to consume 220 g/d of either conventional yogurt or milk for 24 wk. At baseline and week 24, we measured anthropometric indices, serum glucose, insulin, lipids, and cytokines in all participants, and liver fat and gut microbiota in 20 participants randomly selected from each group.

RESULTS

Forty-eight participants from the yogurt group and 44 from the milk group completed the intervention. Compared with milk, yogurt significantly decreased the homeostasis model assessment of insulin resistance (-0.53; 95% CI: -1.03, -0.02), fasting insulin (-2.77 mU/L; 95% CI: -4.91, -0.63 mU/L), 2-h insulin (-25.5 mU/L; 95% CI: -33.0, -17.9 mU/L), 2-h area under the curve for insulin (-29.4 mU/L · h; 95% CI: -44.0, -14.8 mU/L · h), alanine aminotransferase (-4.65 U/L; 95% CI: -8.67, -0.64 U/L), intrahepatic lipid (-3.44%; 95% CI: -6.19%, -0.68%), and hepatic fat fraction (-3.48%; 95% CI: -6.34%, -0.63%). Yogurt also decreased serum LPS (-0.31 EU/mL; 95% CI: -0.48, -0.14 EU/mL), fibroblast growth factor 21 (-57.76 pg/mL; 95% CI: -86.32, -29.19 pg/mL), lipids, and biomarkers of inflammation and oxidative stress, and altered gut microbiota composition. Mediation analysis showed that yogurt may improve IR by reducing serum lipids, inflammation, oxidative stress, and LPS.

CONCLUSIONS

Yogurt was better than milk at ameliorating IR and liver fat in obese Chinese women with NAFLD and MetS, possibly by improving lipid metabolism, reducing inflammation, oxidative stress, and LPS, and changing the gut microbiota composition. This trial was registered at www.chictr.org.cn as ChiCTR-IPR-15006801.

Hepatic abscess due to Dialister pneumosintes - A case report

Dialister pneumosintes is an obligate anaerobic Gram-negative rod associated with infections of the oral cavity. We report on a previously healthy, 51-year-old woman who presented with a liver abscess caused by Dialister pneumosintes as a complication of a dental abscess. The microorganism was identified by using a broad-range bacterial 16S rRNA gene PCR in the liver exudate. The patient was cured after abscess drainage and 4-week antibiotic treatment. Our case highlights the importance of a good history and physical examination when taking care of patients admitted for pyogenic liver abscess.

Microbiome networks and change-point analysis reveal key community changes associated with cystic fibrosis pulmonary exacerbations

Over 90% of cystic fibrosis (CF) patients die due to chronic lung infections leading to respiratory failure. The decline in CF lung function is greatly accelerated by intermittent and progressively severe acute pulmonary exacerbations (PEs). Despite their clinical impact, surprisingly few microbiological signals associated with PEs have been identified. Here we introduce an unsupervised, systems-oriented approach to identify key members of the microbiota. We used two CF sputum microbiome data sets that were longitudinally collected through periods spanning baseline health and PEs. Key taxa were defined based on three strategies: overall relative abundance, prevalence, and co-occurrence network interconnectedness. We measured the association between changes in the abundance of the key taxa and changes in patient clinical status over time via change-point detection, and found that taxa with the highest level of network interconnectedness tracked changes in patient health significantly better than taxa with the highest abundance or prevalence. We also cross-sectionally stratified all samples into the clinical states and identified key taxa associated with each state. We found that network interconnectedness most strongly delineated the taxa among clinical states, and that anaerobic bacteria were over-represented during PEs. Many of these anaerobes are oropharyngeal bacteria that have been previously isolated from the respiratory tract, and/or have been studied for their role in CF. The observed shift in community structure, and the association of anaerobic taxa and PEs lends further support to the growing consensus that anoxic conditions and the subsequent growth of anaerobic microbes are important predictors of PEs.

Episodes of significant worsening of cystic fibrosis symptoms, known as pulmonary exacerbations (PEs), are associated with oxygen-deficient (anoxic) conditions and increased activity of ‘anaerobic’ bacteria, which thrive in the absence of oxygen. Researchers in Canada, led by David Guttman at the University of Toronto, compared genetic data on microbial populations in sputum samples collected during PEs and at times of better health. The study revealed a strong correlation between the activity and interactions among anaerobic bacteria and the onset of PEs. Investigating the significance of these changes in the lung environment and its microbial populations may help design treatment strategies to reduce the frequency of PEs and their potentially fatal consequences. The authors suggest that antibiotics that specifically target anaerobic bacteria may prove beneficial, as may hyperbaric oxygen therapy, which oxygenates the lung tissue.

Gut microbiota in children and altered profiles in juvenile idiopathic arthritis

Microbial diversity plays a key role in the maintenance of intestinal homeostasis and in the development of the immune system in the gut mucosa. Maybe one of the most important function of our gut microbiota is the immune system education, in particular the discrimination of friends from foes that occurs during childhood. In addition to bacterial antigens, several metabolites of microbial origin have a crucial role in training of the immune system, such as Short Chain Fatty Acids (SCFAs). There are many evidences on the role of the gut microbiota in rheumatic diseases, in particular modifications of microbiota composition causing dysbiosis that, in turn, can induce gut permeability, and thus immunological imbalance and trigger inflammation. In particular, immune cells can reach extra-intestinal sites, such as joints and trigger local inflammation. Childhood is a crucial period of life for development and evolution of the gut microbiota, especially for the acquisition of fundamental functions such as immunotolerance of commensal microorganisms. For this reason, gut dysbiosis is gaining interest as a potential pathogenetic factor for Juvenile Idiopathic Arthritis (JIA). Here we summarized the studies conducted on JIA patients in which a pro-arthritogenic microbial profiles has been observed; this, together with a depletion of microbial biodiversity, clearly distinguish patients' from healthy subjects' microbiota. Further studies are however needed to better clarify the role of microbiota in JIA pathogenesis.

Novel Pathogens in Periodontal Microbiology

Periodontitis is a polymicrobial disease caused by complex interactions between distinct pathogens in a biofilm resulting in the destruction of periodontal tissues. It seems evident that unknown microorganisms might be involved in onset or progression of periodontitis. For many decades, research in the field of oral microbiology failed to identify certain subgingival microbiota due to technical limitations but, over a period of 12 years using molecular approaches and sequencing techniques, it became feasible to reveal the existence of new periodontal pathogens. Therefore, it is evident that in addition to conventional periodontal pathogens, other microbes might be involved in onset and progression of periodontitis. The novel pathogens enlisted under periodontal phylogeny include Cryptobacterium curtum, Dialister pneumosintes, Filifactor alocis, Mitsuokella dentalis, Slackia exigua, Selenomonas sputigena, Solobacterium moorei, Treponema lecithinolyticum, and Synergistes. The polymicrobial etiology of periodontitis has been elucidated by comprehensive techniques, and studies throwing light on the possible virulence mechanisms possessed by these novel periodontal pathogens are enlisted.

Brief Report: Dialister as a Microbial Marker of Disease Activity in Spondyloarthritis

OBJECTIVE

Dysbiosis of the intestinal microbiota has been widely established in inflammatory bowel disease (IBD). There is significant clinical and genetic overlap between spondyloarthritis (SpA) and IBD, and up to 50% of all patients with SpA exhibit microscopic signs of bowel inflammation, often bearing particular resemblance to early Crohn's disease, a subtype of IBD. This study was undertaken to assess the relationship between intestinal microbial composition, gut histology, and disease activity markers in SpA.

METHODS

Gene analysis by 16S ribosomal RNA amplicon sequencing was used to compare the microbial composition in ileal and colonic biopsy specimens from 27 patients with SpA (14 with microscopic bowel inflammation, 13 without) and 15 healthy control subjects (ileal samples from all 15 subjects and colonic samples from 6). Spearman's rank correlation tests were used to assess correlations of the microbial composition with disease activity measures.

RESULTS

The intestinal inflammation status (histologically normal versus acute or chronic inflammation) was strongly associated with the mucosal microbiota profile of patients with SpA. In inflamed biopsy tissue, the detected bacterial community composition clustered separately from that in noninflamed biopsy tissue (P < 0.05 by permutational multivariate analysis of variance, using hierarchical clustering on Bray-Curtis distances). Interestingly, abundance of the genus Dialister was found to be positively correlated with the Ankylosing Spondylitis Disease Activity Score (Spearman's rho = 0.62, false discovery rate-corrected q < 0.01). This finding was further supported by the low frequency of Dialister observed in noninflamed ileal and colonic biopsy tissue from patients with SpA and healthy controls.

CONCLUSION

These findings demonstrate a significant difference in the intestinal microbial composition in patients with SpA who have microscopic gut inflammation compared to those without microscopic gut inflammation. Moreover, Dialister may represent a potential microbial marker of disease activity in SpA.

Alteration of Fecal Microbiota Profiles in Juvenile Idiopathic Arthritis. Associations with HLA-B27 Allele and Disease Status

Alteration of gut microbiota is involved in several chronic inflammatory and autoimmune diseases, including rheumatoid arthritis, and gut microbial “pro-arthritogenic” profiles have been hypothesized. Intestinal inflammation may be involved in spondyloarthropathies and in a subset of patients affected by Juvenile Idiopathic Arthritis (JIA), the most common chronic rheumatic disease of childhood. We compared the fecal microbiota composition of JIA patients with healthy subjects (HS), evaluating differences in microbial profiles between sub-categories of JIA, such as enthesitis-related arthritis (JIA-ERA), in which inflammation of entheses occurs, and polyarticular JIA, non-enthesitis related arthritis (JIA-nERA). Through taxon-level analysis, we discovered alteration of fecal microbiota components that could be involved in subclinical gut inflammation, and promotion of joint inflammation. We observed abundance in Ruminococcaceae in both JIA categories, reduction in Clostridiaceae and Peptostreptococcaceae in JIA-ERA, and increase in Veillonellaceae in JIA-nERA, respectively, compared with HS. Among the more relevant genera, we found an increase in Clostridium cluster XIVb, involved in colitis and arthritis, in JIA-ERA patients compared with HS, and a trend of decrease in Faecalibacterium, known for anti-inflammatory properties, in JIA-nERA compared with JIA-ERA and HS. Differential abundant taxa identified JIA patients for the HLA-B27 allele, including Bilophila, Clostridium cluster XIVb, Oscillibacter, and Parvimonas. Prediction analysis of metabolic functions showed that JIA-ERA metagenome was differentially enriched in bacterial functions related to cell motility and chemotaxis, suggesting selection of potential virulence traits. We also discovered differential microbial profiles and intra-group variability among active disease and remission, suggesting instability of microbial ecosystem in autoimmune diseases with respect to healthy status. Similarly to other chronic autoimmune and inflammatory diseases, different microbial profiles, as observed among different JIA subgroups compared to HS, and potential functional acquisition related to migration, could promote inflammation and contribute to the disease pathogenesis.

Dysbiosis of small intestinal microbiota in liver cirrhosis and its association with etiology

Cirrhosis-associated duodenal dysbiosis is not yet clearly defined. In this research, duodenal mucosal microbiota was analyzed in 30 cirrhotic patients and 28 healthy controls using 16S rRNA gene pyrosequencing methods. The principal coordinate analysis revealed that cirrhotic patients were colonized by remarkable different duodenal mucosal microbiota in comparison with controls. At the genus level, Veillonella, Megasphaera, Dialister, Atopobium, and Prevotella were found overrepresented in cirrhotic duodenum. And the duodenal microbiota of healthy controls was enriched with Neisseria, Haemophilus, and SR1 genera incertae sedis. On the other hand, based on predicted metagenomes analyzed, gene pathways related to nutrient absorption (e.g. sugar and amino acid metabolism) were highly abundant in cirrhosis duodenal microbiota, and functional modules involved in bacterial proliferation and colonization (e.g. bacterial motility proteins and secretion system) were overrepresented in controls. When considering the etiology of cirrhosis, two operational taxonomic units (OTUs), OTU-23 (Neisseria) and OTU-36 (Gemella), were found discriminative between hepatitis-B-virus related cirrhosis and primary biliary cirrhosis. The results suggest that the structure of duodenal mucosa microbiota in cirrhotic patients is dramatically different from healthy controls. The duodenum dysbiosis might be related to alterations of oral microbiota and changes in duodenal micro-environment.

Antimicrobial resistance genes and modelling of treatment failure in bacterial vaginosis: clinical study of 289 symptomatic women

Clinical management of bacterial vaginosis (BV) is difficult owing to inaccurate diagnostic tests, limited drug choices, and a high rate of recurrence. To our knowledge, there has not been a previous study of antimicrobial resistance (AMR) genes in community practice using next-generation sequencing (NGS). A case-control study (1 : 1 age-matched with and without BV) was undertaken in a series of 326 nongravid women of reproductive age with symptoms of BV to determine the prevalence of AMR genes. NGS was used to describe the complete vaginal microbiota and identify bacterial genes associated with resistance to: macrolides and/or lincosamides - ermA, ermB, ermC, erM, ermTR and mefA; tetracyclines, β-lactams, streptomycin, gentamicin and/or tobramycin - acrA, acrB, mecA, tet, tetA, tolC and aac2; 5-nitroimadazoles - nim and nimB; and triazoles - cdr1 and mdr1. An evidence base was created to inform treatment decisions applicable to individual patients. AMR genes were identified in all drug classes: macrolides, 35.2 %; lincosamides, 35.6 %; tetracyclines, 21.8 %; aminoglycosides (streptomycin, gentamicin and tobramycin), 5.2 % each; 5-nitroimidazoles, 0.3 %; and triazoles, 18.7 %. There was more than a fourfold-higher frequency of AMR genes in pathogens from BV than from non-BV patients for macrolides (58.2 versus 12.3 %, respectively), lincosamides (58.9 versus 12.3 %) and tetracyclines (35.6 versus 8.0 %) (Fisher's exact test; all p < 0.001). For each patient with BV, the spectrum of resistance genes was matched to the pathogens present. AMR genes were present in the majority of vaginal microbiomes of patients with symptoms of BV.

Dialister pneumosintes bacteremia caused by dental caries and sinusitis

A 62-year-old Japanese woman was hospitalized at the Department of Senology for positive signals on two sets of blood cultures obtained in the Emergency Department. The initial physical examination with enhanced computed tomography of the chest and abdomen did not identify the infectious source. Dialister pneumosintes was identified on 16S rRNA sequencing, and dental caries with sinusitis were subsequently diagnosed based on a dental examination and magnetic resonance imaging. History taking with respect to dental hygiene and oral examinations should be performed in daily clinical practice, especially in immunosuppressed patients.

High-throughput 16S rRNA gene sequencing reveals alterations of intestinal microbiota in myalgic encephalomyelitis/chronic fatigue syndrome patients

Human intestinal microbiota plays an important role in the maintenance of host health by providing energy, nutrients, and immunological protection. Intestinal dysfunction is a frequent complaint in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients, and previous reports suggest that dysbiosis, i.e. the overgrowth of abnormal populations of bacteria in the gut, is linked to the pathogenesis of the disease. We used high-throughput 16S rRNA gene sequencing to investigate the presence of specific alterations in the gut microbiota of ME/CFS patients from Belgium and Norway. 43 ME/CFS patients and 36 healthy controls were included in the study. Bacterial DNA was extracted from stool samples, PCR amplification was performed on 16S rRNA gene regions, and PCR amplicons were sequenced using Roche FLX 454 sequencer. The composition of the gut microbiota was found to differ between Belgian controls and Norwegian controls: Norwegians showed higher percentages of specific Firmicutes populations (Roseburia, Holdemania) and lower proportions of most Bacteroidetes genera. A highly significant separation could be achieved between Norwegian controls and Norwegian patients: patients presented increased proportions of Lactonifactor and Alistipes, as well as a decrease in several Firmicutes populations. In Belgian subjects the patient/control separation was less pronounced, however some abnormalities observed in Norwegian patients were also found in Belgian patients. These results show that intestinal microbiota is altered in ME/CFS. High-throughput sequencing is a useful tool to diagnose dysbiosis in patients and could help designing treatments based on gut microbiota modulation (antibiotics, pre and probiotics supplementation).

The complex vaginal flora of West African women with bacterial vaginosis

Background

The spectrum of bacteria associated with bacterial vaginosis (BV) has recently expanded through taxonomic changes and the use of molecular methods. These methods have yet to be used in large-scale epidemiological studies in Africa where BV is highly prevalent.

Methods

An analysis of samples obtained during a clinical trial of the management of vaginal discharge in four West African countries. Samples were available from 1555 participants; 843 (54%) had BV. Nucleic acids of 13 bacterial genera or species potentially associated with BV were detected through the polymerase chain reaction.

Results

The associations between various components of the vaginal flora were complex. Excluding Lactobacillus, the other 12 micro-organisms were all associated with each other at the p≤0.001 level. The prevalence of various bacterial genera or species varied according to age, sexual activity and HIV status. In multivariate analysis, the presence of Gardnerella vaginalis, Bifidobacterium, Megasphaera elsdenii, Dialister, Mycoplasma hominis, Leptotrichia, and Prevotella were independently associated with BV as was the absence of Lactobacillus and Peptoniphilus. However, Mobiluncus, Atopobium vaginae, Anaerococcus, and Eggerthella were not independently associated with BV. Unexpectedly, after treatment with a regimen that included either metronidazole or tinidazole, the proportion of patients with a complete resolution of symptoms by day 14 increased with the number of bacterial genera or species present at enrolment.

Conclusions

Numerous bacterial genera or species were strongly associated with each other in a pattern that suggested a symbiotic relationship. BV cases with a simpler flora were less likely to respond to treatment. Overall, the vaginal flora of West African women with BV was reminiscent of that of their counterparts in industrialized countries.

[New anaerobic bacterial species in human infections]

This review offers succinct, precise, and complete information based on the available data concerning new anaerobic bacterial species involved in infectious diseases in humans. All hitherto undescribed species, those not previously implicated in clinical conditions, those with confirmed implication in human disease that have not been characterized, and those that have undergone taxonomic changes are considered to be "new".

Molecular detection of multiple emerging pathogens in sputa from cystic fibrosis patients

Background

There is strong evidence that culture-based methods detect only a small proportion of bacteria present in the respiratory tracts of cystic fibrosis (CF) patients.

Methodology/Principal Findings

Standard microbiological culture and phenotypic identification of bacteria in sputa from CF patients have been compared to molecular methods by the use of 16S rDNA amplification, cloning and sequencing. Twenty-five sputa from CF patients were cultured that yield 33 isolates (13 species) known to be pathogens during CF. For molecular cloning, 760 clones were sequenced (7.2±3.9 species/sputum), and 53 different bacterial species were identified including 16 species of anaerobes (30%). Discrepancies between culture and molecular data were numerous and demonstrate that accurate identification remains challenging. New or emerging bacteria not or rarely reported in CF patients were detected including Dolosigranulum pigrum, Dialister pneumosintes, and Inquilinus limosus.

Conclusions/Significance

Our results demonstrate the complex microbial community in sputa from CF patients, especially anaerobic bacteria that are probably an underestimated cause of CF lung pathology. Metagenomic analysis is urgently needed to better understand those complex communities in CF pulmonary infections.