Obligate Anaerobes Research Articles

Halo(natrono)archaea from hypersaline lakes can utilize sulfoxides other than DMSO as electron acceptors for anaerobic respiration.

Dimethylsulfoxide (DMSO) has long been known to support anaerobic respiration in a few species of basically aerobic extremely halophilic euryarchaea living in hypersaline lakes. Recently, it has also been shown to be utilized as an additional electron acceptor in basically anaerobic sulfur-reducing haloarchaea. Here we investigated whether haloarchaea would be capable of anaerobic respiration with other two sulfoxides, methionine sulfoxide (MSO) and tetramethylene sulfoxide (TMSO). For this, anaerobic enrichment cultures were inoculated with sediments from hypersaline salt and soda lakes in southwestern Siberia and southern Russia. Positive enrichments were obtained for both MSO and TMSO with yeast extract but not with formate or acetate as the electron donor. Two pure cultures obtained from salt lakes, either with MSO or TMSO, were obligate anaerobes closely related to sulfur-reducing Halanaeroarchaeum sulfurireducens, although the type strain of this genus was unable to utilize any sulfoxides. Two pure cultures isolated from soda lakes were facultatively anaerobic alkaliphilic haloarchaea using O2, sulfur and sulfoxides as the electron acceptors. One isolate was identical to the previously described sulfur-reducing Natrarchaeobaculum sulfurireducens, while another one, enriched at lower alkalinity, is forming a new species in the genus Halobiforma. Since all isolates enriched with either MSO or TMSO were able to respire all three sulfoxides including DMSO and the corresponding activities were cross-induced, it suggest that a single enzyme of the DMSO-reductase family with a broad substrate specificity is responsible for various sulfoxide-dependent respiration in haloarchaea.

Potential Contributions of Anaerobes in Cystic Fibrosis Airways

Cystic fibrosis (CF) is the most common, lethal genetic disease among the Caucasian population. The leading cause of mortality is recurrent acute exacerbations resulting in chronic airway inflammation and subsequent downward progression of pulmonary function. Traditionally, these periods of clinical deterioration have been associated with several principal pathogens. However, a growing body of literature has demonstrated a polymicrobial lower respiratory community compromised of facultative and obligate anaerobes. Despite the understanding of a complex bacterial milieu in CF patient airways, specific roles of anaerobes in disease progression have not been established. In this paper, we first present a brief review of the anaerobic microorganisms that have been identified within CF lower respiratory airways. Next, we discuss the potential contribution of these organisms to CF disease progression, in part by pathogenic potential and also through synergistic interaction with principal pathogens. Finally, we propose a variety of clinical scenarios in which these anaerobic organisms indirectly facilitate principal CF pathogens by modulating host defense and contribute to treatment failure by antibiotic inactivation. These mechanisms may affect patient clinical outcomes and contribute to further disease progression.

Impacts of sleep on the characteristics of dental biofilm

Dental biofilm present on the tooth surface is associated with oral diseases, such as dental caries and periodontal disease. Because bacterial numbers rapidly increase in saliva during sleep, oral care before sleeping is recommended for the prevention of chronic oral diseases. However, temporal circadian changes in the quantity and quality of dental biofilms are poorly understood. This study aimed to investigate the impacts of sleeping on dental biofilm amounts and compositions by using an in situ model. The use of this in situ model enabled us to investigate dental biofilm formed in the oral cavity and to perform a quantitative analysis. Subjects began wearing oral splints in the morning or before sleeping, and biofilm samples were collected at 8, 16, and 24 h after the subjects began wearing oral splints; these samples were then used in various experiments. No significant changes in the numbers of biofilm-forming bacteria were caused by sleep. However, the relative abundances of genera related to periodontitis (i.e., Fusobacterium and Prevotella) increased after awakening. In conclusion, the numbers of biofilm-forming bacteria were not affected by sleep, and the abundances of obligate anaerobes increased after sleep. This research may aid in defining efficacious preventive oral care.

Comparative Genomics Provides Insights into the Taxonomy of Azoarcus and Reveals Separate Origins of Nif Genes in the Proposed Azoarcus and Aromatoleum Genera.

Among other attributes, the Betaproteobacterial genus Azoarcus has biotechnological importance for plant growth-promotion and remediation of petroleum waste-polluted water and soils. It comprises at least two phylogenetically distinct groups. The “plant-associated” group includes strains that are isolated from the rhizosphere or root interior of the C4 plant Kallar Grass, but also strains from soil and/or water; all are considered to be obligate aerobes and all are diazotrophic. The other group (now partly incorporated into the new genus Aromatoleum) comprises a diverse range of species and strains that live in water or soil that is contaminated with petroleum and/or aromatic compounds; all are facultative or obligate anaerobes. Some are diazotrophs. A comparative genome analysis of 32 genomes from 30 Azoarcus-Aromatoleum strains was performed in order to delineate generic boundaries more precisely than the single gene, 16S rRNA, that has been commonly used in bacterial taxonomy. The origin of diazotrophy in Azoarcus-Aromatoleum was also investigated by comparing full-length sequences of nif genes, and by physiological measurements of nitrogenase activity using the acetylene reduction assay. Based on average nucleotide identity (ANI) and whole genome analyses, three major groups could be discerned: (i) Azoarcus comprising Az. communis, Az. indigens and Az. olearius, and two unnamed species complexes, (ii) Aromatoleum Group 1 comprising Ar. anaerobium, Ar. aromaticum, Ar. bremense, and Ar. buckelii, and (iii) Aromatoleum Group 2 comprising Ar. diolicum, Ar. evansii, Ar. petrolei, Ar. toluclasticum, Ar. tolulyticum, Ar. toluolicum, and Ar. toluvorans. Single strain lineages such as Azoarcus sp. KH32C, Az. pumilus, and Az. taiwanensis were also revealed. Full length sequences of nif-cluster genes revealed two groups of diazotrophs in Azoarcus-Aromatoleum with nif being derived from Dechloromonas in Azoarcus sensu stricto (and two Thauera strains) and from Azospira in Aromatoleum Group 2. Diazotrophy was confirmed in several strains, and for the first time in Az. communis LMG5514, Azoarcus sp. TTM-91 and Ar. toluolicum TT. In terms of ecology, with the exception of a few plant-associated strains in Azoarcus (s.s.), across the group, most strains/species are found in soil and water (often contaminated with petroleum or related aromatic compounds), sewage sludge, and seawater. The possession of nar, nap, nir, nor, and nos genes by most Azoarcus-Aromatoleum strains suggests that they have the potential to derive energy through anaerobic nitrate respiration, so this ability cannot be usefully used as a phenotypic marker to distinguish genera. However, the possession of bzd genes indicating the ability to degrade benzoate anaerobically plus the type of diazotrophy (aerobic vs. anaerobic) could, after confirmation of their functionality, be considered as distinguishing phenotypes in any new generic delineations. The taxonomy of the Azoarcus-Aromatoleum group should be revisited; retaining the generic name Azoarcus for its entirety, or creating additional genera are both possible outcomes.

Identification of population of bacteria from culture negative surgical site infection patients using molecular tool

BackgroundManaging surgical site infections, with negative culture report in routine diagnosis is a common dilemma in microbiology accounting more than 30% worldwide. The present study attempted to identify the presence of bacterial spp. if any in wound aspirates/swabs of culture negative surgical site infections of hospitalised patients using molecular tools.MethodsNinety-seven patients with post-operative SSI whose wound swabs/aspirate were negative in the conventional aerobic culture after 72 h of incubation were analysed by 16S rRNA gene specific broad range PCR. The amplified DNA fragments were sequenced by Sanger DNA sequencing method and homology of the sequence were matched using NCBI BLAST (NCBI, USA)ResultsOf the 97 patients, 16S rRNA based broad range PCR assay could identify the presence of bacterial pathogen in 53(54.63%) cases, of which 29 isolates were supposed to be of viable but non-culturable bacteria (VBNC), 07 were of obligatory anaerobes and 13 were of unculturable bacteria, 04 were with poly bacterial infections.ConclusionsOur study highlights the usefulness of PCR assay in detecting the presence of any VBNC, anaerobes and unculturable bacteria in SSI patients regardless of how well the bacteria may or may not grow in culture. Measures should be taken to use anaerobic culture system and PCR diagnosis along with conventional culture to detect the VBNC and unculturable bacteria where Gram stain is positive for better patient care.

Clinico-microbiological spectrum of anaerobic pyogenic infections in an Indian tertiary care teaching hospital: A two-year study.

Introduction:Anaerobes are important however the most neglected pathogens. Timely isolation of anaerobes can guide the clinician about the correct course of clinical treatment and thus reduce the mortality and also the problem of antimicrobial resistance.Materials and Methods:Tissue and/or pus aspirates were collected aseptically from infectious sites in the Robertson's cooked meat medium (RCM) and sent to anaerobic bacteriology laboratory for culture. Subcultures from RCM for each sample were done on neomycin blood agar and 5% sheep blood agar along with metronidazole disc (5μg). The plates were incubated in an anaerobic jar using GasPak for 72 hrs. The preliminary identification was performed by standard biochemical tests for both obligate and facultative anaerobic isolates. Speciations of obligate anaerobes were performed by Vitek 2 automated system.Results:Obligate anaerobes either single or polymicrobial were obtained in 38/216 (14.5 %) samples processed during the study period. Polymicrobial infections were reported in 21/216 (55.26%) samples and most commonly with obligate anaerobic gramnegative bacilli i.e. Prevotella-Porphyromonas and Bacteroides fragilis group. Most common monomicrobial anaerobic infections were observed with Veillonella spp. (n=4) and Porphyromonas spp. (n=4) followed by Bacteroides fragilis (n=3). Obligate anaerobes were predominantly isolated from skin and soft tissue infections (n=14) followed by surgical site infections (n=8).Conclusion:Although most of the infections are polymicrobial, a rise in the incidence of monomicrobial anaerobic infections has been noticed. Therefore, the performance of anaerobic cultures along with aerobic cultures is much needed for complete bacterial work-up of specimens from infectious sites and better patient management.

CHARACTERISTICS OF THE VAGINAL MICROBIOTA, CERVICAL AND UTERINE FLORA IN WOMEN WITH THE PAST HISTORY OF SEXUALLY TRANSMITTED INFECTIONS

The aim: To identify the characteristics of the vaginal microbiota, cervical and uterine flora in women with the past history of sexually transmitted infections. Materials and methods: A prospective study and the analysis of the vaginal microbiota, cervical and uterine flora were conducted in 96 women of reproductive age with infertility after the past history of STIs, who planned to get pregnant using ART. Together they made up the group I (main group) and the CG included 30 women of reproductive age, who planned pregnancy without a compromised reproductive history. Results: Nonspecific vulvovaginitis (χ2 = 31.6; p <0.001) was diagnosed in 63 (63.6%) patients of the group I, vulvovaginal candidiasis - in 17 (17.7%). Lactobacilli in a vaginal discharge in representatives of the CG and group I - 96.7% and 29.1%, respectively (χ2 = 20.3; p <0.001). Opportunistic pathogens, BV-associated microorganisms and obligate anaerobes in the next titers: 10x5 CFU/ml and higher, CG < 10x3 CFU/ml were found in 68 (70.8%) women of the group I. N. gonorrhoeae was detected in 2 (2.1%) patients of the group I. An intense leukemoid reaction - in 59 (61.5%) women of the group I. The rate of cervical contamination with these pathogens ranged from 10x3 to 10x4 CFU/ml in 35 (36.5%) women of the group I, in 61 (63.5%) - titers of opportunistic pathogens were > 10x4 CFU/ml. Pathogenic bacteria of the cervical canal, represented by obligate anaerobes, was detected in 70 (72.9%) cases, where 11 (11.4%) patients were diagnosed with Chlamydia trachomatis, 2 (2.1%) - N.gonorrhoeae. Chlamydia trachomatis and Mycoplasma genitalium were registered in 11 (11.5%) and 19 (19.8%) cases, respectively, and were not detected in controls. Ureaplasma urealyticum in the cervical canal outnumbered the diagnostic level in women: 17.7% - group I and 6.7% - CG, respectively (χ2 = 7.9; p <0.01). N.gonorrhoeae and Trich. vaginalis were detected in 2.1% and 6.25% of women in the group I, respectively. Persistent urogenital infection - the combination of opportunistic and common pathogens - prevailed in 59 (60.2%). Associations of obligate anaerobes and Chlamydia trachomatis were found in 69 (71.8%) of them, microaerophiles - in 29 (30.2%), the combination of various species of opportunistic pathogens - in 14 (14.6%); the growth of monocultures of opportunistic pathogens, in titers coming to 106-108, was recognized in 19 (19.8%). The growth of monoculture, represented by group B Streptococcus was detected in 8 (8.3%) cases, Enterococcus faecalis - in 12 (12.5%), Mycoplasma genitalium - in 17 (17.7%). The analysis of PCR test results enabled to detect associations of different species of viruses with Myco- and Ureaplasma, Chlamydia in 23 (23.9%) patients of the group I. What should be noted is the predominance of Herpes simplex over CMV infection: 7 (7.3%) and 2 (2.1%), respectively (p <0.05). Conclusions: The predominance of the mixed microbiota, represented by various associations of opportunistic and common pathogens, was identified in infertile women with the past history of STIs as a result of microbial culturing of the samples from the uterine cavity. Chronic inflammation in endometrium is caused by a persistent viral-bacterial infection in the uterine cavity, which differs in the species composition from the microbiota of the lower genital tract.

Bacterial contamination of forehead skin and surgical mask in aerosol-producing dental treatment

ABSTRACT Background Bacterial contamination of dental professionals’ facial skin and protective equipment from treatment-related aerosols and droplets are poorly studied. Methods This prospective study analyzed samples from 67 consecutive aerosol-producing dental treatments. Sterile nylon swabs served to collect samples from dental professionals’ foreheads before and after exposure. Contact samples were obtained from used surgical masks. Samples were incubated on agar under aerobic and anaerobic conditions. Bacteria were classified by MALDI-TOF mass spectrometry. We determined the frequencies of obligate and facultative oral bacteria and scored bacterial growth (0: none; 1: < 100 colonies; 2: >100 colonies; 3: dense). Results Bacteria were detected in 95% of skin-swab and 76% of mask samples. Median bacterial scores were 2 for forehead samples before and after treatment, and 1 for masks. Obligate and facultative oral bacteria were more frequent (6% and 30%) in samples from exposed forehead skin, which also showed increased bacterial scores (28%). 5% of samples contained methicillin-sensitive Staphylococcus aureus; 3% contained obligate anaerobes. Conclusion Exposed forehead skin was significantly less contaminated with obligate oral bacteria than expected based on surgical mask findings. Exposed forehead skin showed increased contamination attributable to aerosol-producing procedures. The forehead’s physiological skin microbiota may offer some protection against bacterial contamination.

Microbiological profile of aerobic and anaerobic bacteria and its clinical significance in antibiotic sensitivity of odontogenic space infection: A prospective study of 5 years.

Introduction:Odontogenic infections are mixed aerobic-anaerobic microbial flora. Infections caused by anaerobic bacteria are serious and life-threatening. The microbial specificity in odontogenic infections is technique sensitive depending on the sampling and culturing of specimens.Materials and Methods:A prospective study was carried out on 100 consecutive cases of odontogenic infections treated at our institute over a period of 5 years by surgical intervention and intravenous antibiotics. This study evaluates the pathogenic potential and virulence factors of aerobes and anaerobes as well as its synergistic interrelations with other infectious flora, by culturing of specimens and testing antibiotic sensitivity in standard microbiological methodology in correlation with patient demographic factors.Results:Of the 100 patients of odontogenic space infection, males were more affected, between third and fourth decades. Caries is the most common etiology with involvement of mandibular molars. Submandibular and buccal space is commonly involved. The most common microorganisms isolated being Staphylococcus aureus and Streptococcus viridans are facultative anaerobes which belong to aerobes and Peptostreptococcus predominated among obligate anaerobes. The empirical antibiotic regimen followed is amoxicillin plus clavulanic acid with Metronidazole, followed by surgical treatment. Clindamycin was preferred as the second line of choice in patients resistance to penicillin drugs with comparable efficacy in it.Conclusion:Our study expanded the knowledge base of the microbial flora associated with odontogenic infections, with special reference to anaerobes. Successful management of odontogenic space infection lies in decompression, removal of etiological factors, and also in selecting appropriate antimicrobial therapy depending on microbial flora isolated, for recovery of patients and preventing complications associated with fascial space infection.

Synthetic Biology Medicine and Bacteria-Based Cancer Therapeutics.

Spontaneous tumor regression following bacterial infection has been observed for hundreds of years. These observations along with anecdotal medical findings in 1890s led to the development of Coley's "toxins," consisting of killed Streptococcus pyogenes and Serratia marcescens bacteria, as the first cancer immunotherapy. The use of this approach, however, was not widely accepted at the time especially after the introduction of radiation therapy as a treatment for cancer in the early 1900s. Over the last 30-40years there has been renewed interest in the use of bacteria to treat human solid tumors. This is based on the observation that various nonpathogenic anaerobic bacteria can infiltrate and replicate within solid tumors when given intravenously. Bacteria tested as potential anticancer agents include the Gram-positive obligate anaerobes Bifidobacterium and Clostridium, as well as the gram-negative facultative anaerobe Salmonella. Recent advances in synthetic biology and clinical success in cancer immunotherapy provide renewed momentum for developing bacteria-based cancer immunotherapy for cancer treatment and should allow greater potential for the development of novel therapeutic approaches for this devastating disease.

Тhe features of the microbial spectrum of obligate anaerobes in purulent phlegmons of odontogenic nature in maxillofacial pathology

Тhe features of the microbial spectrum of obligate anaerobes in purulent phlegmons of odontogenic nature in maxillofacial pathology

Enzyme functionalized microgels enable precise regulation of dissolved oxygen and anaerobe culture.

Anaerobes are a major constituent of the gut microbiome and profoundly influence the overall health of humans. However, the lack of a simple, cost-effective, and scalable system that mimics the anaerobic conditions of the human gut is hindering research on the gut microbiome and the development of therapeutics. Here, we address this gap by using glucose oxidase and catalase containing gelatin microparticles (GOx-CAT-GMPs) to precisely regulate dissolved oxygen concentration [O2] via GOx-mediated consumption of oxygen. Fluorescence images generated using conjugated polymer afterglow nanoparticles showed that [O2] can be tuned from 257.9 ​± ​6.2 to 0.0 ​± ​4.0 ​μM using GOx-CAT-GMPs. Moreover, when the obligate anaerobe Bacteroides thetaiotaomicron was inoculated in media containing GOx-CAT-GMPs, bacterial growth under ambient oxygen was comparable to control conditions in an anaerobic chamber (5.4 ​× ​105 and 8.8 ​× ​105 colony forming units mL−1, respectively). Finally, incorporating GOx-CAT-GMPs into a bioreactor that permitted continuous radial diffusion of oxygen and glucose generated a gut-mimetic [O2] gradient of 132.4 ​± ​2.6 ​μM in the outer ring of the reactor to 7.9 ​± ​1.7 ​μM at the core. Collectively, these results indicate that GOx-CAT-GMPs are highly effective oxygen-regulating materials. These materials can potentially be leveraged to advance gut microbiome research and fecal microbiota transplantation, particularly in low-resource settings.

723. Epidemiology, Risk Factors, and Treatment Considerations for Pyogenic Liver Abscess (PLA) in the Calgary Health Zone (CHZ) Revisited: A Population-Based Study

BackgroundPLA is a significant cause of morbidity and mortality. However, its epidemiology and outcomes have not been recently evaluated in the CHZ. Understanding current trends will help guide management.MethodsIn this population-based study, we evaluated epidemiology, risk factors, and treatment of patients with PLA in the CHZ. CHZ residents aged ≥ 20 years diagnosed with PLA in 2015-2017 were included. Charts were reviewed for demographics and clinical outcomes. Multivariate logistic regression was used to determine factors associated with 30-day mortality. Findings were compared to a previous assessment of PLA in the CHZ from 1999-2003 (Kaplan et al., 2004).ResultsA total of 136 patients with PLA were identified, representing an annual incidence rate of 3.7 cases per 100,000 population. Compared to 1999-2003, incidence of PLA was increased (2.3 per 100,000; p< 0.01) but mortality was similar (1999-2003: 0.22 per 100,000 vs. 2015-2017: 0.26 per 100,000; p=0.6). The most common culprit organisms were Streptococcus anginosus group (40%), Klebsiella species (25%), Escherichia coli (18%), and obligate anaerobes (16%). Pathogen prevalence was similar to the prior cohort. Compared to 1999-2003, antibiotic resistant organisms were more frequent (8% vs 1%, p=0.04). In our cohort, liver aspirations were less frequent (p=0.02) but aspirate culture was more often positive (p< 0.01). The median duration of intravenous antibiotic therapy was longer compared to previous (2015-2017: 23 days (IQR 9-38) vs. 1999-2003: 17 days (IQR 10-29); p=0.001). Similarly, the total duration of antibiotic therapy was longer (2015-2017: 42 days (IQR 25-65) vs. 1999-2003: 31 days (IQR 18-45); p< 0.001). Thirty-day mortality from admission was 7% and did not differ amongst cohorts. Risk factors are shown in Table-1.Table-1: Risk factors for 30-day mortality in PLA ConclusionIncidence of PLA in the CHZ is rising with more antimicrobial resistance. Diagnostic liver aspirations are less frequent. Antibiotic durations are longer with no reduction in mortality. Understanding changing trends is valuable in directing future care. Encouraging liver aspirations to obtain a microbiologic diagnosis, especially with increasing resistance, is crucial. Considering shorter antibiotic durations in light of stable mortality warrants further exploration.Disclosures All Authors: No reported disclosures

Herbal Sealers in Endodontics – A Systematic Review

Root canal infections usually occur due to many micro-organisms, among which most frequent are the obligatory anaerobes. One of the predominantly found microbes is Candida albicans that requires special attention. Herbs have and are being used for health ailments and avoiding diseases that include epidemics for decades. A lot of plants are used as Phytomedicines in the dental profession because they have various biological and antimicrobial effects. Various irritants are used such as NaOCl, Chlorhexidine, hydrogen peroxide, ethylenediaminetetraacetic acid (EDTA), citric acid etc. to eradicate microbes. However, these irrigants may have several disadvantages. In Endodontics, plants and their extract can be used as irrigant and intracanal medicament to prevent the potential side effects caused by conventional chemical agents. Less toxic herbal products are being used since ancient era, and they are Triphala, Morinda citrofolia, Propolis, Azadirachta indica, Carvacrol, Green tea, Orange oil, tea tree oil, Arctium lappa, Garlic extract etc. Most commonly used are Triphala, Morinda citrofolia, Propolis, Azadirachta indica, Green tea, Garlic extract. Such herbal preparations are derived from the roots, leaves, seeds, stems and flowers of medicinal plants. This systematic review aims to enlighten and focus on various herbal products that can be used in endodontics to eradicate the root canal infection and to create the environment necessary for periapical healing. This is essential for successful Root canal treatment.

Impact of Preoperative Occult-Bacterial Translocation on Surgical Site Infection in Patients Undergoing Pancreatoduodenectomy

Occult-bacterial translocation (O-BT) has been reported as the condition in which microorganisms are detected in blood or lymph nodes by a highly sensitive method. However, the clinical impact of preoperative O-BT on postoperative complication is unclear. A prospective observational study with patients undergoing pancreatoduodenectomy for periampullary diseases was conducted. Blood samples were collected immediately after induction of anesthesia. The status of O-BT was investigated using bacterium-specific ribosomal RNA-targeted reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). The impact of O-BT on surgical site infection (SSI) was analyzed. A total of 155 patients were included. The positive rate in preoperative blood samples detected by RT-qPCR was significantly higher than that obtained by the culture method (32 of 155 vs 4 of 155, p < 0.001). Preoperative blood samples were contaminated with 1.0 to 19.2 bacterial cells/mL in positive patients, and 30 of the 41 detected microorganisms were obligate anaerobes. No differences in preoperative factors were observed between patients with positive and negative RT-qPCR results. The incidence of any SSI was significantly higher in patients with contaminated preoperative blood (≥1.2 bacterial cells/mL) than in other patients (14 of 27 vs 35 of 128, p= 0.013). Multivariable analysis indicated that contaminated preoperative blood was identified as one of the independent risk factors for SSI (odds ratio 2.71, 95% CI 1.04 to 7.24, p= 0.041). O-BT, predominantly with obligate anaerobes, was commonly observed in preoperative blood samples. In addition to the previously known risk factors, O-BT may be one of the risk factors for SSI after pancreatoduodenectomy.

Artificial consortium demonstrates emergent properties of enhanced cellulosic-sugar degradation and biofuel synthesis

Planktonic cultures, of a rationally designed consortium, demonstrated emergent properties that exceeded the sums of monoculture properties, including a >200% increase in cellobiose catabolism, a >100% increase in glycerol catabolism, a >800% increase in ethanol production, and a >120% increase in biomass productivity. The consortium was designed to have a primary and secondary-resource specialist that used crossfeeding with a positive feedback mechanism, division of labor, and nutrient and energy transfer via necromass catabolism. The primary resource specialist was Clostridium phytofermentans (a.k.a. Lachnoclostridium phytofermentans), a cellulolytic, obligate anaerobe. The secondary-resource specialist was Escherichia coli, a versatile, facultative anaerobe, which can ferment glycerol and byproducts of cellobiose catabolism. The consortium also demonstrated emergent properties of enhanced biomass accumulation when grown as biofilms, which created high cell density communities with gradients of species along the vertical axis. Consortium biofilms were robust to oxic perturbations with E. coli consuming O2, creating an anoxic environment for C. phytofermentans. Anoxic/oxic cycling further enhanced biomass productivity of the biofilm consortium, increasing biomass accumulation ~250% over the sum of the monoculture biofilms. Consortium emergent properties were credited to several synergistic mechanisms. E. coli consumed inhibitory byproducts from cellobiose catabolism, driving higher C. phytofermentans growth and higher cellulolytic enzyme production, which in turn provided more substrate for E. coli. E. coli necromass enhanced C. phytofermentans growth while C. phytofermentans necromass aided E. coli growth via the release of peptides and amino acids, respectively. In aggregate, temporal cycling of necromass constituents increased flux of cellulose-derived resources through the consortium. The study establishes a consortia-based, bioprocessing strategy built on naturally occurring interactions for improved conversion of cellulose-derived sugars into bioproducts.

Professor Daniel I.C. Wang: A Legacy of Education, Innovation, Publication, and Leadership.

Professor Daniel I.C. Wang: A Legacy of Education, Innovation, Publication, and Leadership.

The impact of fixed orthodontic appliances on oral microbiome dynamics in Japanese patients

Fixed orthodontic appliances are common and effective tools to treat malocclusion. Adverse effects of these appliances, such as dental caries and periodontitis, may be associated with alteration of the microbiome. This study investigated the impact of these appliances on the dynamics of the oral microbiome. Seventy-one patients were selected. Supragingival plaque samples were collected before placement (T0) and six months after placement (T1). Saliva samples were collected at T0 and T1, and then when appliance removal (T2). Microbial DNA was analyzed by 16S rRNA meta-sequencing. The diversity analysis indicated dynamic changes in the structure of the oral microbiome. Taxonomic analysis at phylum level showed a significant increase in Bacteroidetes and Saccharibacteria (formally TM7) and decrease in Proteobacteria and Actinobacteria over time, in both plaque and saliva. Genus level analysis of relative abundance indicated a significant increase in anaerobic and facultative anaerobes in both plaque and saliva. Fixed orthodontic appliances induced measurable changes in the oral microbiome. This was characterized by an increase in relative abundance of obligate anaerobes, including periodontal pathogens. It can be concluded that this dysbiosis induced by fixed orthodontic appliances is likely to represent a transitional stage in the shift in microbiome from healthy to periodontitis.

Clinical and laboratory evaluation of the secnidazole and clindamycin effects on bacterial vaginosis in the women of reproductive age

Bacterial vaginosis is the most common among all infectious diseases of the female reproductive system. Recently the clinical signs of the disease have become increasingly weakening and frequently are appearing asymptomatic carriers, atypical and delayed forms. According to various authors it accounts for 20 to 60% of all vulvovaginal infections of the lower female reproductive organs. Currently used medical drug complexes are not always effective and therefore there is a need of search and implementation of new and effective methods.Objective. The aim of this study was to develop effective criteria for assessing the microbiological characteristics of infectious interactions for bacterial vaginosis in order to increase the effectiveness of diagnosis, treatment and prevention of this disease. For the treatment of bacterial vaginosis were used tablets of secnidazole 0.5 – 1 tablet 2 times for 2 days orally during menstruation.Material and methods. It was conducted a comprehensive survey of 40 (10) women aged 21-45 years who had chronic bacterial vaginosis as the main diagnosis. All women were subjected to complex examination using the pH determination of the vaginal content reaction and aminotest (reaction with 10% potassium hydroxide solution). Laboratory studies included: microscopy of vaginal smear according to Gram in the modification of Kopeloff, bacteriological culture on nutrient media to determine facultative and obligate anaerobic bacterias. Clinical laboratory evaluation was performed after verification of the diagnosis of bacterial vaginosis and one month after treatment with secnidazole and clindamycin.Results. After secnidazole and clindamycin treatment in the women with bacterial vaginosis the clinical symptoms of the disease disappeared and was observed complete recovery. In all women of 2 group lactobacilli were isolated in the form of an association in high concentrations 106 -107 with high protective ability as in women with normocenosis of the vagina. Facultative anaerobes after the use of the proposed therapy have always been found in monoculture, the degree of vaginal insemination was 104 or less CFU/ml. The same tendency was observed for obligate anaerobes after using the proposed treatment. Their composition and concentration approached the limit of the norm variant.Conclusion. Analysis of the treatment of women with bacterial vaginosis allows us to conclude that the use of the proposed therapy enables recovery of vaginal normocenosis with a few men's concentration of lactobacilli 106 and this, in turn, requires etiologically and pathogenetically based diagnostic, therapeutic and prophylactic measures.

Environmental factors and periodontal microbiome.

Periodontal diseases are chronic inflammatory, multifactorial diseases where the major triggering factors for disease onset are bacteria and their toxins, but the major part of tissue destruction occurs as a result of host response towards the periodontal microbiome. Periodontal microbiome consists of a wide range of microorganisms including obligate and facultative anaerobes. In health, there is a dynamic balance between the host, environment, and the microbiome. Environmental factors, mainly tobacco smoking and psychological stress, disrupt the symbiotic relationship. Tobacco smoke and its components alter the bacterial surface and functions such as growth. Psychological stressors and stress hormones may affect the outcome of an infection by changing the virulence factors and/or host response. This review aims to provide currently available data on the effects of the major environmental factors on the periodontal microbiome.