Anaerobic Bacteria Research Articles

Leuconostoc koreense sp. nov., isolated from kimchi, a fermented vegetable.

The novel strain CBA3628T was isolated from kimchi, a Korean fermented vegetable. CBA3628T is a cocci-shaped, Gram-stain-positive, catalase- and oxidase-negative and facultatively anaerobic bacterium. The results of phylogenetic analysis based on 16S rRNA gene sequencing indicated that CBA3628T represented a member of the genus Leuconostoc of the family Leuconostocaceae. CBA3628T has a circular chromosomal genome and three plasmids of 1 864 558 bp (37% DNA G+C content), containing 1,887 genes, 1,762 predicted protein-coding genes, 4 complete rRNA loci and 70 tRNA genes. The cells were non-haemolytic, non-motile and non-spore forming. The optimal growth of CBA3628T occurred at 30 °C, pH 6.0 and with 0-2% (w/v) NaCl. The major polar lipids of CBA3628T were diphosphatidylglycerol and phosphatidylglycerol. The major fatty acids (>10%) of CBA3628T were C16 : 0, C20 : 0 and C19 : 0 cyclo ω8c. CBA3628T contained A3α-type peptidoglycans. CBA3628T was most closely related to Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293T, L. mesenteroides subsp. dextranicum DSM 20484T and L. suionicum DSM 20241T with 99.52% 16S rRNA gene sequence similarity. However, the average nucleotide identities of 91.9%, 91.7% and 91.1% and the digital DNA-DNA hybridisation values of 45.6%, 45.4% and 45.4% indicated that the novel isolate represented a distinct species. Phylogenetic analyses of both the 16S rRNA gene and genome sequences revealed that CBA3628T formed a distinct phylogenetic lineage within the genus Leuconostoc and was most closely related to Leuconostoc litchii MB7T. The ANI and dDDH values between CBA3628T and L. litchii MB7T were 84.9 and 22.8%, respectively. Functional genes belonging to COG categories E, J and K were enriched in the genome of CBA3628T (>7.9%). On the basis of its physiological, chemotaxonomic, phylogenetic and genomic properties, strain CBA3628T represents a novel species from the genus Leuconostoc, for which we propose the name Leuconostoc koreense sp. nov., with the type strain CBA3628T (= KACC 23049T = DSM 116836T).

Clinical Validation and Comparison of Bacterial Vaginosis Detection

Abstract Introduction/Objective Bacterial vaginosis (BV) is considered a top reason for women’s gynecological visits, causing symptoms such as vaginal discharge, foul odor, itching, and burning associated with the alteration of the normal vaginal microbiome. It is often presented as a decrease in Lactobacillus spp. and an increase in anaerobic organisms such as Gardnerella vaginalis and Atopobium vaginae. In response to the demand for more automated and less subjective testing, molecular methods have recently been developed to aid in BV testing. The objectives of this study are to validate and compare the molecular Aptima® Bacterial Vaginosis Assay by Hologic® to the established BV Screen via a Gram stained vaginal smear graded through Nugent scoring at RUSH University Medical Center in Chicago, IL and perform a cost analysis between the testing methods. Methods/Case Report Samples of known BV value were tested on the Panther® instrument to validate the Aptima® Bacterial Vaginosis Assay for accuracy and precision. Clinical samples of vaginal swabs were used to make a Gram stained BV screen for Nugent scoring, then afterwards were placed into Hologic Multitest Aptima® probes for molecular testing on the Panther® instrument. Nugent scoring was performed blind by the molecular test. Molecular results of negative, positive, and invalid were then compared to the Nugent scores: scores of 0-3 for negative/normal vaginal flora, 7-10 for positive BV, and 4-6 for intermediate/altered scores were screened for discrepancy. Results (if a Case Study enter NA) The Aptima® BV Assay tested 52 known samples with 97% accuracy and 100% precision. A total of 80 clinical samples of vaginal swabs used for Gram stained BV screens were run on the Aptima® BV Assay; 61 provided conclusive data for comparative analysis. When compared to the original Nugent scores, the positive percent agreement (PPA) was 77.0% and negative percent agreement (NPA) was 92.9%. Conclusion The Aptima® BV Assay proved to be both accurate and precise in its validation testing. Clinically, it was able to screen for BV in vaginal samples with a good percent agreement to Gram stained BV screens. Further testing of additional clinical samples are to be done to continue analysis. Although the supplies needed to perform a Gram stain cost less than molecular testing, the reimbursement payment for molecular testing is much greater and overall reduces employee time costs for performing the test, making it the more cost effective choice for the laboratory.

Microbiological Quality Assessment of Some Commercially Available Breads.

Bread is a staple, energy-rich food for people of all ages, so quality is important to consumers. In our region, most of the commercially available bread, whether packaged or unpackaged, is produced by local bakeries, so monitoring microbial levels and the types of microbes present on bread can help to draw attention to protect the final product. It can also help to ensure the food safety, quality, and shelf life of bread. The freshly baked product is microbiologically sterile. Post-process contamination affects the microbial load of bread. In this study, the microbial load of 30 different commercial bread crumbs and crusts was determined. The different types of bread with different compositions were analyzed for total viable bacteria, Escherichia coli, Staphylococcus aureus, aerobic and anaerobic spore-forming bacteria, and culturable microscopic fungi. The K-means clustering algorithm was used to cluster the different types of bread based on the number of aerobic mesophilic bacteria. Significant differences (p < 0.05) were found in the total viable bacterial count for bread crusts and crumbs. The bacterial count of bread varied between 10.00 ± 0.00-395.00 ± 52.4 CFU/g for bread crusts and 10.00 ± 0.0-310.67 ± 94 CFU/g for bread crumbs. The results of 16S rDNA sequence analysis showed that the most frequently occurring bacterial species belonged to the genus Bacillus, but species of the genus Staphylococcus were also present. Chryseobacterium spp. predominated on multigrain bread, Marinilactobacillus spp. on rustic potato bread, and Staphylococcus warneri on sliced brown potato bread. The results contribute to a better understanding of the microbial dynamics in locally produced breads from the Eastern Carpathians of Transylvania, with the aim of improving food safety, quality control, and consumer protection.

Comparison of the antibacterial activity of six medicinal plants, sodium hypochlorite, and chlorhexidine against enterococcus faecalis (In vitro study)

Enterococcus faecalis is a gram-positive, facultative anaerobic bacterium recognized for its resistance to various antimicrobial agents. This organism is associated with the failure of endodontic treatments, even when potent antimicrobial irrigants are employed. Numerous medicinal plants have demonstrated antimicrobial properties that could be potentially effective against this bacterium.To evaluate the antibacterial properties of six medicinal plants in comparison to sodium hypochlorite and chlorhexidine against E. faecalis.Antibacterial susceptibility tests against E. faecalis (ATCC 29212) were performed for 200 mg/ml ethanolic extracts of Acacia Senegal, Capparis decidua, Capparis micracantha, Acacia nilotica/ Adansonia, Dobera glabra, and Moringa oleifera by Agar Disc Diffusion method. Chlorhexidine 0.2% and Sodium hypochlorite 1% were used as positive controls, and ethanol 20% as a negative control. The diameters of the inhibition zones were measured. Acacia nilotica/adansonii leaves showed the largest inhibition zone diameter against E. faecalis. It displayed a significantly greater inhibitory effect against E. faecalis than Acacia Senegal (p-value =0.005), Capparis decidua (p-value =0.02), Capparis micracantha branches (p-value =0.000), Dobera glabra leaves (p-value =0.008), and Moringa olifera leaves (p-value =0.000).Acacia nilotica leaves displayed a similar inhibition zone diameter against E. faecalis as chlorhexidine gluconate 0.2%, but it showed no statistical significance. Acacia nilotica leaves (L) and pods (P), as well as Dobera glabra branches (B), displayed a larger inhibition zone diameter against E. faecalis than Sodium hypochlorite 1%, but with no statistical significance. The leaves of Acacia nilotica exhibit the most potent antibacterial properties against E. faecalis when compared to other plants parts. They outperform the antibacterial effectiveness of 1% sodium hypochlorite and demonstrate a similar antibacterial impact to that of 0.2% chlorhexidine. Therefore, Acacia nilotica leaves could serve as an ideal irrigant potentially substituting the chemical options.

The potential of alkaline tolerant microbial consortia for textile wastewater treatment under integrated anaerobic/aerobic conditions: Performance evaluation and microbial community analysis

Sequential anaerobic/aerobic (A/O) treatment conditions for textile wastewater (WW) are more effective than conventional biological treatment. Anaerobic treatment is essential because anaerobic microbes can first break down complex and recalcitrant compounds, which are difficult to degrade under aerobic conditions. The simpler, more degradable compounds are then further broken down by aerobic microbes. This study aimed to evaluate the performance of a sequential A/O treatment process using a pilot-scale reactor to treat real textile WW and to characterize reactor and inoculum microbial community structures. The reactors were inoculated with microbial consortia originating from a diverse alkaliphilic soda lake in the Ethiopian Rift Valley. The WW test parameters were used to evaluate the performance of the treatment process. At steady state, the removal efficiencies were 97 % for dye, 86 % for Chemical Oxygen Demand (COD), and 93 % for Total Kjeldahl Nitrogen (TKN). Amplicon sequencing revealed that Firmicutes, Proteobacteria, and Actinobacteria were the dominant phyla in all the samples. Uncategorized microorganisms, followed by Alkalibacterium, Bifidobacterium, and Clostridium were the most abundant taxon in all the samples. The microbial community detected during the treatment process was not abundant in the inoculum originating from Lake Chitu, suggesting that the communities likely originated from textile WW. The textile WW treated with the integrated A/O process effectively degraded dyes, and the inoculated microbes demonstrated resistance to the toxic chemical composition of the WW. The integrated treatment process, along with the alkaliphilic microbial consortia, has proven to be practical for treating textile WW, offering valuable insights for field-scale applications.

Current issues of using metronidazole in clinical practice. Effects and directions of clinical application

Metronidazole is an important drug in clinical and outpatient practice due to its broad antibacterial and antiprotozoal properties. Metronidazole is effective against anaerobic bacteria and some protozoa such as Trichomonas vaginalis and Giardia lamblia. This makes it indispensable in the treatment of infections of various etiologies. The review article contains current information about the clinical pharmacology of metronidazole and its place in the pharmacotherapy of infectious diseases. General and specific issues of the use of metronidazole in the practice of GPs, surgeons, obstetrician-gynecologists, and other specialists are considered. Information is provided on the possibilities and indications for the use of metronidazole in the eradication of Helicobacter pylori, in radiation therapy for cancer patients, dermatovenereology, dentistry, treatment of protozoal infections, as well as in alcoholism. Metronidazole is often used in combination with other antibiotics to enhance the antimicrobial effect, especially in cases of mixed infections or when it is necessary to cover a wider range of pathogens. In surgical practice, metronidazole is used to prevent infectious complications after operations on the abdominal and pelvic organs, where the risk of anaerobic infection is high. In an environment of increasing antibiotic resistance, metronidazole remains an effective treatment against many anaerobic pathogens, highlighting its place in modern practice.

Empirical antibiotic therapy for sepsis: save the anaerobic microbiota.

Antibiotics are fundamental in sepsis management; however, the optimal empirical treatment remains debated. Despite anaerobes rarely being the causative pathogen of sepsis, antibiotics targeting them are frequently used, which might lead to unintended consequences. Multiple studies have shown that depletion of commensal anaerobic gut microbes by anti-anaerobic antibiotics influences systemic immunity and is associated with increased mortality in patients with sepsis. However, this knowledge has not yet been translated into clinical practice. When considering empirical coverage of anaerobic pathogens in sepsis, most physicians advocate for a better-safe-than-sorry approach. In this Viewpoint, we argue that anti-anaerobic antibiotics could often result in being sorry rather than safe. We provide an overview of the limited necessity of anaerobic coverage and the potential detrimental effects of anaerobic depletion in sepsis. We aim to raise anaerobic awareness to reduce the unnecessary use of anti-anaerobic antibiotics in empirical sepsis treatment and improve patient outcomes.

Effects of four-week lasting aerobic treadmill training on hepatic injury biomarkers, oxidative stress parameters, metabolic enzymes activities and histological characteristics in liver tissue of hyperhomocysteinemic rats.

Disruptions in homocysteine (Hcy) metabolism may increase the liver's susceptibility to developing conditions such as alcoholic liver disease, viral hepatitis, hepatocellular carcinoma (HCC), and cirrhosis. The aim of this study was to examine effects of aerobic treadmill training on hepatic injury biomarkers in sera, oxidative stress parameters, the activity of metabolic enzymes, and histological characteristics in the liver tissue of rats with experimentally induced hyperhomocysteinemia. Male Wistar albino rats were divided into four groups (N = 10, per group): C-saline 0.2mL/day sc. 2×/day for 14days + saline 0.5mL ip.1×/day for 28days; H-homocysteine 0.45µmol/g b.w. 2×/day for 14days + saline 0.5mL ip.1×/day for 28days; CPA-saline 0.2mL/day sc. 2×/day for 14days + aerobic treadmill training for 28days; and HPA-homocysteine 0.45µmol/gb.w. 2×/day for 14days + aerobic treadmill training for 28days. The serum albumin concentration was decreased in both physically active (PA) groups compared to sedentary groups. Concentration of malondialdehyde in liver tissue homogenates was lower in both PA groups compared to the H group. The total lactate dehydrogenase and malate dehydrogenase activities were significantly elevated in the HPA group compared to the C and H groups. Activities of aminotransferases in sera samples, and activities of catalase and superoxide dismutase in liver tissue did not significantly differ between groups. No significant histological changes were found in liver tissue in groups. This study demonstrated that aerobic treadmill training can reduce lipid peroxidation in liver tissue under hyperhomocysteinemic conditions, providing a protective effect. However, hyperhomocysteinemia can alter energy metabolism during aerobic exercise, shifting it toward anaerobic pathways and leading to elevated lactate dehydrogenase activity in the liver. Given that conditions like hyperhomocysteinemia are associated with an increased risk of cardiovascular diseases and liver damage, understanding how exercise influences these dynamics could guide therapeutic approaches.

Draft genome of Thermoanaerobacter thermohydrosulfuricus strain AK152, a novel thermophilic and anaerobic bacterium isolated from a hot spring in Iceland.

We present the draft genome of the bacterium Thermoanaerobacter thermohydrosulfuricus strain AK152, a thermophilic, endospore-spore-forming, anaerobe isolated from a hot spring in Grensdalur, in Southwestern Iceland. This assembled genome will lay the foundation for identifying the carboxylic and amino acid fermentation pathways, suggesting biotechnological applications for this strain.

Oxygen exposure decreases the yield of high-molecular-weight DNA from some anaerobic bacteria and bacterial communities during DNA extraction

ObjectivesThe central challenge in third-generation sequencing lies in meeting the requirements for DNA quality (integrity and purity) and quantity. Therefore, novel improvements in DNA extraction methods are needed to satisfy these requirements. We reasoned that in anaerobic microbial communities, the presence of certain strict anaerobes containing oxygen-activated DNase activity might contribute substantially to the poor integrity of extracted metagenomic DNA (or genomic DNA from some pure cultures) if exposed to air. MethodsTo test this hypothesis, we developed an enhanced genomic and metagenomic DNA isolation technique that we applied to a specifically chosen set of both strict and aerotolerant anaerobes, as well as to the hindgut microbiota of a herbivorous marine fish. ResultsConsidering the quality (or degradation) of extracted DNA obtained under anaerobic versus aerobic conditions, we found that DNA extracted aerobically from cells of some strict anaerobes showed more degradation of high molecular weight DNA than analogous preparations under anaerobic conditions. In contrast, with the selected aerotolerant anaerobes, no discernible difference was found between the molecular sizes of DNA extracted aerobically and anaerobically. Metagenomic DNA extracted from the fish hindgut microbiota showed higher yields and better quality under anaerobic conditions compared to aerobic conditions. ConclusionOur study effectively demonstrates the advantages of our improved extraction protocol in anaerobic conditions. This is evident through the improved quality of extracted DNA. Such findings may be valuable for studies, especially metagenomic studies, where the quality and quantity of DNA are crucial for downstream analysis.

The origin of methyl group in methanogen-mediated mercury methylation: From the Wolfe cycle

Methylmercury (MeHg) is a bioaccumulating neurotoxin mainly produced by anaerobic microorganisms, with methanogen being one of the important methylators. A critical aspect for understanding the mechanism for microbial mercury (Hg) methylation is the origin of the methyl group. However, the origin of methyl group in methanogen-mediated Hg methylation remains unclear. This study aims to identify the source of methyl group for MeHg synthesis in methanogens. Our study revealed that Hg methylation in Methanospirillum hungatei JF-1 is closely related to methanogenesis process, according to the results of proteomic study and substrate limitation study. Next, we proved that nearly all methyl group in MeHg derives from the Wolfe cycle in this species, rather than the previously demonstrated acetyl-coenzyme A pathway, based on the results of 13C labeling study. We then proposed the Wolfe cycle-dependent Hg methylation mechanism in this species. Further genome analyses and 13C labeling experiments indicated that the involvement of the Wolfe cycle in Hg methylation is probably a universal feature among Hg-methylating methanogens. These findings reveal a unique Hg methylation mechanism in methanogens. Our study broadens the carbon substrates and controlling factors for MeHg synthesis in the environment, which can inform the prediction of MeHg production potential and remediation strategies for MeHg contamination.

The utilization of N-acetylgalactosamine and its effect on the metabolism of amino acids in Erysipelotrichaceae strain

BackgroundThe metabolism of gut microbiota produces bioactive metabolites that modulate host physiology and promote self-growth. Erysipelotrichaceae is one of the most common anaerobic microorganism families in the gut, which has been discovered to play a vital role in host metabolic disorders and inflammatory diseases. Our previous study found that N-acetylgalactosamine (GalNAc) in caecal content of pigs significantly affected the abundance of Erysipelotrichaceae strains. However, it remains unknown how GalNAc feeding in vitro culture affects the expression levels of genes in the GalNAc metabolic pathway and the concentrations of intermediate metabolites in the Erysipelotrichaceae strain. Whether GalNAc feeding should influence the metabolism of other nutrients, such as amino acids, remains unrevealed.ResultsIn this study, whole-genome sequence, transcriptome, and metabolome data were analyzed to assess the utilization of a Erysipelotrichaceae strain on GalNAc. The results showed the presence of a complete GalNAc catabolism pathway in the genome of this Erysipelotrichaceae strain. GalNAc feeding to this Erysipelotrichaceae strain significantly changed the expression levels of genes involved in glycolysis and tricarboxylic acid (TCA) cycle. Meanwhile, the concentrations of lactate, pyruvate, citrate, succinate and malate from the glycolysis and TCA cycle were significantly increased. In addition, transcriptome analysis indicated that the genes involved in the metabolism of amino acids were affected by GalNAc, including lysA (a gene involved in lysine biosynthesis) that was significantly down-regulated. The intracellular concentrations of 14 amino acids in the Erysipelotrichaceae strain were significantly increased after feeding GalNAc.ConclusionsOur findings comfirmed and extended our previous works that demonstrated the utilization of GalNAc by Erysipelotrichaceae strain, and explained the possible mechanism of GalNAc affecting the abundance of Erysipelotrichaceae strain in vitro.

Fournier’s gangrene in voluminous inguinoscrotal herniation: Case report and review of literature

Introduction: Fournier’s gangrene (FG) is a polymicrobial life-threatening infection that affects perineal region and may extend to genitalia and abdominal wall. Necrotizing fasciitis is a rare condition and its association with large inguinoscrotal hernia even rarer. With high mortality rate, some predisposing factors are diabetes and immunodeficiency. Case presentation: We report a case of a 48-year-old man with Fournier’s gangrene associated with voluminous inguinoscrotal herniation which evolved to hernia sac exposure after debridement. Discussion: FG pathophysiology initiates with a localized infection by a combination of gram positive, gram negative and anaerobic bacteria, and its advancing leads to local inflammatory response, thrombosis, blood flow reduction and ischemia. Diagnosis depends on clinical presentation and image evaluation. Conclusion: FG management has been standard in the literature, however its association with inguinoscrotal hernias have not been considered in guidelines. Early diagnosis and proper clinical and surgical treatment are fundamental to avoid life-threatening complications and morbidities.

Effects of Dietary Quality on Vaginal Microbiome Composition Throughout Pregnancy in a Multi-Ethnic Cohort.

Background: Vaginal Lactobacillus predominance is associated with improved vaginal health and reduced pregnancy complications. Little is known about how dietary quality may improve vaginal microbial composition or about dietary interventions that may promote Lactobacillus abundance. To understand the host factors affecting vaginal microbiota during pregnancy in a multi-ethnic cohort in Hawai`i. We hypothesize that better diet quality improves vaginal microbial composition, as represented by Lactobacillus abundance and depletion of anaerobic organisms. Methods: We compared comprehensive diet quality, as measured by the Healthy Eating Index-2015 (HEI-2015), to taxonomic classifications of bacteria present within the vagina. Participants of the four predominant ethnic groups in Hawai'i (Japanese, Filipino, Non-Hispanic White and Native Hawaiian) completed Quantitative Food Frequency Questionnaires (QFFQs) and collected vaginal swabs during each trimester. 16s rRNA amplicon sequencing (V2-V9 regions) was performed on vaginal samples. HEI-2015 scores and macro- and micronutrient intake were compared with the predominant species present using the Mann-Whitney-U test, PERMANOVA, and the Pearson correlation coefficient. A mixed-effects logistics regression model was used to predict the depletion of Lactobacillus species while accounting for confounding demographic factors. Results: Matched, longitudinal data for 40 participants demonstrated three predominant Lactobacillus species: L. crispatus, L. iners, and L. gasseri, with another subset of samples with anaerobic abundance. (Primarily, Atopobium vaginae, Prevotella, and Gardnerella vaginalis.) Non-Hispanic White participants had lower amounts of Lactobacillus iners compared to other racial and ethnic groups. HEI scores correlated with the chao index and observed species number primarily in the first trimester (r = 0.25, p < 0.05). Greater carbohydrate intake was associated with a higher abundance of L. crispatus, while lower carbohydrate intake trended towards more L. iners (0.056) and anaerobic species. Conclusions: Increased carbohydrate consumption and improved diet quality may be associated with beneficial vaginal microbial composition in pregnancy.

Phenotypic and Genomic Characterization of a Sulfate-Reducing Bacterium Pseudodesulfovibrio methanolicus sp. nov. Isolated from a Petroleum Reservoir in Russia.

The search for the microorganisms responsible for sulfide formation and corrosion of steel equipment in the oil fields of Tatarstan (Russia) resulted in the isolation of a new halotolerant strictly anaerobic sulfate-reducing bacterium, strain 5S69T. The cells were motile curved Gram-negative rods. Optimal growth was observed in the presence of 2.0-4.0% (w/v) NaCl, at pH 6.5, and at 23-28 °C under sulfate-reducing conditions. The isolate was capable of chemoorganotrophic growth with sulfate and other sulfoxides as electron acceptors, resulting in sulfide formation; and of pyruvate fermentation resulting in formation of H2 and acetate. The strain utilized lactate, pyruvate, ethanol, methanol, fumarate, and fructose, as well as H2/CO2/acetate for sulfate reduction. The genome size of the type strain 5S69T was 4.16 Mb with a G + C content of 63.0 mol%. On the basis of unique physiological properties and results of the 16S rRNA gene-based phylogenetic analysis, phylogenomic analysis of the 120 conserved single copy proteins and genomic indexes (ANI, AAI, and dDDH), assigning the type strain 5S69T ((VKM B-3653T = KCTC 25499T) to a new species within the genus Pseudodesulfovibrio, is suggested, with the proposed name Pseudodesulfovibrio methanolicus sp. nov. Genome analysis of the new isolate showed several genes involved in sulfate reduction and its sulfide-producing potential in oil fields with high saline formation water.

Differentiation of the Anammox core microbiome: Unraveling the evolutionary impetus of scalable gene flow

Anaerobic ammonium oxidation bacteria (AAOB), distinguished by their unique autotrophic nitrogen metabolism, hold pivotal positions in the global nitrogen cycle and environmental biotechnologies. However, the ecophysiology and evolution of AAOB remain poorly understood, attributed to the absence of monocultures. Hence, a comprehensive elucidation of the AAOB-dominated core microbiome, anammox core, is imperative to further completing the theory of engineered nitrogen removal and ecological roles of anammox. Performing taxonomic and phylogenetic analyses on collected genome repertoires, we show here that Candidatus Brocadia and Candidatus Kuenenia possesses a more compact core than Candidatus Jettenia, which partly explains why the latter has a less common ecological presence. Evidence of gene flow is particularly striking in functions related to biosynthesis and oxygen detoxification, underscoring the evolutionary forces driving lineage and core differentiation. Furthermore, CRISPR spacer traceback of the AAOB metagenome-assembled genomes (MAGs) reveals a series of genetic traces for the concealed phages. By reconceptualizing the functional divergence of AAOB with the historical role of phages, we ultimately propose a coevolutionary framework to understand the evolutionary trajectory of anammox microecology. The discoveries provided in this study offer new insights into understanding the evolution of AAOB and the ecology of anammox.

Vaginal microbiome of women with premature ovarian insufficiency: a descriptive cross-sectional study

Objective This study aimed to describe the vaginal microbiome of women with premature ovarian insufficiency (POI) receiving systemic hormone therapy (HT). Methods Forty women with POI receiving systemic HT for at least 6 months, who were sexually active, were included in the descriptive cross-sectional study. Vaginal secretion was collected for DNA extraction followed by pyrosequencing of the 16S rRNA. The samples were pooled into phylogenetic groups (Ravel groups I–V). Results Women had mean age of 37.13 (± 7.27) years and POI diagnosis at age 27.90 (± 8.68) years, and a mean HT duration of 8.20 (± 8.73) years. It was observed that 33.4% of the women presented group I flora, with a predominance of Lactobacillus crispatus; 9% group II flora, with a predominance of Lactobacillus gasseri; 33.4% group III flora, with a predominance of Lactobacillus iners; 15.2% group IV flora, with a predominance of anaerobic bacteria; and 9% group V flora, with a predominance of Lactobacillus jensenii. Conclusion Women with POI receiving HT presented a vaginal microbiome with a predominance of lactobacilli in the composition of the vaginal flora, specifically L. crispatus and L. iners when evaluated by molecular biology through pyrosequencing of 16S rRNA.

Utilization of MALDI-TOF MS in the etiological diagnosis of deep-seated anaerobic bacterial infections

PurposeDeep-seated abscesses can be caused by a wide array of bacteria in various anatomical sites, the precise identification of which is crucial for implementing organism-specific treatments which can reduce morbidity and mortality. MALDI-TOF MS is a powerful proteomic method for the swift and accurate identification of anaerobic organisms. The aim of this study was to investigate deep-seated infections by MALDI-TOF MS (in comparison to VITEK®2 ANC ID card and phenotypic biochemical tests) and to determine the susceptibility pattern of identified microorganisms. Materials and methodsA total of 104 samples from patients suspected of deep-seated infections were aseptically collected and subjected to microscopy, aerobic/anaerobic cultures and subsequent identification via MALDI-TOF MS followed by antimicrobial susceptibility testing. Anaerobic bacteria were also identified using the VITEK-2 system and phenotypic biochemical tests. ResultsOut of the 104 samples tested, 41.3 % (43/104) showed positive results, predominantly in pus specimens (88 %). Mixed infections were found in 21 % of the positive cases. Of the 52 organisms identified from positive specimens, 19.2 % (10/52) were obligate anaerobes, with Bacteroides fragilis group being the most prevalent, followed by both Clostridium perfringens and Clostridium sporogenes respectively. Escherichia coli was observed to be the most common facultative anaerobic isolate. All obligate anaerobes were successfully identified to the species level via MALDI-TOF MS. In contrast, the VITEK®2 ANC ID card identified only 40 % (4/10) anaerobic bacteria to the species level. All obligate anaerobic organisms showed 100 % susceptibility to metronidazole, vancomycin and ertapenem. 25 % of the Bacteroides spp. and 50 % of Clostridium perfringens isolates were found to be resistant to clindamycin. ConclusionMALDI-TOF MS proves as a beneficial diagnostic tool for bacterial identification, eliminating the labour-intensive and time consuming conventional microbiological methods. Its accuracy of bacterial detection further helps in combating antibiotic resistance and improving patient outcomes in deep-seated infections.

Growth of sulfate-reducing Desulfobacterota and Bacillota at periodic oxygen stress of 50% air-O2 saturation

BackgroundSulfate-reducing bacteria (SRB) are frequently encountered in anoxic-to-oxic transition zones, where they are transiently exposed to microoxic or even oxic conditions on a regular basis. This can be marine tidal sediments, microbial mats, and freshwater wetlands like peatlands. In the latter, a cryptic but highly active sulfur cycle supports their anaerobic activity. Here, we aimed for a better understanding of how SRB responds to periodically fluctuating redox regimes.ResultsTo mimic these fluctuating redox conditions, a bioreactor was inoculated with peat soil supporting cryptic sulfur cycling and consecutively exposed to oxic (one week) and anoxic (four weeks) phases over a period of > 200 days. SRB affiliated to the genus Desulfosporosinus (Bacillota) and the families Syntrophobacteraceae, Desulfomonilaceae, Desulfocapsaceae, and Desulfovibrionaceae (Desulfobacterota) successively established growing populations (up to 2.9% relative abundance) despite weekly periods of oxygen exposures at 133 µM (50% air saturation). Adaptation mechanisms were analyzed by genome-centric metatranscriptomics. Despite a global drop in gene expression during oxic phases, the perpetuation of gene expression for energy metabolism was observed for all SRBs. The transcriptional response pattern for oxygen resistance was differentiated across individual SRBs, indicating different adaptation strategies. Most SRB transcribed differing sets of genes for oxygen consumption, reactive oxygen species detoxification, and repair of oxidized proteins as a response to the periodical redox switch from anoxic to oxic conditions. Noteworthy, a Desulfosporosinus, a Desulfovibrionaceaea, and a Desulfocapsaceaea representative maintained high transcript levels of genes encoding oxygen defense proteins even under anoxic conditions, while representing dominant SRB populations after half a year of bioreactor operation.ConclusionsIn situ-relevant peatland SRB established large populations despite periodic one-week oxygen levels that are one order of magnitude higher than known to be tolerated by pure cultures of SRB. The observed decrease in gene expression regulation may be key to withstand periodically occurring changes in redox regimes in these otherwise strictly anaerobic microorganisms. Our study provides important insights into the stress response of SRB that drives sulfur cycling at oxic-anoxic interphases.1UtHR5dBbf2f8WaGLBYUtHVideo

A novel conceptual design for self-healing of cracked cementitious composites incorporating two bacteria-based capsules

Expanded polystyrene (EPS) is a low-density material prone to float during composite mixing and vibration. Inspired by this, a two-bacteria-capsule system was reported in this study to enhance the self-healing capacity of cracked mortar. Specifically, the BC-A capsule, containing aerobic bacteria, EPS, and superabsorbent polymer (SAP), and the BC-N capsule, containing anaerobic bacteria and SAP, are prepared through granulation using polyethylene glycol. Sulphoaluminate cement and epoxy resin are used to encapsulate the core materials. The BC-A capsules automatically float in the composite preparation process, while the BC-N capsules are distributed in the middle and bottom regions due to extrusion effect. Upon capsule rupture, the two types of bacteria are released in regions favorable for biomineralization, corresponding to the principle that oxygen concentration reduces along the crack depth. The self-healing behaviour was evaluated as well as the healing products were characterized. The results showed that the capsules cracked simultaneously with the composite and the coating effectively avoided premature release of the self-healing materials. Cementitious composites containing double capsules achieved 90 % closure of cracks with initial widths of 50–600 μm. The three-dimensional healing capacity was significantly enhanced, particularly in terms of impermeability and strength recovery ratio. The main healing products in the cracks were calcite and swollen SAP. The swollen SAP provided nucleation sites and enough water for biomineralization in the healing process.