Peptostreptococcus anaerobius: Pathogenicity, identification, and antimicrobial susceptibility. Review of monobacterial infections and addition of a case of urinary tract infection directly identified from a urine sample by MALDI-TOF MS

Dynamic changes and metabolic function of intestinal flora in patients with postoperative pneumonia after lung cancer surgery

BACKGROUND

Postoperative pneumonia (POP) is the most prevalent postoperative complication following lung cancer surgery. It is a crucial factor that influences surgical success and the rapid recovery of patients. Studies on the gut-lung axis have suggested that changes in the structural and functional aspects of intestinal flora are implicated in the incidents and development of pulmonary infection. This study aims to reveal the dynamic changes and metabolic function of intestinal flora in lung cancer patients with POP, with the ultimate goal of providing novel insights and targets for the prevention and treatment of POP.

METHODS

This study includes three groups: healthy control group, lung cancer with POP group, and lung cancer without POP group. We collected stool samples from healthy individuals, preoperative and first post-infection stool samples from the POP group, and preoperative and first postoperative stool samples from the non-POP group. The hypervariable V3-V4 regions of 16S rRNA gene were sequenced using Illumina MiSeq high-throughput sequencing technology.

RESULTS

The alpha diversity index was lower in the POP group than in the healthy group, the beta diversity index was also different between the two groups (P <  0.05). Eggerthella, Coprobacillus, and Peptostreptococcus were abundant in the intestinal tracts of the POP group in preoperative and postoperative infections. There was a decrease in the abundance of beneficial genera such as Blautia and an increase in the abundance of pathogenic or opportunistic pathogens such as Bacteroides. The phosphatidylinositol signaling system abundance increased, whereas the abundance of phenazine, phenylalanine, tyrosine, and tryptophan biosyntheses was reduced in the POP group during postoperative infection.

CONCLUSION

Patients with POP after lung cancer surgery have a distinct spectrum of intestinal flora. The intestinal flora displays a reduction in diversity and an increase in the presence of potential pathogenic bacteria, which impact metabolic functions.

Microbiological and toxicity analyses of the synthetic polymer polyhexamethylene guanidine hydrochloride against endodontic microorganisms

Failures in endodontic treatments are common due to microbial resistance in the pulp canal. The study evaluated the in vitro activity of polyhexamethylene guanidine hydrochloride (PHMGH) against endodontic strains, as well as in vivo toxicity. Using minimum inhibitory concentration and minimum bactericidal concentration techniques, PHMGH was effective against all microorganisms, even at low concentrations. At 50.0 µg/mL, it inhibited Enterococcus faecalis; furthermore, when compared to chlorhexidine (CLX), it demonstrated values 19 times lower against Candida albicans. The polymer's activity was also determined by agar diffusion, evaluating products A (calcium hydroxide - Ca(OH)2, as a reference), B (Ca(OH)2 combined with physiological solution, reference with a vehicle), C (PHMGH 6.25%), D (PHMGH 3.125%), E (PHMGH 1.5625%), F (PHMGH 0.78125%), G (PHMGH 6.25% and Ca(OH)2), H (PHMGH 3.125% and Ca(OH)2), I (PHMGH 1.5625% and Ca(OH)2), J (PHMGH 0.78125% and Ca(OH)2), and K (positive control, CLX 0.12%). Products containing PHMGH were more effective than the references against all strains, and C, D, and G were more effective than CLX against Peptostreptococcus anaerobius, Actinomyces naeslundii, and Actinomyces viscosus. According to the fractional inhibitory concentration index, the combination of PHMGH and CLX showed indifference for Peptostreptococcus anaerobius, Actinomyces naeslundii, Actinomyces viscosus and Escherichia coli, antagonism for Candida albicans, and synergy for Enterococcus faecalis. The toxicity of PHMGH at different concentrations was tested in Caenorhabditis elegans and did not show lethality in nematodes, with the LC50 observed only at the highest concentration (100 µg/mL) after two days of exposure. It is suggested that PHMGH exhibited antimicrobial activity against endodontic strains and low toxicity, raising expectations for new preventive and therapeutic products in endodontics.

Remodelling of the healthy foal's conjunctival microbiome in the first two months of life

Introduction

The aim of the study was to explore and characterise healthy foals' eye microbiomes in the first two months of life.

Material and Methods

Conjunctival swabs were collected three times, not later than 12 h after delivery and again at the end of the first and the second months of life from six clinically healthy foals of the Polish Konik breed. The average interval between the first and second samplings was 33.3 days and between the second and third was 35.6 days. Next-generation sequencing performed on a MiSeq sequencer in paired-end technology was used to analyse the composition of the conjunctival microbiota.

Results

Paired one-sided t-tests revealed that conjunctival microbiota diversity was the lowest in the first 24 h of life and significantly increased between birth and the first month. The most prevalent family throughout the study was Micrococcaceae and the most prevalent genus was Corynebacterium. Sequences of potentially pathogenic bacteria such as Pseudomonas, Acinetobacter and Streptococcus spp. that may be involved in inflammatory processes were identified. Ocular commensals such as Corynebacterium and Lactobacillaceae that were found in the ocular surface microbiome of the foals are believed to be capable of restoring the ocular microbiome and maintaining balance.

Conclusion

A healthy ocular surface microbiota in the early period of a foal's life develops dynamically and changes its composition.

Structure-Based Modeling of the Gut Bacteria-Host Interactome Through Statistical Analysis of Domain-Domain Associations Using Machine Learning

The gut microbiome, a complex ecosystem of microorganisms, plays a pivotal role in human health and disease. The gut microbiome's influence extends beyond the digestive system to various organs, and its imbalance is linked to a wide range of diseases, including cancer and neurodevelopmental, inflammatory, metabolic, cardiovascular, autoimmune, and psychiatric diseases. Despite its significance, the interactions between gut bacteria and human proteins remain understudied, with less than 20,000 experimentally validated protein interactions between the host and any bacteria species. This study addresses this knowledge gap by predicting a protein-protein interaction network between gut bacterial and human proteins. Using statistical associations between Pfam domains, a comprehensive dataset of over one million experimentally validated pan-bacterial-human protein interactions, as well as inter- and intra-species protein interactions from various organisms, were used for the development of a machine learning-based prediction method to uncover key regulatory molecules in this dynamic system. This study's findings contribute to the understanding of the intricate gut microbiome-host relationship and pave the way for future experimental validation and therapeutic strategies targeting the gut microbiome interplay.

Helicobacter pylori Inhibition, Gastritis Attenuation, and Gut Microbiota Protection in C57BL/6 Mice by Ligilactobacillus salivarius NCUH062003

Helicobacter pylori (H. pylori), one of the most prevalent pathogenic bacteria worldwide, is the leading cause of gastritis, gastric intestinal metaplasia, and gastric cancer. Antibiotics, the conventional treatment for eliminating H. pylori, often lead to severe bacterial resistance, gut dysbiosis, and hepatic insufficiency and fail to address the inflammatory response or gastric mucosal damage caused by H. pylori infection. In this study, based on 10-week animal experiments, two models of L. salivarius NCUH062003 for the prophylaxis and therapy of H. pylori infection in C57BL/6 mice were established; a comprehensive comparative analysis was performed to investigate the anti-H. pylori effect of probiotics, the reduction in inflammation, and repair of gastric mucosal damage. ELISA, immunohistochemistry, and pathology analyses showed that NCUH062003 decreased the expression of pro-inflammatory cytokine interleukins (IL-1β, IL-6) and myeloperoxidase (MPO) and reduced neutrophil infiltration in the gastric mucosa lamina propria. Immunofluorescence and biochemical analysis showed that NCUH062003 resisted gastric epithelial cell apoptosis, increased the level of superoxide dismutase (SOD) in gastric mucosa, and promoted the expression of tight junction protein ZO1 and Occludin. In addition, through high-throughput sequencing, in the probiotic therapy and prophylactic mode, the diversity and composition of the gut microbiota of HP-infected mice were clarified, the potential functions of the gut microbiota were analyzed, the levels of short-chain fatty acids (SCFAs) were measured, and the effects of L. salivarius NCUH062003 on the gut microbiota and its metabolites in HP-infected mice treated with amoxicillin/metronidazole were revealed. This study provides functional strain resources for the development and application of microbial agents seeking to antagonize H. pylori beyond antibiotics.

Peptostreptococcus Anaerobius enhances dextran sulfate sodium-induced colitis by promoting nf-κB-NLRP3-Dependent macrophage pyroptosis

Evidence indicates that gut microbiota is crucial in ulcerative colitis (UC) development. Increased Peptostreptococcus species abundance is linked to UC, but its role and mechanisms in intestinal inflammation are not well understood. This study used a dextran sulfate sodium (DSS)-induced colitis model in mice, and different bacterial strains were administered via gavage. We assessed clinical manifestations, colonic barrier function, gut microbiota composition, and levels of inflammatory cytokines, NOD-like receptor family pyrin domain-containing 3 (NLRP3) signaling molecules, and pyroptosis-related proteins. Mouse bone marrow-derived macrophages (BMDMs) were infected with Peptostreptococcus anaerobius at different time points and multiplicities of infection (MOI). Cell viability and the expression of NLRP3 signaling molecules and pyroptosis-associated proteins were assessed. The inhibitors C29, TAK-242, and MCC950 were employed for Toll-like receptor (TLR) and NLRP3 signaling pathways. It was observed that P. anaerobius exacerbated intestinal inflammation and barrier injury in DSS-induced colitis in mice. Additionally, P. anaerobius contributed to gut microbiota dysbiosis during colitis progression. P. anaerobius induced the expression of NLRP3 signaling molecules and pyroptosis-associated proteins in mouse colitis tissues. In vitro assays demonstrated that P. anaerobius activated NLRP3 inflammasome and evoked gasdermin D-mediated pyroptosis and interleukin (IL)-1β secretion in macrophages. Furthermore, TLR2 and TLR4 were identified as key mediators of P. anaerobius-induced macrophage pyroptosis via activation of the Nuclear Factor-kappa B (NF-κB)-NLRP3 pathway. In conclusion, P. anaerobius promotes macrophage pyroptosis and IL-1β secretion through the TLR2/4-NF-κB-NLRP3 signaling axis, thereby aggravating colitis. P. anaerobius may represent a potential risk factor for UC development.

Microbiome and Abdominopelvic Radiotherapy Related Chronic Enteritis: A Microbiome-based Mechanistic Role of Probiotics and Antibiotics

Chronic diarrhea and abdominal pain after radiotherapy continue to be a problem in cancer survivors. Gut microbiomes are essential for preventing intestinal inflammation, maintaining intestinal integrity, maintaining enterohepatic circulation, regulating bile acid metabolism, and absorption of nutrients, including fat-soluble vitamins. Gut microbiome dysbiosis is expected to cause inflammation, bile acid malabsorption, malnutrition, and associated symptoms. Postradiotherapy, Firmicutes and Bacteroidetes phylum are significantly decreased while Fusobacteria and other unclassified bacteria are increased. Available evidence suggests harmful bacteria Veillonella, Erysipelotrichaceae, and Ruminococcus are sensitive to Metronidazole or Ciprofloxacin. Beneficial bacteria lactobacillus and Bifidobacterium are relatively resistant to metronidazole. We hypothesize and provide an evidence-based review that short-course targeted antibiotics followed by specific probiotics may lead to alleviation of radiation enteritis.

Therapeutic effects of coptisine derivative EHLJ7 on colorectal cancer by inhibiting PI3K/AKT pathway

Colorectal cancer (CRC) is the third most common cancer in the world with high mortality rate. EHLJ7 is a quaternary coptisine derivative synthesized by our institute. In this study, the role and mechanism of EHLJ7 on CRC are further elucidated. Using target fishing, colon cancer-associated target screening and molecular docking analysis, PI3K/AKT pathway was selected for the target of EHLJ7 at CRC. Results of Flow cytometry, wound healing assay and transwell migration assay confirmed that EHLJ7 could inhibit migration and apoptosis of colon cancer cells by specifically inhibiting PI3K/AKT pathway in vitro. Xenograft tumor models and a newly established azoxymethane (AOM)/dextran sulfate sodium (DSS)/Peptostreptococcus anaerobiu (P.anaerobius)-induced CRC mouse model are applied to access the anti-cancer action and mechanism of EHLJ7 using western-blot, immunohistochemistry and analysis of exosomes. The key findings in this study are listed as follows: (1) EHLJ7 exerts superior anti-tumor effect with good safety on Xenograft tumor model and CRC model; (2) EHLJ7 exerted its anti-CRC effect by specifically inhibiting PI3K/AKT pathway and apoptosis in vivo and in vitro. In summary, we demonstrated that EHLJ7 exerts therapeutic effect against CRC by PI3K/AKT pathway, which made it possible as a potentially effective compound for the treatment of CRC.

A pattern of microbiological colonization of orthodontic miniscrew implants

INTRODUCTION

Current orthodontic literature reveals a lack of studies on bacterial colonization of orthodontic miniscrew implants (MSI) and their role in the stability of MSI. This study aimed to determine the pattern of microbiological colonization of miniscrew implants in 2 major age groups, to compare it with the microbial flora of gingival sulci in the same group of patients and to compare microbial flora in successful and failed miniscrews.

METHODS

The study involved 102 MSI placed in 32 orthodontic subjects in 2 age groups: (1) aged ≤14 years and (2) aged >14 years. Gingival and peri-mini implant crevicular fluid samples were collected using sterile paper points (International Organization for Standardization no. 35) >3 months and processed by conventional microbiologic culture and biochemical techniques. A microbiologist characterized and identified the bacteria, and the results were subjected to statistical analysis.

RESULTS

Initial colonization was reported within 24 hours, with Streptococci being the dominant colonizer. The relative proportion of anaerobic bacteria over aerobic bacteria increased over time in peri-mini implant crevicular fluid. Group 1 had greater Citrobacter (P = 0.036) and Parvimonas micra (P = 0.016) colonizing MSI than group 2. Failed MSI showed a significantly higher presence of Parvimonas micra (P = 0.008) in group 1 and Staphylococci (P = 0.008), Enterococci (P = 0.011), and Parvimonas micra (P <0.001) in group 2.

CONCLUSIONS

Microbial colonization around MSI is established within 24 hours. Compared to gingival crevicular fluid, peri-mini implant crevicular fluid is colonized by a higher proportion of Staphylococci, facultative enteric commensals and anaerobic cocci. The failed miniscrews showed a higher proportion of Staphylococci, Enterobacter, and Parvimonas micra, suggesting their possible role in the stability of MSI. The bacterial profile of MSI varies with age.

Rumen microbiota responses to the enzymatic hydrolyzed cottonseed peptide supplement under high-concentrate diet feeding process

In current dairy production, dietary energy is always excessively provided with a high-concentrate diet feeding to improve milk production. However, this feeding practice disturbed the rumen microbial ecosystem and the balance between ruminal energy and nitrogen, resulting in decreased nutrient fermentability, which in turn declined the milk yield of dairy cows. Therefore, supplementation of dietary degradable nitrogen may be helpful for high dairy production. In this study, we evaluated the regulatory effects of easily utilized enzymatic hydrolyzed cottonseed peptide (EHP) supplements on rumen microbiota communities and rumen nutrient fermentability under high-concentrate feeding. For this purpose, a gradient concentrate of EHP (from 0.2 to 1.0%) was added to the high-concentrate basal substrates for an in vitro experiment. Each treatment contained three replicates, with three bottles in each replicate. Rumen fermentable parameters included microbial protein content, volatile fatty acids, and ammonia-N; the rumen nutrient degradability of dry matter, crude protein, neutral detergent fiber, acid detergent fiber, ether extracts, calcium, and phosphorus were further investigated after in vitro fermentation for 72 h. Then, rumen microbiota communities and their correlation with ruminal fermentation parameters and rumen nutritional degradability were analyzed to understand the regulatory mechanism of the EHP supplements on rumen fermentability. Results indicate that treatment with 0.6% of EHP supplements had the highest content of acetate, butyrate, and neutral detergent fiber degradability among all treatments. Furthermore, EHP supplements significantly increased the relative abundance of rumen cellulose and starch-degrading bacteria such as Ruminococcus, Bifidobacterium, and Acetitomaculum, and the high nitrogen utilizing bacteria Butyrivibrio and Pseudobutyrivibrio, which may further promote the rumen carbohydrate and nitrogen metabolism. In summary, supplementation of easily degraded small peptides helps reestablish rumen energy and nitrogen balance to promote the rumen fermentable functions and nutritional degradability under high-concentrate diet feeding circumstances. These findings may further promote dairy production.

“Omic” Approaches to Bacteria and Antibiotic Resistance Identification

The quick and accurate identification of microorganisms and the study of resistance to antibiotics is crucial in the economic and industrial fields along with medicine. One of the fastest-growing identification methods is the spectrometric approach consisting in the matrix-assisted laser ionization/desorption using a time-of-flight analyzer (MALDI-TOF MS), which has many advantages over conventional methods for the determination of microorganisms presented. Thanks to the use of a multiomic approach in the MALDI-TOF MS analysis, it is possible to obtain a broad spectrum of data allowing the identification of microorganisms, understanding their interactions and the analysis of antibiotic resistance mechanisms. In addition, the literature data indicate the possibility of a significant reduction in the time of the sample preparation and analysis time, which will enable a faster initiation of the treatment of patients. However, it is still necessary to improve the process of identifying and supplementing the existing databases along with creating new ones. This review summarizes the use of “-omics” approaches in the MALDI TOF MS analysis, including in bacterial identification and antibiotic resistance mechanisms analysis.

Chalcones with potential antibacterial and antibiofilm activities against periodontopathogenic bacteria

OBJECTIVES

Periodontitis is a pathology resulting from complex interaction of microorganisms in the dental biofilm with the host's immune system. Increased use of antibiotics associated with their inappropriate use has increased resistance levels in anaerobic bacteria. Therefore, identifying new antimicrobial compounds, such as chalcones, is urgent. This study evaluates the antibacterial activity and the antibiofilm activity of 15 chalcones against the periodontopathogenic bacteria Prevotella nigrescens (ATCC 33563), P. oralis (ATCC 33269), Peptostreptococcus anaerobius (ATCC 27337), Actinomyces viscosus (ATCC 43146), Porphyromonas asaccharolytica (ATCC 25260), and Fusobacterium nucleatum (ATCC 25586).

METHODS

The compounds were evaluated by minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) tests.

RESULTS

Compounds 1-6 showed good antibacterial and antibiofilm activities against most of the evaluated bacteria: MIC was lower than or equal to 6.25 μg/mL, biofilm biomass was reduced by 95%, and the compounds at concentrations between 0.78 and 100 μg/mL totally inhibited cell viability. Among the tested chalcones, 3 stood out: it was effective against all the bacteria, as revealed by the MIC and MBIC results.

CONCLUSIONS

Our results have consolidated a base for the development of new studies on the effects of the tested chalcones as agents to combat and to prevent periodontitis.