Anaerobe最新文献

Infections from anaerobic microorganisms result from breached mucosal barriers, posing a significant mortality risk. A retrospective study at Hospital Universitario La Paz (Madrid) from 2010 to 2022 analyzed 491 (6.17 %) anaerobic bacteremia cases out of 7956 significant bacteremia cases among 171,833 blood culture requests. Bacteroides fragilis was the most frequently isolated species (28.3 %), followed by Clostridium perfringens (13.6 %). B. fragilis showed good susceptibility to amoxicillin/ clavulanic acid (86 %), piperacillin/tazobactam (86 %), and metronidazole (87.7 %). In general, non-fragilis Bacteroides species showed low susceptibility to penicillin (7 %), amoxicillin (17.5 %), and clindamycin (64.9 %). Of our 13 non-perfringens Clostridium isolates, four exhibited resistance to penicillin and four showed resistance to clindamycin. Lactobacillus species were highly susceptible to antibiotics tested. Prevotella spp. showed low susceptibility to penicillin (20 %), amoxicillin (20 %), and clindamycin (40 %). The study contributes valuable data for monitoring and improving anaerobic bacteremia treatment.

Among 23 patients with multiply recurrent Clostridiodies difficile infection (mrCDI) who received bezlotoxumab at the end of antibiotic treatment a sustained clinical response of 91 % at 30 days and 78 % at 90 days was achieved. Bezlotoxumab administered at the end of antibiotic treatment was effective in patients with mrCDI.

Objectives

The purpose of this study was to identify microorganisms isolated from various periapical tissue diseases using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) and classify them via an unsupervised machine learning approach.

Methods

A total of 150 patients with various apical conditions and teeth in need of endodontic retreatment were divided into five groups, including Retreatment, Acute Apical Abscess, Chronic Apical Abscess, Acute Apical Periodontitis, and Chronic Apical Periodontitis. Samples were collected from root canals using paper points after agitating with a #10 K file then microorganisms were identified using MALDI-TOF-MS. Data were analyzed using a hierarchical clustering method. Quadruple clusters and dendrograms were formed according to similarities and dissimilarities.

Results

A total of 80 species were identified under six different phyla. The most similar microorganism species were identified ''Enterococcus faecalis'' between 21 and 23-year-old female cases in Retreatment group; ''Lactobacillus rhamnosus'' between 20 and 18-year-old male cases in Symptomatic Apical Abscess cases; ''Lactobacillus paracasei'' between 26 and 40-year-old male cases in Asymptomatic Apical Abscess cases; ''Enterococcus faecalis'' between 48 and 50-year-old female cases in Symptomatic Apical Periodontitis cases; ''Lactobacillus rhamnosus'' between 48 and 60-year-old male cases in Asymptomatic Apical Periodontitis cases.

Conclusions

MALDI-TOF MS can be considered a fast and high-throughput screening technique for microbial species identification in endodontics. Thus, it will provide valuable data for future research designs regarding periapical tissue diseases. As the MALDI-TOF MS database expands and comprehensive data becomes available, the relationship between microbial profiles and disease progression will become increasingly apparent.

Objective

The family Lachnospiraceae is affiliated with the order Clostridiales and was originally contained within Clostridial cluster XIVa. The members of Lachnospiraceae inhabiting the gut comprise the chemoorganotrophic genera, generating sundry short-chain fatty acids to supply energy to the host, and are considered to be related to obesity and gut health.

Methods

The polyphasic taxonomic approach was used to characterize the isolate YH-rum2234^T. A detailed metabolic analysis was conducted to compare the novel isolate with related strains within the family Lachnospiraceae.

Results

A fusiform, obligately anaerobic, Gram-stain-negative bacterium, YH-rum2234^T, was isolated from pig feces. Analysis of the 16 S rRNA gene sequence revealed that the similarities between the isolate and the familiarly interrelated strain Lientehia hominis KCTC 25345^T was 94.3 %. The average nucleotide identities and genome-to-genome distances of YH-rum2234^T and its closely related strains were below 85.5 % and 32.5 %, respectively. The G + C content of the genomic DNA was 49.2 mol%. The main fatty acids were C_16:0, C_14:0, and C_14:0 DMA. The major polar lipids were aminophospholipids. The cell wall did not contain the peptidoglycan meso-diaminopimelic acid.

Conclusion

Given the chemotaxonomic, phenotypic, and phylogenetic properties, YH-rum2234^T (=KCTC 25710^T = DSMZ 116041^T) represents a new genus and species in the family Lachnospiraceae. Fusibacillus kribbianus gen. nov., sp. nov. is the proposed name.

Objectives

In this work, an isothermal microcalorimeter was applied to investigate the antipathogenic activity of three probiotics (Lactobacillus acidophilus, Bifidobacterium lactis and Bifidobacterium bifidum) against Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli using the probiotics in mixed culture with the pathogenic microorganisms.

Methods

A microcalorimeter was used to monitor the growth of the microorganisms as pure cultures and as co-cultures at 37 °C. Relative growths of the probiotics and pathogenic species were determined after microcalorimetric measurements by serial dilution and plate incubation. Relative growth of mixed cultures of E. coli with L. acidophilus or B. lactis was also determined by traditional plate growth assay for 5.5 h.

Results

The results showed growth profiles of the microorganisms that were characteristic and showed different lag and peak times for the species. The pathogenic species grew faster than the probiotic species. In the co-cultures, the growth profile of both pathogenic species and probiotics could be identified with the microcalorimeter. Although the pathogenic species grew faster, at the end of the assay, the results showed that the pathogenic species were inhibited in growth by the probiotics as no viable growth of the pathogenic species was detected whereas 10⁷–10⁸ CFU/mL of the probiotics were enumerated after the microcalorimetric assay. Using the traditional plate assay, the data confirmed co-growth of the probiotics and E. coli although cell numbers of E. coli were higher than the probiotics during 5.5 h of co-culture incubation when both were inoculated at 10⁶ CFU/mL.

Conclusion

The results demonstrate the antipathogenic effects of probiotics and highlights the potential of microcalorimetry in live mixed culture assays and its limitation.

Objectives

Teicoplanin is a potential antimicrobial candidate for Clostridioides difficile infection (CDI) treatment. However, the therapeutic potential of teicoplanin against severe CDI has not been clinically proven. In the present study, we investigated the efficacy of oral teicoplanin administration against severe CDI and the recurrence of severe CDI after teicoplanin treatment in a mouse model.

Methods

A lethal CDI mouse model was established by colonizing the mice with C. difficile ATCC® 43255; they were orally administered teicoplanin (128 mg/kg/d) or vancomycin (160 mg/kg/d) for 10 d, 24 h after C. difficile spore challenge, and physiological and biological responses were monitored for 20 d after the initial antibiotic treatment. We also performed the in vitro time-kill assay and determined minimum inhibitory concentration (MIC), post-antibiotic effect, and toxin production with antibiotic exposure.

Results

The therapeutic response (survival rates, body weight change, clinical sickness score grading, C. difficile load, and toxin titer in feces) of oral teicoplanin administration was comparable to that of oral vancomycin administration in the lethal CDI mouse model. Moreover, teicoplanin treatment suppressed the re-onset of diarrhea and re-increase in toxin titer 10 d after treatment compared with that by vancomycin treatment. In in vitro experiments, teicoplanin exhibited time-dependent antibacterial activity and possessed lower MIC and longer post-antibiotic effect than vancomycin against C. difficile. C. difficile toxin production was numerically lower with teicoplanin exposure than with vancomycin exposure.

Conclusions

The results obtained from the present basic experiments could suggest that teicoplanin is a potential antibiotic for the treatment of severe CDI with recurrence-prevention activity.

Introduction

Bacteroides fragilis (B. fragilis) is considered to act in an anti-inflammatory manner on the intestinal tract. On the contrary, enterotoxigenic B. fragilis (ETBF), a subtype of B. fragilis, produces an enterotoxin (BFT; B. fragilis toxin), leading to asymptomatic chronic infections and colonic tumor formation. However, the impact of B. fragilis and ETBF on the clinical outcome of colorectal cancer (CRC) remains unclear. We aim to assess whether their presence affects the outcome in patients with CRC after curative resection.

Methods

We obtained 197 pairs of matched formalin-fixed paraffin-embedded samples from cancerous and adjacent non-cancerous tissues of patients with pathological stage (pstage) II and III CRC after curative resection. The presence of B. fragilis and ETBF were estimated using real-time polymerase chain reaction, and recurrence-free survival (RFS) and overall survival (OS) of the patients were analyzed.

Results

16 S rRNA for B. fragilis and bft DNA were detected in 120 (60.9%) and 12 (6.1%) of the 197 patients, respectively. B. fragilis-positive patients had better RFS than B. fragilis-negative patients, although that was not statistically significant. In subgroup analysis, better outcomes on RFS were observed in the presence of B. fragilis in pstage II and left-sided CRC. The association of B. fragilis positivity on OS was accentuated in the depth of T4 subgroup. No significant differences were observed in RFS and OS between ETBF and non-toxigenic B. fragilis.

Conclusions

Our findings suggest that the presence of B. fragilis is associated with better outcomes in patients with pstage II and III CRC after curative resection.

Objectives

This study evaluated the effect of particle size and dosage of granular activated carbon (GAC) on methane production from the anaerobic digestion of raw effluent (RE) of swine wastewater, and the solid (SF) and liquid (LF) fractions. The effect of temperature using the selected size and dosage of GAC was also evaluated.

Methods

60 mL of swine wastewater were inoculated with anaerobic granular sludge and GAC at different dosages and particle size. The cultures were incubated at different temperatures at 130 rpm. The kinetic parameters from experimental data were obtained using the Gompertz model.

Results

The cultures with the LF and GAC (75–150 μm, 15 g/L) increased 1.87-fold the methane production compared to the control without GAC. The GAC at 75–150 μm showed lower lag phases and higher R_max than the cultures with GAC at 590–600 μm. The cumulative methane production at 45 °C with the RE + GAC was 7.4-fold higher than the control. Moreover, methane production at 45 °C significantly increased with the cultures LF + GAC (6.0-fold) and SF + GAC (2.0-fold). The highest production of volatile fatty acids and ammonium was obtained at 45 °C regardless of the substrate and the addition of GAC contributed to a higher extent than the cultures lacking GAC. In most cases, the kinetic parameters at 30 °C and 37 °C were also higher with GAC.

Conclusions

GAC contributed to improving the fermentative and methanogenesis stages during the anaerobic digestion of fractions, evidenced by an improvement in the kinetic parameters.

Objective

Clostridium perfringens causes food poisoning and gas gangrene, a serious wound-associated infection. C. perfringens cells adhere to collagen via fibronectin (Fn). We thought that C. perfringens cells have some kind of Fn receptor. We investigated whether the peptidoglycan hydrolase of C. perfringens, i.e., autolysin (Acp), is implicated in Fn binding to C. perfringens cells.

Methods

This study used recombinant Acp fragments, human Fn and knockout mutants (C. perfringens 13 acp::erm and HN13 ΔfbpC ΔfbpD). Ligand blotting, Western blotting analysis, and complementation tests were performed. The Fn-binding activity of each mutant was evaluated by ELISA.

Results

From an Fn-binding assay using recombinant Acp fragments, Fn was found to bind to the catalytic domain of Acp. In mutant cells lacking Acp, Fn binding was significantly decreased, but was restored by the complementation of the acp gene. There are three known kinds of Fn-binding proteins in C. perfringens: FbpC, FbpD, and glyceraldehyde-3-phosphate dehydrogenase. We found no difference in Fn-binding activity between the mutant cells lacking both FbpC and FbpD (SAK3 cells) and the wild-type cells, indicating that these Fn-binding proteins are not involved in Fn binding to C. perfringens cells.

Conclusions

We found that the Acp is an Fn-binding protein that acts as an Fn receptor on the surface of C. perfringens cells.

The gut is host to a diverse array of microbiota that constitute a complex ecological system crucial to human physiology. Disruptors to the normal host microbiota, such as antimicrobials, can cause a loss of species diversity in the gut, reducing its ability to resist colonization by invading pathogens and potentially leading to colonization with antimicrobial resistant organisms (AROs). ARO negatively impact gut health by disrupting the usual heterogeneity of gut microbiota and have the potential to cause systemic disease. In recent years, fecal microbiota transplantation (FMT) has been increasingly explored in the management of specific disease states such as Clostridioides difficile infection (CDI). Promising data from management of CDI has led to considerable interest in understanding the role of therapeutics to restore the gut microbiota to a healthy state. This review aims to discuss key studies that highlight the current landscape, and explore existing clinical evidence, for the use of FMT and microbiome-based therapeutics in combating intestinal colonization with ARO. We also explore potential future directions of such therapeutics and discuss unaddressed needs in this field that merit further investigation.