Anaerobe最新文献

Endometriosis is a chronic, inflammatory gynecological condition characterized by the ectopic growth of endometrial-like tissue, with an unclear etiology and limited treatment efficacy. Recent studies implicate the oral and gut commensal bacterium Fusobacterium nucleatum in the pathogenesis of endometriosis, with uterine colonization reported in up to 64% of affected women. This review highlights the potential role of F. nucleatum in disease progression, particularly through its metabolic activation within the endometrial microenvironment. We explore the contribution of key bacterial metabolites (formate, lactate, and hydrogen sulfide), proteins (FadA and Fap2), and lipids (oxidized LDL, lysophosphatidylcholines, and saturated fatty acids) to inflammation, immune evasion, and epithelial-mesenchymal transition (EMT), features that overlap with tumor biology. The review also investigates the preferential triggers of F. nucleatum translocation into the endometrium. Host factors such as hypoxia, estrogen dominance, and retrograde menstruation appear to create a permissive microenvironment that potentially facilitates F. nucleatum colonization and virulence. While current therapeutic strategies largely neglect microbial involvement, emerging approaches including targeted antimicrobials, probiotics, immunomodulators, and microenvironmental modulation offer promising avenues for microbiome-informed endometriosis management. This narrative review also underscores the urgent need for longitudinal, in vivo studies to characterize the relationship between the oral, gut, and endometrial microbiomes and their impact on disease onset and progression.

Objectives: Bovine digital dermatitis (BDD) is a globally endemic, painful infectious foot disease of cattle; however, gaps in knowledge regarding treatment efficacy limit our ability to control it. Our objectives were to collect data on minimum inhibitory concentrations and minimum bactericidal concentrations (MICs and MBCs) for conventional and naturally derived therapeutic agents against specific Treponema strains important in BDD pathogenesis in the context of the need for responsible use of antimicrobials. Since antibacterial metals are widely used to control infectious lameness in ruminants, we also examine BDD treponeme susceptibility to heavy metals; and identify evidence of mechanisms for heavy metal resistance in BDD treponemes in comparison with other ruminant infectious lameness pathogens Fusobacterium necrophorum subsp. necrophorum and Dichelobacter nodosus.

Methods: We used a broth microdilution assay to collect MIC and MBC data for Treponema phagedenis (strain T320A) and Treponema pedis (strain T3552B) against the relevant antimicrobials. We used encoded protein sequences in a heavy metal resistance database (BacMet) together with comparative genomics to identify and compare metal resistance genes (MRGs) for T. phagedenis, T. pedis, F. necrophorum subsp. necrophorum and D. nodosus.

Results: BDD treponemes were susceptible to four of seven conventional antimicrobials tested: cefixime, ceftriaxone, linezolid and metronidazole. Six naturally derived therapeutic agents demonstrated intermediate susceptibility values and may be suitable as topical treatments. We identified reduced BDD treponeme susceptibility to zinc and nickel sulphate compared with copper sulphate, indicating evidence of heavy metal tolerance, and identified zinc and manganese MRGs (tro and mntA) in the treponeme genomes, with tro present across a range of treponemes but absent for F. necrophorum and D. nodosus. Comparative genomics of the tro operon highlighted further T. pedis genome features potentially related to heavy metal tolerance.

Conclusions: We have identified several novel therapeutics with in vitro efficacy against BDD associated treponemes. Moreover, differences in presence of MRGs and in vitro susceptibility across lameness associated bacteria indicate heavy metal tolerance to zinc in BDD treponemes but not in other relevant ruminant lameness associated bacteria, potentially mediated by the tro metal resistance gene. These data appear to explain differences in clinical treatment responses to zinc sulphate observed for different ruminant infectious lameness diseases depending on presence or absence of treponemes and should help inform more tailored treatment approaches in the future.

Anaerobic bacteria in the human intestinal microbiota play a pivotal role in antibiotic resistance, primarily through the production of β-lactamases. This narrative review explores the diversity of β-lactamases found in intestinal anaerobes, their functional characteristics, and clinical implications. Species of the genus Bacteroides are major producers, harboring enzymes from Ambler classes A (e.g. CepA, CfxA and CblA), B (e.g. CfiA and CcrA) and D (e.g. OXA-347), with activity ranging from cephalosporinases to carbapenemases and oxacillinases. Other gut members, including Clostridioides difficile, Fusobacterium nucleatum, and Acidaminococcus fermentans, also encode specific β-lactamases. These enzymes contribute to microbiota resilience following β-lactam exposure and can protect neighboring bacteria via extracellular degradation. This protective mechanism has inspired therapeutic applications, such as recombinant β-lactamases (ribaxamase, SYN-006) designed to preserve gut integrity during antibiotic therapy. Understanding these intrinsic resistance mechanisms is essential for optimizing antibiotic stewardship and mitigating the spread of resistance genes.

Clostridioides difficile affects humans, and several other animal species, such as horses, pigs, gerbils, guinea pigs, hamsters, and rabbits. This microorganism has also been isolated from the gastrointestinal tract of healthy individuals of a wide variety of animal species in which its association with disease is not known. Traditionally, in most domestic animal species, C. difficile-infection disease (CDI) was antibiotic-associated, although in the past few years more cases in which no antibiotic association was known have been described. In addition, no antibiotic association has been described in pigs. In most animals CDI is not age-associated, although in pigs, the disease is seen almost exclusively in neonatal animals. In horses CDI is highly prevalent, and suggested predisposing factors, in addition to antibiotic treatment and hospitalization, include co-infections with other bacteria or parasites, intestinal displacements, transportation, surgical or medical treatment and nasogastric intubation. Although in recent years a substantial amount of evidence has been provided suggesting that CDI is a zoonosis, definitive evidence in this regard is lacking.

This study evaluated the performance of antimicrobial susceptibility testing (AST) for anaerobic bacteria among 35 clinical microbiology laboratories in Germany and Austria through an interlaboratory comparison (ILC) challenge. A panel of five anaerobic bacterial strains (two Bacteroides fragilis, and one each of Phocaeicola vulgatus, Clostridium perfringens and Fusobacterium necrophorum) was tested by the participating laboratories against a panel of antibiotics (piperacillin-tazobactam, meropenem, metronidazole, clindamycin and/or benzylpenicillin) using the EUCAST disc diffusion methodology. This method was evaluated in comparison with the standard reference method, and categorical agreement with expected results was high (≥90%), with notable exceptions for piperacillin-tazobactam (88.6% and 80.0% in two of the five strains, respectively). The observed discrepancies underscore that the method requires local technical expertise in combination not only with continuous internal quality control but also with external quality assurance.

Objective: The objective of this study was to characterize the antimicrobial susceptibility of Clostridium perfringens isolates recovered from healthy broiler chicken, turkey, and layer flocks in Canada, and to assess potential associations between observed antimicrobial susceptibility test (AST) results and reported antimicrobial use (AMU).

Methods: AMU data from questionnaires, and fecal samples for AST, were collected by 17 poultry veterinarians across Canada. Data from 210 broiler chicken, 91 turkey, and 66 layer chicken flocks from 2017 to 2018 (broilers only), 2021, and 2023 were analyzed. Minimum inhibitory concentration (MIC) results were categorized as high or low based on available clinical breakpoints. Based on levels of AMU and distributions of MIC data, mixed-effect logistic regression models were built to examine the relationship between bacitracin use and high MICs in broilers and turkeys.

Results: Bacitracin was the most commonly reported antimicrobial used across all three poultry commodities studied. Significant differences in MIC distributions for bacitracin were observed among the three commodities, with broilers demonstrating the highest percentage of isolates in the upper measurable MIC range. Logistic regression analysis revealed a significant relationship (P-value ≤0.05) between bacitracin use and MIC values. Specifically, each incremental increase of 1 mg/kg in bacitracin use raised the odds of detecting a high MIC value by 4.5 % in broilers (OR = 1.045) and 9.6 % in turkeys (OR = 1.096).

Conclusions: These findings suggest that elevated AMU, particularly bacitracin, is associated with reduced susceptibility (higher MICs) in C. perfringens isolates from poultry, highlighting that prudent use of antimicrobials is needed to preserve antimicrobial efficacy.

Objective: The genus Thermoanaerobacter is comprised of strictly anaerobic, thermophilic, rod-shaped bacteria predominantly isolated from geothermal environments. Due to phylogenetic and taxonomic overlaps among certain species, this study aims to clarify the taxonomic status of key Thermoanaerobacter members through genome-based analyses.

Methods: We conducted a comprehensive taxonomic re-evaluation using multiple genomic metrics, including digital DNA-DNA hybridization (dDDH), average nucleotide identity (ANI via FastANI), average amino acid identity (AAI), and percentage of conserved proteins (POCP). These analyses were supported by 16S rRNA gene sequencing and genome-based phylogenomic reconstruction.

Results: Genome-based metrics and phylogenomic analyses revealed several taxonomic inconsistencies within the genus. As a result, Thermoanaerobacter thermohydrosulfuricus is redefined to include Thermoanaerobacter ethanolicus subsp. thermohydrosulfuricus, Thermoanaerobacter ethanolicus subsp. siderophilus, Thermoanaerobacter ethanolicus subsp. ethanolicus and Thermoanaerobacter ethanolicus subsp. indiensis under Thermoanaerobacter thermohydrosulfuricus subsp. thermohydrosulfuricus subsp. nov., while Thermoanaerobacter wiegelii is assigned to Thermoanaerobacter thermohydrosulfuricus subsp. wiegelii subsp. nov., comb. nov. Thermoanaerobacter pseudethanolicus, Thermoanaerobacter brockii subsp. finnii, and Thermoanaerobacter brockii subsp. lactiethylicus DSM 9801^T were reclassified as Thermoanaerobacter brockii. Additionally, Thermoanaerobacter mathranii, Thermoanaerobacter italicus, and Thermoanaerobacter pentosaceus are reclassified as Thermoanaerobacter thermocopriae.

Conclusions: This study supports a taxonomic rearrangement within Thermoanaerobacter, refining species boundaries based on robust genomic evidence. The proposed changes enhance the taxonomic resolution and phylogenetic consistency of thermophilic anaerobic bacteria within this genus.

UDCA exhibits limited direct bacteriostatic activity against Clostridioides difficile with a high MIC₉₀ of >128 μg/mL against 121 clinical strains. However, compared with vancomycin, UDCA significantly impedes biofilm formation and bacterial adherence at subinhibitory concentrations, which may be the therapeutic advantages of UDCA and support this old drug to be further developed for CDI prevention.