ABSTRACT
Oxygen tolerance of anaerobes is a virulence factor, but can also be a beneficial property. Many species have evolved to tolerate or take advantage of the presence of low, especially nanaerobic (≤0.14%) oxygen concentrations. Oxygen tolerance is genus-, species- and strain-dependent according to their protective mechanisms. It was better expressed in some pathogenic species such as Bacteroides fragilis, Clostridioides difficile, and Clostridium perfringens, as well as in Akkermansia muciniphila than in other potential probiotics such as Alistipes, Blautia and Roseburia spp. Different degrees of oxygen sensitivity were found between the strains of Anaerostipes, Faecalibacterium, and Bifidobacterium spp. Importantly, clostridial spores and anaerobes in biofilms are protected from oxidation. Rubrerythrins and flavodiiron proteins and two regulators (sigma factor B and PerR) contribute to C. difficile protection from reactive oxygen species (ROS). The frequent pathogen, B. fragilis, has numerous protective factors such as enzymes (catalase, superoxide dismutase, alkyl hydroperoxidase, thioredoxin peroxidase, and aerobic-type NrdAB ribonucleotide reductase), and nanaerobic respiration. Seven proteins confer strain-specific oxygen adaptation of Faecalibacterium prausnitzii. Oxygen tolerance protects anaerobes from ROS, shields their DNA and modulates gene expression. Furthermore, oxygen can induce mutations leading to antibiotic resistance as shown in Prevotella melaninogenica. Some Faecalibacterium, Anaerostipes, Bifidobacterium, and Akkermansia strains from the intestinal microbiota exhibiting oxygen tolerance may become next-generation probiotic candidates. Further studies are needed to reveal oxygen effects on more anaerobic species and strains, and the influence of oxygen on antibiotic resistance. More studies on oxygen-tolerant probiotic strains can be useful to optimize biotechnological methods.
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Polycyclic polyprenylated acylphloroglucinols (PPAPs) comprise a large group of compounds of mostly plant origin. The best-known compound is hyperforin from St. John's wort with its antidepressant, antitumor and antimicrobial properties. The chemical synthesis of PPAP variants allows the generation of compounds with improved activity and compatibility. Here, we studied the antimicrobial activity of two synthetic PPAP-derivatives, the water-insoluble PPAP23 and the water-soluble sodium salt PPAP53. In vitro, both compounds exhibited good activity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium. Both compounds had no adverse effects on Galleria mellonella wax moth larvae. However, they were unable to protect the larvae from infection with S. aureus because components of the larval coelom neutralized the antimicrobial activity; a similar effect was also seen with serum albumin. In silico docking studies with PPAP53 revealed that it binds to the F1 pocket of human serum albumin with a binding energy of -7.5 kcal/mol. In an infection model of septic arthritis, PPAP23 decreased the formation of abscesses and S. aureus load in kidneys; in a mouse skin abscess model, topical treatment with PPAP53 reduced S. aureus counts. Both PPAPs were active against anaerobic Gram-positive gut bacteria such as neurotransmitter-producing Clostridium, Enterococcus or Ruminococcus species. Based on these results, we foresee possible applications in the decolonization of pathogens.
Subject(s)
Ketones , Methicillin-Resistant Staphylococcus aureus , Spiro Compounds , Animals , Humans , Mice , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Enterococcus faecium/drug effects , Ketones/chemistry , Ketones/pharmacology , Larva/drug effects , Methicillin-Resistant Staphylococcus aureus/drug effects , Microbial Sensitivity Tests , Molecular Docking Simulation , Moths/drug effects , Spiro Compounds/chemistry , Spiro Compounds/pharmacology , Staphylococcal Infections/drug therapyABSTRACT
The bacterial light-dependent energy metabolism can be divided into two types: oxygenic and anoxygenic photosynthesis. Bacterial oxygenic photosynthesis is similar to plants and is characteristic for cyanobacteria. Bacterial anoxygenic photosynthesis is performed by anoxygenic phototrophs, especially green sulfur bacteria (GSB; family Chlorobiaceae) and purple sulfur bacteria (PSB; family Chromatiaceae). In anoxygenic photosynthesis, hydrogen sulfide (H2S) is used as the main electron donor, which differs from plants or cyanobacteria where water is the main source of electrons. This review mainly focuses on the microbiology of GSB, which may be found in water or soil ecosystems where H2S is abundant. GSB oxidize H2S to elemental sulfur. GSB possess special structures-chlorosomes-wherein photosynthetic pigments are located. Chlorosomes are vesicles that are surrounded by a lipid monolayer that serve as light-collecting antennas. The carbon source of GSB is carbon dioxide, which is assimilated through the reverse tricarboxylic acid cycle. Our review provides a thorough introduction to the comparative eco-physiology of GSB and discusses selected application possibilities of anoxygenic phototrophs in the fields of environmental management, bioremediation, and biotechnology.
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BACKGROUND: Available descriptive studies on equine pneumonia are outdated or focus on specific horse or bacterial populations. OBJECTIVES: To describe the clinical presentation and bacterial isolates of adult horses with bacterial pneumonia and identify factors associated with death. ANIMALS: One hundred sixteen horses >2 years old with bacterial pneumonia. METHODS: Retrospective case series. Data regarding history, physical examination, clinicopathologic features, treatment, bacterial culture and sensitivity, and outcome were collected and analyzed retrospectively. RESULTS: Historical risk factors were present for 60% of cases, whereas abnormal vital signs on intake were present for <50%. Most horses (58%) underwent at least 1 change of antimicrobial treatment, and 67% received the highest-priority critically important antimicrobials. Streptococcus zooepidemicus was the most isolated bacteria (44%), followed by Escherichia coli (19%), Klebsiella spp. (18%), other Streptococcus species (17%), and Bacillus spp. (13%). Fusobacterium spp. were the most common anaerobic isolates (11%). Antimicrobial susceptibility varied widely. Survival to discharge was 73%. Heart rate at presentation (odds ratio [OR] 1.08, 95% confidence interval [CI] 1.008-1.17, P = .03) and higher creatinine (OR 14.1, 95% CI 1.56-127.6, P = .02) increased the risk of death. Higher lymphocyte count (OR 0.27, 95% CI 0.08-0.94, P = .04) reduced risk. CONCLUSIONS AND CLINICAL IMPORTANCE: Contrasting older literature, Fusobacterium spp. were the most common anaerobes. Streptococcus zooepidemicus remained the most common isolate and was predictably susceptible to penicillin. Antimicrobial susceptibility was otherwise variable and broad applicability is limited as this was a single-center study. Increased risk of death associated with tachycardia and abnormally high serum creatinine concentration is consistent with previous studies.
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Oral Veillonella species are among the early colonizers of the human oral cavity. We constructed a small, single-selectable-marker shuttle plasmid, examined its ability to be transformed into diverse oral Veillonella strains, and assessed its potential use for expressing a gene encoding an oxygen-independent fluorescent protein, thus generating a fluorescent Veillonella parvula strain. Because tetracycline resistance is common in Veillonella, we replaced genes encoding ampicillin- and tetracycline-resistance in a previously described shuttle plasmid (pBSJL2) with a chloramphenicol acetyltransferase gene. The resulting plasmid pCF1135 was successfully introduced into four strains representing V. parvula and V. atypica by either natural transformation or electroporation. We then modified this plasmid to express a gene encoding an oxygen-independent fluorescent protein in V. parvula SKV38. The resulting strain yielded a fluorescence signal intensity â¼16 times higher than the wild type in microplate-based fluorimetry experiments. While fluorescence microscopy demonstrated that planktonic cells, colonies, and biofilms of fluorescent V. parvula could also be imaged, photobleaching was a significant issue. In conclusion, we anticipate this genetic system and information provided here will facilitate expanded studies of oral Veillonella species' properties and behavior.
Subject(s)
Mouth , Plasmids , Veillonella , Plasmids/genetics , Veillonella/genetics , Humans , Mouth/microbiology , Fluorescence , Biofilms/growth & development , Luminescent Proteins/genetics , Genetic Vectors , Electroporation , Microscopy, Fluorescence , Tetracycline Resistance/geneticsABSTRACT
Members of the mammalian gut microbiota metabolize diverse complex carbohydrates that are not digested by the host, which are collectively labeled "dietary fiber." While the enzymes and transporters that each strain uses to establish a nutrient niche in the gut are often exquisitely specific, the relationship between carbohydrate structure and microbial ecology is imperfectly understood. The present study takes advantage of recent advances in complex carbohydrate structure determination to test the effects of fiber monosaccharide composition on microbial fermentation. Fifty-five fibers with varied monosaccharide composition were fermented by a pooled feline fecal inoculum in a modified MiniBioReactor array system over a period of 72 hours. The content of the monosaccharides glucose and xylose was significantly associated with the reduction of pH during fermentation, which was also predictable from the concentrations of the short-chain fatty acids lactic acid, propionic acid, and the signaling molecule indole-3-acetic acid. Microbiome diversity and composition were also predictable from monosaccharide content and SCFA concentration. In particular, the concentrations of lactic acid and propionic acid correlated with final alpha diversity and were significantly associated with the relative abundance of several of the genera, including Lactobacillus and Dubosiella. Our results suggest that monosaccharide composition offers a generalizable method to compare any dietary fiber of interest and uncover links between diet, gut microbiota, and metabolite production. IMPORTANCE: The survival of a microbial species in the gut depends on the availability of the nutrients necessary for that species to survive. Carbohydrates in the form of non-host digestible fiber are of particular importance, and the set of genes possessed by each species for carbohydrate consumption can vary considerably. Here, differences in the monosaccharides that are the building blocks of fiber are considered for their impact on both the survival of different species of microbes and on the levels of microbial fermentation products produced. This work demonstrates that foods with similar monosaccharide content will have consistent effects on the survival of microbial species and on the production of microbial fermentation products.
Subject(s)
Bacteria , Dietary Fiber , Fermentation , Gastrointestinal Microbiome , Monosaccharides , Dietary Fiber/metabolism , Monosaccharides/metabolism , Monosaccharides/analysis , Animals , Bacteria/classification , Bacteria/metabolism , Bacteria/genetics , Feces/microbiology , Feces/chemistry , Fatty Acids, Volatile/metabolismABSTRACT
Various environmental factors, including H2 availability, metabolic tradeoffs, optimal growth temperature, stochasticity, and hydrology, were examined to determine if they affect microbial competition between three autotrophic thermophiles. The thiosulfate reducer Desulfurobacterium thermolithotrophum (Topt72°C) was grown in mono- and coculture separately with the methanogens Methanocaldococcus jannaschii (Topt82°C) at 72°C and Methanothermococcus thermolithotrophicus (Topt65°C) at 65°C at high and low H2 concentrations. Both methanogens showed a metabolic tradeoff shifting from high growth rate-low cell yield at high H2 concentrations to low growth rate-high cell yield at low H2 concentrations and when grown in coculture with the thiosulfate reducer. In 1:1 initial ratios, D. thermolithotrophum outcompeted both methanogens at high and low H2, no H2S was detected on low H2, and it grew with only CO2 as the electron acceptor indicating a similar metabolic tradeoff with low H2. When the initial methanogen-to-thiosulfate reducer ratio varied from 1:1 to 104:1 with high H2, D. thermolithotrophum always outcompeted M. jannaschii at 72°C. However, M. thermolithotrophicus outcompeted D. thermolithotrophum at 65°C when the ratio was 103:1. A reactive transport model that mixed pure hydrothermal fluid with cold seawater showed that hyperthermophilic methanogens dominated in systems where the residence time of the mixed fluid above 72°C was sufficiently high. With shorter residence times, thermophilic thiosulfate reducers dominated. If residence times increased with decreasing fluid temperature along the flow path, then thermophilic methanogens could dominate. Thermophilic methanogen dominance spread to previously thiosulfate-reducer-dominated conditions if the initial ratio of thermophilic methanogen-to-thiosulfate reducer increased. IMPORTANCE: The deep subsurface is the largest reservoir of microbial biomass on Earth and serves as an analog for life on the early Earth and extraterrestrial environments. Methanogenesis and sulfur reduction are among the more common chemolithoautotrophic metabolisms found in hot anoxic hydrothermal vent environments. Competition between H2-oxidizing sulfur reducers and methanogens is primarily driven by the thermodynamic favorability of redox reactions with the former outcompeting methanogens. This study demonstrated that competition between the hydrothermal vent chemolithoautotrophs Methanocaldococcus jannaschii, Methanothermococcus thermolithotrophicus, and Desulfurobacterium thermolithotrophum is also influenced by other overlapping factors such as staggered optimal growth temperatures, stochasticity, and hydrology. By modeling all aspects of microbial competition coupled with field data, a better understanding is gained on how methanogens can outcompete thiosulfate reducers in hot anoxic environments and how the deep subsurface contributes to biogeochemical cycling.
Subject(s)
Chemoautotrophic Growth , Hydrogen , Hydrothermal Vents , Hydrothermal Vents/microbiology , Hydrogen/metabolism , Seawater/microbiology , Deltaproteobacteria/metabolism , Deltaproteobacteria/growth & development , Methanocaldococcus/metabolism , Methanocaldococcus/growth & development , Methanobacteriaceae/metabolism , Methanobacteriaceae/growth & development , Hot TemperatureABSTRACT
Lymph nodes (LN) harboring bacteria, when being incorporated into ground beef, may impact the microbial safety and quality of such products. We tested two main foodborne pathogens Salmonella and Shiga toxin-producing Escherichia coli (STEC) and profiled the microbiota in LNs (n = 160) of cattle harvested at a Canadian abattoir, by conventional plating methods, PCR, and high throughput sequencing. LNs at two anatomical locations, subiliac and popliteal from 80 cattle were included. All cattle had bacteria detected in popliteal and/or subiliac LNs with the maximum bacterial load of 5.4 and 2.8 log10CFU/g in popliteal and subiliac LNs, respectively. Neither Salmonella nor STEC was found in LNs although STEC was detected in a significant percentage of samples from beef hides (50.6 %) by plating and/or PCR. Both 16S rRNA gene amplicon and metagenome sequencing found the predominance of Escherichia (13-34.6 % among bacterial community), Clostridium (12.6-20.6 %) and Streptococcus (9.7-10 %) in popliteal LNs. Metagenomic sequencing was able to identify the predominant taxa at species level with E. coli (13 %), Clostridium perfringens (11.1 %) and Streptococcus uberis (6 %) predominant in LNs. Low prevalence/abundance of Salmonella was found by metagenomic sequencing. In conclusion, the relatively high bacterial load and diversity in LNs may affect the shelf life of ground beef and high relative abundance of E. coli would warrant further monitoring.
Subject(s)
Abattoirs , Lymph Nodes , Microbiota , RNA, Ribosomal, 16S , Salmonella , Shiga-Toxigenic Escherichia coli , Animals , Cattle , Canada , Lymph Nodes/microbiology , RNA, Ribosomal, 16S/genetics , Shiga-Toxigenic Escherichia coli/isolation & purification , Shiga-Toxigenic Escherichia coli/genetics , Salmonella/isolation & purification , Salmonella/genetics , Salmonella/classification , Red Meat/microbiology , Food MicrobiologyABSTRACT
Transitioning away from fossil feedstocks is imperative to mitigate climate change, and necessitates the utilization of renewable, alternative carbon and energy sources to foster a circular carbon economy. In this context, lignocellulosic biomass and one-carbon compounds emerge as promising feedstocks that could be renewably upgraded by thermophilic anaerobes (thermoanaerobes) via gas fermentation or consolidated bioprocessing to value-added products. In this review, the potential of thermoanaerobes for cost-efficient, effective and sustainable bioproduction is discussed. Metabolic and bioprocess engineering approaches are reviewed to draw a comprehensive picture of current developments and future perspectives for the conversion of renewable feedstocks to chemicals and fuels of interest. Selected bioprocessing scenarios are outlined, offering practical insights into the applicability of thermoanaerobes at a large scale. Collectively, the potential advantages of thermoanaerobes regarding process economics could facilitate an easier transition towards sustainable bioprocesses with renewable feedstocks.
Subject(s)
Biotechnology , Carbon , Biotechnology/methods , Fermentation , Biomass , Lignin/metabolism , Biofuels , Thermoanaerobacter/metabolismABSTRACT
The gut microbiota has been implicated as a driver of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Recently we described, mucosal biofilms, signifying alterations in microbiota composition and bile acid (BA) metabolism in IBS and ulcerative colitis (UC). Luminal oxygen concentration is a key factor in the gastrointestinal (GI) ecosystem and might be increased in IBS and UC. Here we analyzed the role of archaea as a marker for hypoxia in mucosal biofilms and GI homeostasis. The effects of archaea on microbiome composition and metabolites were analyzed via amplicon sequencing and untargeted metabolomics in 154 stool samples of IBS-, UC-patients and controls. Mucosal biofilms were collected in a subset of patients and examined for their bacterial, fungal and archaeal composition. Absence of archaea, specifically Methanobrevibacter, correlated with disrupted GI homeostasis including decreased microbial diversity, overgrowth of facultative anaerobes and conjugated secondary BA. IBS-D/-M was associated with absence of archaea. Presence of Methanobrevibacter correlated with Oscillospiraceae and epithelial short chain fatty acid metabolism and decreased levels of Ruminococcus gnavus. Absence of fecal Methanobrevibacter may indicate a less hypoxic GI environment, reduced fatty acid oxidation, overgrowth of facultative anaerobes and disrupted BA deconjugation. Archaea and Ruminococcus gnavus could distinguish distinct subtypes of mucosal biofilms. Further research on the connection between archaea, mucosal biofilms and small intestinal bacterial overgrowth should be performed.
Subject(s)
Archaea , Bacteria , Biofilms , Feces , Gastrointestinal Microbiome , Humans , Biofilms/growth & development , Archaea/classification , Archaea/metabolism , Archaea/genetics , Archaea/isolation & purification , Adult , Middle Aged , Female , Male , Bacteria/classification , Bacteria/genetics , Bacteria/metabolism , Bacteria/isolation & purification , Feces/microbiology , Colon/microbiology , Methanobrevibacter/metabolism , Methanobrevibacter/genetics , Methanobrevibacter/growth & development , Methanobrevibacter/isolation & purification , Colitis, Ulcerative/microbiology , Colitis, Ulcerative/metabolism , Irritable Bowel Syndrome/microbiology , Irritable Bowel Syndrome/metabolism , Aged , Intestinal Mucosa/microbiology , Intestinal Mucosa/metabolism , Ileum/microbiology , Fatty Acids, Volatile/metabolism , Young Adult , Bile Acids and Salts/metabolismABSTRACT
Slackia exigua, originally classified as Eubacterium exiguum, is a Gram-positive, asaccharolytic, rod-shaped anaerobic bacterium. The virulence factors of S. exigua have not been accurately identified. The objective of the study is to evaluate the pathogenic potential of S. exigua by presenting the cases of infections diagnosed at our hospital laboratory. Additionally, we reviewed the literature to summarize the experience with S. exigua infections to clarify, in the light of current knowledge, the clinical picture, diagnostic, and therapeutic issues related to this anaerobic bacterium. We reported eleven severe human infections caused by S. exigua. All patients required hospitalization. Nine of the cases involved chronic infections in the stomatognathic system, in two patients, skin infections were diagnosed. As it is known, S. exigua is a component of the human microbiota; however, it can cause opportunistic infections, particularly in the case of translocation outside its natural habitat. A critical literature analysis revealed that S. exigua can be responsible for bacteremia, meningitis, tissue necrosis, periprosthetic joint infection, and osteomyelitis. Several studies have been published regarding the determination of drug susceptibility of S. exigua. The isolated strains were susceptible to most antibiotics used for the treatment of anaerobic infections. The interpretation of antimicrobial susceptibility testing for some slow-growing in vitro, infrequently causing infections anaerobic bacteria, such as S. exigua, is based on The European Committee on Antimicrobial Susceptibility Testing (EUCAST) additional guidance taking into account the determination of drug susceptibility for groups of microorganisms for which cut-off values have not been developed.
Subject(s)
Anti-Bacterial Agents , Humans , Female , Male , Middle Aged , Adult , Anti-Bacterial Agents/therapeutic use , Aged , Gram-Positive Bacterial Infections/drug therapy , Gram-Positive Bacterial Infections/diagnosis , Gram-Positive Bacterial Infections/microbiology , PolandABSTRACT
Two thermophilic spore-forming sulfate-reducing strains, 435T and 781, were isolated from oil and gas reservoirs in Western Siberia (Russia) about 50 years ago. Both strains were found to be neutrophilic, chemoorganotrophic, anaerobic bacteria, growing at 45-70 °C (optimum, 55-60 °C) and with 0-4.5% (w/v) NaCl (optimum, 0.5-1% NaCl). The major fatty acids were iso-C15:0, iso-C17:0, C16:0, and C18:0. In sulfate-reducing conditions, the strains utilized H2/CO2, formate, lactate, pyruvate, malate, fumarate, succinate, methanol, ethanol, propanol, butanol, butyrate, valerate, and palmitate. In 2005, based on phenotypic characteristics and a 16S rRNA gene sequence analysis, the strains were described as 'Desulfotomaculum salinum' sp. nov. However, this species was not validly published because the type strain was not deposited in two culture collections. In this study, a genomic analysis of strain 435T was carried out to determine its taxonomic affiliation. The genome size of strain 435T was 2.886 Mb with a 55.1% genomic G + C content. The average nucleotide identity and digital DNA-DNA hybridization values were highest between strain 435T and members of the genus Desulfofundulus, 78.7-93.3% and 25.0-52.2%, respectively; these values were below the species delineation cut-offs (<95-96% and <70%). The cumulative phenotypic and phylogenetic data indicate that two strains represent a novel species within the genus Desulfofundulus, for which the name Desulfofundulus salinus sp. nov. is proposed. The type strain is 435T (=VKM B-1492T = DSM 23196T). A genome analysis of strain 435T revealed the genes for dissimilatory sulfate reduction, autotrophic carbon fixation via the Wood-Ljungdahl pathway, hydrogen utilization, methanol and organic acids metabolism, and sporulation, which were confirmed by cultivation studies.
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Bacterial isolates from the human urinary microbiome have been extensively studied for their antibiotic resistance; however, little work has been done on those isolates that are difficult to grow in vitro. This study was designed to qualify a serum-based medium, New York City Broth III (NYCIII), and a broth microdilution method to determine the antibiotic susceptibility of previously underreported or undescribed microbes that have a difficult time growing in standard Mueller-Hinton broth. Here, we demonstrate that NYCIII microbroth dilution can be an effective method for the determination of antibiotic susceptibility of species found in the human urinary microbiome. We show that this method serves well to characterize fastidious and anaerobic urinary microbes that have no Clinical and Laboratory Standards Institute (CLSI) guidelines, including several in the families Aerococcaceae, Lactobacillaceae, or Actinomycetaceae. Previous studies using expanded quantitative urine culture reveal that urine samples from clinical patients are commonly polymicrobial in composition. Thus, we test whether NYCIII can serve as a viable harmonized medium, capable of supporting antibiotic susceptibility testing in a range of fastidious, non-fastidious, and anaerobic urinary microbes. We propose this methodology to be standardized comparable to CLSI standards to allow for resistance testing in uncharacterized urinary bacteria. IMPORTANCE: Antibiotic susceptibilities of fastidious and anaerobic bacteria of the human urinary microbiome are largely underreported due to difficulty in growing them in the lab environment. The current standard medium, Muller-Hinton broth, has difficulty supporting the growth of many of these species, leaving microbiologists without a standardized method. To address this need, this study offers a methodology to survey susceptibilities in a high-throughput manner of these understudied microbes with a proposed harmonized medium, NYCIII, which is capable of supporting the growth of both fastidious and non-fastidious urinary microbes. Broader standardization of this method can allow for the development of antibiotic-resistant breakpoints of the many uncharacterized urinary microbes.
Subject(s)
Anti-Bacterial Agents , Bacteria, Anaerobic , Microbial Sensitivity Tests , Microbiota , Humans , Microbial Sensitivity Tests/methods , Anti-Bacterial Agents/pharmacology , Microbiota/drug effects , Bacteria, Anaerobic/drug effects , Bacteria, Anaerobic/isolation & purification , Urine/microbiology , Urinary Tract Infections/microbiology , Bacteria/drug effects , Bacteria/isolation & purification , Bacteria/growth & development , Culture Media/chemistryABSTRACT
SUMMARYDiabetic foot infections (DFI) are a public health problem worldwide. DFI are polymicrobial, biofilm-associated infections involving complex bacterial communities organized in functional equivalent pathogroups, all including anaerobes. Indeed, multiple pathophysiological factors favor the growth of anaerobes in this context. However, the prevalence, role, and contribution of anaerobes in wound evolution remain poorly characterized due to their challenging detection. Studies based on culture reviewed herein showed a weighted average of 17% of patients with anaerobes. Comparatively, the weighted average of patients with anaerobes identified by 16S rRNA gene sequencing was 83.8%. Culture largely underestimated not only the presence but also the diversity of anaerobes compared with cultivation-independent approaches but both methods showed that anaerobic Gram-negative bacilli and Gram-positive cocci were the most commonly identified in DFI. Anaerobes were more present in deeper lesions, and their detection was associated with fever, malodorous lesions, and ulcer depth and duration. More specifically, initial abundance of Peptoniphilus spp. was associated with ulcer-impaired healing, Fusobacterium spp. detection was significantly correlated with the duration of DFI, and the presence of Bacteroides spp. was significantly associated with amputation. Antimicrobial resistance of anaerobes in DFI remains slightly studied and warrants more consideration in the context of increasing resistance of the most frequently identified anaerobes in DFI. The high rate of patients with DFI-involving anaerobes, the increased knowledge on the species identified, their virulence factors, and their potential role in wound evolution support recommendations combining debridement and antibiotic therapy effective on anaerobes in moderate and severe DFI.
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PURPOSE: Despite the importance of abscess lesions in clinical decisions regarding anaerobic bacteremia (AB), their impact on clinical characteristics remains unclear. Herein, we aimed to elucidate the clinical factors associated with AB that were unaccompanied by detectable abscess lesions during the initial phase of infection. METHODS: This was a multicenter retrospective observational study involving patients with culture-proven AB at six tertiary hospitals in Japan between January 2012 and March 2022. Data on clinical characteristics, laboratory and radiological findings were collected, and their associations with the absence of detectable abscess lesions were analyzed. RESULTS: In total, 393 participants were included. Abscess lesions were absent in 42.7% of the entire cohort and detectable in the remaining patients. No differences were identified in the malignancy, severity, or 30-day mortality between patients with and without detectable abscess lesions. Multivariate logistic regression analysis adjusted for age and the modified Charlson comorbidity score revealed that the immunosuppressive status (febrile neutropenia or corticosteroid use), C-reactive protein (CRP) level ≤9.8 mg/dL at onset, and the presence of gram-positive anaerobic rods (GPARs) were independently associated with AB unaccompanied by detectable abscess lesions [odds ratios (ORs) 3.24, 3.00, and 2.81, respectively; p < 0.05]. CONCLUSION: This study elucidated distinctive clinical and microbiological characteristics of AB unaccompanied by detectable abscess lesions, with relatively lower CRP elevation, immunosuppressive status, and GPARs as the causative anaerobes.
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Black pigmented gram negative anaerobes are associated with periodontal disease and tooth loss. Therefore, it is of interest to evaluate the antimicrobial activity of Ocimum Sanctum.L (Tulsi) gel against black pigmented anaerobes. Plaque samples were collected from the subject and kept in anaerobic broth for 4 hours of incubation at 37°C. 50µL concentration of Tulsi gel was added and kept in gas pack system for 3-5 days. Zone of inhibition was measured. Ocimum sanctum L. (Tulsi) exhibits strong antibacterial activity against Black Pigmented bacteroides at 1% and 2%.Tulasi gel was effective at higher concentrations, indicating the possibility of using it as an adjunct to standard periodontal treatment.
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Background: Intravenous drug users (IDUs) have a high risk of developing skin and soft tissue infections such as erysipelas, abscesses, and less frequently necrotizing fasciitis (NF) or gas gangrene. Rarely, the cause of the infection is microorganisms residing in the oral cavity and can lead to life-threatening infections. Methods: We describe the case of a 43-year-old man intravenous drug user (IDU) who was admitted for intense leg pain following an injection of cocaine at that site. Results: A clinical and radiological diagnosis of NF was made, so the patient was started on empirical antibiotic therapy and underwent surgical fasciotomy (after 8 hours from admission). Prevotella denticola was isolated from multiple intraoperative specimens and was resistant to initial antimicrobial therapy. The man, suffering from periodontal disease, reported sucking the syringe several times to unblock it. Both fasciotomy surgery and adjustment of antimicrobial therapy enabled therapeutic success. Conclusions: In IDUs the risk of deep skin and soft tissue infections is high and may be aggravated by contamination with oral microorganisms. The choice of empirical antibiotic treatment should include agents active against oral cavity anaerobes, such as P. denticola.
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Hidradenitis suppurativa (HS), or acne inversa, is a chronic inflammatory dermatological condition characterized by painful and recurrent nodules and purulent abscesses. HS can have a devastating impact on the quality of life of patients. This condition is commonly localized to the axilla, groin, perineal, and inframammary regions, and can develop fistulas and sinus tracts over time. Its pathogenesis remains elusive and is best characterized at the moment as multi-factorial. Additionally, questions remain about the role of cutaneous dysbiosis as a primary HS trigger or as a secondary perturbation due to HS inflammation. This article features works in relation to HS and its interplay with bacterial microflora. We address current treatment approaches and their impact on HS-related bacteria, as well as areas of therapeutic innovation. In the future, disease-modifying or remittive therapy will likely combine an advanced/targeted anti-inflammatory approach with one that effectively modulates cutaneous and deep tissue dysbiosis.
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Here, we report the complete genome sequence of Aminobacterium sp. strain MB27-C1, which was isolated from sewage sludge collected at the wastewater treatment plant of Sanming Steel Co. Ltd. in Fujian, China. The resulting genome of strain MB27-C1 is a single contig of 2,427,830 bp with 41.58% GC content.
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The family Fusobacteriaceae is a large family within the phylum Fusobacteriota. The reclassification of F. naviforme as Zandiella naviformis gen. nov., comb. nov. is proposed because of the separate and distinct phylogenetic situation on the basis of the results of 16S rRNA gene sequence analysis, the genetic and genomic differences from all other species and subspecies in the Fusobacteriaceae family. The type strain is ATCC 25832; CCUG 50052; NCTC 13121. In phylogenetic trees drawn using complete genome sequences and 16S rRNA gene sequences, F. necrophorum subsp. funduliforme and F. equinum were clades together with F. necrophorum subsp. necrophorum and F. gonidiaformans, respectively. The average nucleotide identity, average amino acid identity, and digital DNA-DNA hybridization values between themes exceeded the cut-off values for species delineation. Based on these results, F. necrophorum subsp. funduliforme and F. equinum should be reclassified as later heterotypic synonyms of F. necrophorum subsp. necrophorum and F. gonidiaformans, respectively.