RESUMEN
Genome-encoded antibiotic resistance (ARE) ATP-binding cassette (ABC) proteins of the F subfamily (ARE-ABCFs) mediate intrinsic resistance in diverse Gram-positive bacteria. The diversity of chromosomally-encoded ARE-ABCFs is far from being fully experimentally explored. Here we characterise phylogenetically diverse genome-encoded ABCFs from Actinomycetia (Ard1 from Streptomyces capreolus, producer of the nucleoside antibiotic A201A), Bacilli (VmlR2 from soil bacterium Neobacillus vireti) and Clostridia (CplR from Clostridium perfringens, Clostridium sporogenes and Clostridioides difficile). We demonstrate that Ard1 is a narrow spectrum ARE-ABCF that specifically mediates self-resistance against nucleoside antibiotics. The single-particle cryo-EM structure of a VmlR2-ribosome complex allows us to rationalise the resistance spectrum of this ARE-ABCF that is equipped with an unusually long antibiotic resistance determinant (ARD) subdomain. We show that CplR contributes to intrinsic pleuromutilin, lincosamide and streptogramin A resistance in Clostridioides, and demonstrate that C. difficile CplR (CDIF630_02847) synergises with the transposon-encoded 23S ribosomal RNA methyltransferase Erm to grant high levels of antibiotic resistance to the C. difficile 630 clinical isolate. Finally, assisted by uORF4u, our novel tool for detection of upstream open reading frames, we dissect the translational attenuation mechanism that controls the induction of cplR expression upon an antibiotic challenge.
Asunto(s)
Antibacterianos , Farmacorresistencia Bacteriana , Genes Bacterianos , Bacterias Grampositivas , Antibacterianos/farmacología , Antibacterianos/química , Clostridioides difficile/efectos de los fármacos , Clostridioides difficile/genética , Bacterias Grampositivas/efectos de los fármacos , Bacterias Grampositivas/genética , Nucleósidos/química , Nucleósidos/farmacología , Farmacorresistencia Bacteriana/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Genes Bacterianos/genética , Clostridium/efectos de los fármacos , Clostridium/genética , Microscopía por CrioelectrónRESUMEN
Clostridium botulinum is a foodborne pathogen responsible for severe neuroparalytic disease associated with the ingestion of pre-formed toxin in food, with processed meats and canned foods being the most affected. Control of this pathogen in meat products is carried out using the preservative sodium nitrite (NaNO2), which in food, under certain conditions, such as thermal processing and storage, can form carcinogenic compounds. Therefore, the objective was to use nanoemulsified essential oils (EOs) as natural antimicrobial agents, with the aim of reducing the dose of NaNO2 applied in mortadella. The antimicrobial activity of nanoemulsions prepared with mixtures of EOs of garlic, clove, pink pepper, and black pepper was evaluated on endospores and vegetative cells of C. botulinum and Clostridium sporogenes (surrogate model) inoculated in mortadella prepared with 50 parts per million NaNO2. The effects on the technological (pH, water activity, and color) and sensory characteristics of the product were also evaluated. The combinations of EOs and their nanoemulsions showed sporicidal effects on the endospores of both tested microorganisms, with no counts observed from the 10th day of analysis. Furthermore, bacteriostatic effects on the studied microorganisms were observed. Regarding the technological and sensorial characteristics of the product, the addition of the combined EOs had a negative impact on the color of the mortadella and on the flavor/aroma. Despite the strong commercial appeal of adding natural preservatives to foods, the effects on flavor and color must be considered. Given the importance of controlling C. botulinum in this type of product, as well as the reduction in the amount of NaNO2 used, this combination of EOs represents a promising antimicrobial alternative to this preservative, encouraging further research in this direction.
Asunto(s)
Clostridium botulinum , Clostridium , Productos de la Carne , Aceites Volátiles , Aceites Volátiles/farmacología , Clostridium botulinum/efectos de los fármacos , Productos de la Carne/microbiología , Clostridium/efectos de los fármacos , Microbiología de Alimentos , Nitrito de Sodio/farmacología , Emulsiones , Humanos , Conservación de Alimentos/métodos , Esporas Bacterianas/efectos de los fármacos , Conservantes de Alimentos/farmacología , Gusto , Antibacterianos/farmacologíaRESUMEN
Amino acid-fermenting Clostridia have undesirable effects in agricultural systems, which can be mitigated by antibiotics, but resistance necessitates alternatives. Here, we demonstrate the efficacy of cannabidiol on growth and ammonia inhibition of five agriculturally relevant Clostridia: Clostridium sporogenes, Peptostreptococcus spp., Clostridioides difficile, Acetoanaerobium sticklandii, and Clostridium aminophilum.
Asunto(s)
Antibacterianos , Cannabidiol , Clostridium , Cannabidiol/farmacología , Antibacterianos/farmacología , Clostridium/efectos de los fármacos , Clostridium/crecimiento & desarrollo , Amoníaco/metabolismoRESUMEN
Clostridium sporogenes has been widely used as a surrogate for proteolytic C. botulinum for validating thermal processes in low-acid cans. To limit the intensity of heat treatments, industrials must use other ways of control as an association of acidic and saline environment after a low heat treatment. The probability of growth of pH (7-4.4), sodium chloride concentration (0-11%) and heat treatment (80°C-10 min; 100°C-1.5 min and 5.2 min) were studied on C. sporogenes PA 3679 spores and vegetative cells. Vegetative cells or heat-treated spores were inoculated in PYGm broth at 30 °C for 48 days in anaerobic conditions. Vegetative cells growth (pH 4.6-pH 4.5; 7%-8% NaCl) range is larger than the spore one (pH 5.2-pH 5.0; 6%-7% NaCl). Spores germination and outgrowth rage is decreased if the spores are heat-treated at 100 °C for 1.5 min (pH 5.5-5.3; 4%-5% NaCl) and 5.2 min (pH 5.7-5.3; 4%-5% NaCl). The C. sporogenes PA 3679 spores germination and outgrowth is impacted by their physiological state. The synergic interaction between environmental factors (pH and NaCl) and the physiological state (vegetative cells and spores) opening new possibilities for optimizing food formulation processes to manage the risks of C. sporogenes spoilage.
Asunto(s)
Clostridium/crecimiento & desarrollo , Conservación de Alimentos/métodos , Alimentos en Conserva/microbiología , Cloruro de Sodio/farmacología , Esporas Bacterianas/crecimiento & desarrollo , Clostridium/efectos de los fármacos , Clostridium botulinum/efectos de los fármacos , Clostridium botulinum/crecimiento & desarrollo , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Conservación de Alimentos/instrumentación , Calor , Concentración de Iones de Hidrógeno , Viabilidad Microbiana , Cloruro de Sodio/análisisRESUMEN
Clostridium ventriculi (syn. Sarcina ventriculi) is a Gram-positive opportunistic pathogen with sarcina morphology. In the case of gastrointestinal disorders, the treatment is often empirical. Due to the common occurrence in primates and the potential risk of dysbiosis; the antibiotic susceptibility screening of C. ventriculi strains isolated from guenon monkeys and crested gibbons to 58 antibiotics was performed to reduce potentially ineffective antibiotic use in case of disease. Isolates were found to be susceptible to the majority of the tested antibiotics, mainly to (fluoro)quinolones, macrolides, penicillins, and tetracyclines. The susceptibility profiles were similar despite the hosts. Tested strains showed also natural resistance to a few antibiotics on the genus level. Detected in vitro antibiotic efficiency is consistent with documented human treatment cases.
Asunto(s)
Antibacterianos/uso terapéutico , Infecciones por Clostridium/diagnóstico , Infecciones por Clostridium/tratamiento farmacológico , Clostridium/efectos de los fármacos , Clostridium/genética , Primates/microbiología , Animales , Variación Genética , Genotipo , Haplorrinos/microbiología , Hylobates/microbiologíaRESUMEN
Clostridium botulinum is a Gram-positive, anaerobic, spore-forming bacterium capable of producing botulinum toxin and responsible for botulism of humans and animals. Phage-encoded enzymes called endolysins, which can lyse bacteria when exposed externally, have potential as agents to combat bacteria of the genus Clostridium. Bioinformatics analysis revealed in the genomes of several Clostridium species genes encoding putative N-acetylmuramoyl-l-alanine amidases with anti-clostridial potential. One such enzyme, designated as LysB (224-aa), from the prophage of C. botulinum E3 strain Alaska E43 was chosen for further analysis. The recombinant 27,726 Da protein was expressed and purified from E. coli Tuner(DE3) with a yield of 37.5 mg per 1 L of cell culture. Size-exclusion chromatography and analytical ultracentrifugation experiments showed that the protein is dimeric in solution. Bioinformatics analysis and results of site-directed mutagenesis studies imply that five residues, namely H25, Y54, H126, S132, and C134, form the catalytic center of the enzyme. Twelve other residues, namely M13, H43, N47, G48, W49, A50, L73, A75, H76, Q78, N81, and Y182, were predicted to be involved in anchoring the protein to the lipoteichoic acid, a significant component of the Gram-positive bacterial cell wall. The LysB enzyme demonstrated lytic activity against bacteria belonging to the genera Clostridium, Bacillus, Staphylococcus, and Deinococcus, but did not lyse Gram-negative bacteria. Optimal lytic activity of LysB occurred between pH 4.0 and 7.5 in the absence of NaCl. This work presents the first characterization of an endolysin derived from a C. botulinum Group II prophage, which can potentially be used to control this important pathogen.
Asunto(s)
Clostridium botulinum tipo E/enzimología , Endopeptidasas/metabolismo , N-Acetil Muramoil-L-Alanina Amidasa/metabolismo , Secuencia de Aminoácidos , Dominio Catalítico , Clostridium/efectos de los fármacos , Clostridium/ultraestructura , Endopeptidasas/química , Endopeptidasas/aislamiento & purificación , Endopeptidasas/farmacología , Lipopolisacáridos/metabolismo , Pruebas de Sensibilidad Microbiana , N-Acetil Muramoil-L-Alanina Amidasa/química , N-Acetil Muramoil-L-Alanina Amidasa/aislamiento & purificación , N-Acetil Muramoil-L-Alanina Amidasa/farmacología , Profagos/enzimología , Ácidos Teicoicos/metabolismoRESUMEN
Five bacterial (facultatively) anaerobic strains, namely Buttiauxella sp. MASE-IM-9, Clostridium sp. MASE-IM-4, Halanaerobium sp. MASE-BB-1, Trichococcus sp. MASE-IM-5, and Yersinia intermedia MASE-LG-1 isolated from different extreme natural environments were subjected to Mars relevant environmental stress factors in the laboratory under controlled conditions. These stress factors encompassed low water activity, oxidizing compounds, and ionizing radiation. Stress tests were performed under permanently anoxic conditions. The survival rate after addition of sodium perchlorate (Na-perchlorate) was found to be species-specific. The inter-comparison of the five microorganisms revealed that Clostridium sp. MASE-IM-4 was the most sensitive strain (D10-value (15 min, NaClO4) = 0.6 M). The most tolerant microorganism was Trichococcus sp. MASE-IM-5 with a calculated D10-value (15 min, NaClO4) of 1.9 M. Cultivation in the presence of Na-perchlorate in Martian relevant concentrations up to 1 wt% led to the observation of chains of cells in all strains. Exposure to Na-perchlorate led to a lowering of the survival rate after desiccation. Consecutive exposure to desiccating conditions and ionizing radiation led to additive effects. Moreover, in a desiccated state, an enhanced radiation tolerance could be observed for the strains Clostridium sp. MASE-IM-4 and Trichococcus sp. MASE-IM-5. These data show that anaerobic microorganisms from Mars analogue environments can resist a variety of Martian-simulated stresses either individually or in combination. However, responses were species-specific and some Mars-simulated extremes killed certain organisms. Thus, although Martian stresses would be expected to act differentially on microorganisms, none of the expected extremes tested here and found on Mars prevent the growth of anaerobic microorganisms.
Asunto(s)
Bacterias Anaerobias/crecimiento & desarrollo , Medio Ambiente Extraterrestre , Ambientes Extremos , Bacterias Anaerobias/efectos de los fármacos , Bacterias Anaerobias/efectos de la radiación , Carnobacteriaceae/efectos de los fármacos , Carnobacteriaceae/crecimiento & desarrollo , Carnobacteriaceae/efectos de la radiación , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Clostridium/efectos de los fármacos , Clostridium/crecimiento & desarrollo , Clostridium/efectos de la radiación , Desecación , Enterobacteriaceae/efectos de los fármacos , Enterobacteriaceae/crecimiento & desarrollo , Enterobacteriaceae/efectos de la radiación , Firmicutes/efectos de los fármacos , Firmicutes/crecimiento & desarrollo , Firmicutes/efectos de la radiación , Marte , Estrés Oxidativo , Percloratos/toxicidad , Tolerancia a Radiación , Compuestos de Sodio/toxicidad , Estrés Fisiológico/efectos de la radiación , Factores de Tiempo , Yersinia/efectos de los fármacos , Yersinia/crecimiento & desarrollo , Yersinia/efectos de la radiaciónRESUMEN
BACKGROUND: The effects of antibiotics on infant gut microbiota are unclear. We hypothesized that the use of common antibiotics results in long-term aberration in gut microbiota. METHODS: Antibiotic-naive infants were prospectively recruited when hospitalized because of a respiratory syncytial virus infection. Composition of fecal microbiota was compared between those receiving antibiotics during follow-up (prescribed at clinicians' discretion because of complications such as otitis media) and those with no antibiotic exposure. Fecal sampling started on day 1, then continued at 2-day intervals during the hospital stay, and at 1, 3 and 6 months at home. RESULTS: One hundred and sixty-three fecal samples from 40 patients (median age 2.3 months at baseline; 22 exposed to antibiotics) were available for microbiota analyses. A single course of amoxicillin or macrolide resulted in aberration of infant microbiota characterized by variation in the abundance of bifidobacteria, enterobacteria and clostridia, lasting for several months. Recovery from the antibiotics was associated with an increase in clostridia. Occasionally, antibiotic use resulted in microbiota profiles associated with inflammatory conditions. CONCLUSIONS: Antibiotic use in infants modifies especially bifidobacterial levels. Further studies are warranted whether administration of bifidobacteria will provide health benefits by normalizing the microbiota in infants receiving antibiotics.
Asunto(s)
Antibacterianos/uso terapéutico , Microbioma Gastrointestinal , Infecciones por Virus Sincitial Respiratorio/microbiología , Infecciones por Virus Sincitial Respiratorio/virología , Amoxicilina/uso terapéutico , Bifidobacterium/efectos de los fármacos , Clostridium/efectos de los fármacos , Enterobacteriaceae/efectos de los fármacos , Heces , Femenino , Biblioteca de Genes , Hospitalización , Humanos , Lactante , Recién Nacido , Inflamación , Estudios Longitudinales , Macrólidos/uso terapéutico , Masculino , Estudios ProspectivosRESUMEN
Clostridium like species, particularly Clostridium perfrigens, are the second most common causes of human anaerobic infections, including myonecrosis and bacteremia. Clostridium paraputrificum is an infrequent isolate, which has been identified in only 1% of reported cases of clostridial infections. We herein report a rare case of C. paraputrificum bacteremia in a 78-year-old Caucasian man diagnosed with an intestinal carcinoma and liver neoplastic lesions. The isolate was susceptible to chloramphenicol, meropenem, metronidazole, vancomycin, and resistant to clindamycin and penicillin, and the patient was successfully treated with metronidazole. Malignancy and inflammatory bowel diseases are often associated with clostridial bacteremia, which cannot be neglected.
Asunto(s)
Infecciones por Clostridium/diagnóstico , Infecciones por Clostridium/microbiología , Anciano , Antibacterianos/uso terapéutico , Bacteriemia/diagnóstico , Bacteriemia/tratamiento farmacológico , Bacteriemia/microbiología , Clostridium/clasificación , Clostridium/efectos de los fármacos , Clostridium/aislamiento & purificación , Infecciones por Clostridium/tratamiento farmacológico , Humanos , Enfermedades Inflamatorias del Intestino/complicaciones , Neoplasias Intestinales/complicaciones , Masculino , Pruebas de Sensibilidad Microbiana , Factores de Riesgo , Resultado del TratamientoRESUMEN
Clostridium spp. are recovered from 25% of the blood culture positive with anaerobes. However, the clinical relevance of Clostridium bacteremia has been controverted in the literature, particularly for C. perfringens. We aimed to evaluate the clinical relevance of Clostridium bacteremia, either due to C. perfringens or other Clostridium species, and to identify the risk factors of mortality in these patients. A retrospective cohort study was conducted from January 2010 to April 2018. All the patients with at least one blood culture positive with any Clostridium species were included. Eighty-one patients with a least one blood culture positive with any Clostridium species were included. Seventy patients (86.4%) fulfilled the criteria for clinically relevant bacteremia. Bacteremia due to C. perfringens tended to be less clinically relevant than other Clostridium species but this was not statistically significant (76% vs 91.2%, Pâ¯=â¯0.09). In case of clinically relevant bacteremia, the 30-day mortality rate was 31.4%. In multivariate analysis, adequate empiric antimicrobial therapy was significantly associated with survival (Pâ¯=â¯0.03). In conclusion, bacteremia due to C. perfringens or other Clostridium species is usually clinically relevant. This finding was also supported by an improved survival at 30 days when adequate empiric antimicrobial therapy was administered.
Asunto(s)
Bacteriemia , Infecciones por Clostridium , Clostridium/aislamiento & purificación , Adulto , Anciano , Antibacterianos/uso terapéutico , Bacteriemia/tratamiento farmacológico , Bacteriemia/epidemiología , Clostridium/efectos de los fármacos , Infecciones por Clostridium/tratamiento farmacológico , Infecciones por Clostridium/mortalidad , Clostridium perfringens/efectos de los fármacos , Clostridium perfringens/aislamiento & purificación , Estudios de Cohortes , Femenino , Humanos , Hipotermia/microbiología , Masculino , Persona de Mediana Edad , Mortalidad , Estudios Retrospectivos , Factores de RiesgoRESUMEN
Intestinal bacteria play an important role in bile acid metabolism and in the regulation of multiple host metabolic pathways (e.g., lipid and glucose homeostasis) through modulation of intestinal farnesoid X receptor (FXR) activity. Here, we examined the effect of berberine (BBR), a natural plant alkaloid, on intestinal bacteria using in vitro and in vivo models. In vivo, the metabolomic response and changes in mouse intestinal bacterial communities treated with BBR (100 mg/kg) for 5 days were assessed using NMR- and mass spectrometry-based metabolomics coupled with multivariate data analysis. Short-term BBR exposure altered intestinal bacteria by reducing Clostridium cluster XIVa and IV and their bile salt hydrolase (BSH) activity, which resulted in the accumulation of taurocholic acid (TCA). The accumulation of TCA was associated with activation of intestinal FXR, which can mediate bile acid, lipid, and glucose metabolism. In vitro, isolated mouse cecal bacteria were incubated with three doses of BBR (0.1, 1, and 10 mg/ml) for 4 hours in an anaerobic chamber. NMR-based metabolomics combined with flow cytometry was used to evaluate the direct physiologic and metabolic effect of BBR on the bacteria. In vitro, BBR exposure not only altered bacterial physiology but also changed bacterial community composition and function, especially reducing BSH-expressing bacteria like Clostridium spp. These data suggest that BBR directly affects bacteria to alter bile acid metabolism and activate FXR signaling. These data provide new insights into the link between intestinal bacteria, nuclear receptor signaling, and xenobiotics.
Asunto(s)
Berberina/farmacología , Microbioma Gastrointestinal/efectos de los fármacos , Mucosa Intestinal/efectos de los fármacos , Receptores Citoplasmáticos y Nucleares/metabolismo , Amidohidrolasas/metabolismo , Animales , Proteínas Bacterianas/metabolismo , Ciego/efectos de los fármacos , Ciego/metabolismo , Ciego/microbiología , Clostridium/efectos de los fármacos , Clostridium/aislamiento & purificación , Clostridium/fisiología , Microbioma Gastrointestinal/fisiología , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiología , Masculino , Metabolómica/métodos , Ratones , Ratones Endogámicos C57BL , Ácido Taurocólico/metabolismoRESUMEN
The rapid increase of antibiotic resistance has created an urgent need to develop novel antimicrobial agents. Here we describe the crystal structure of the promising bacterial target phospho-N-acetylmuramoyl-pentapeptide translocase (MraY) in complex with the nucleoside antibiotic tunicamycin. The structure not only reveals the mode of action of several related natural-product antibiotics but also gives an indication on the binding mode of the MraY UDP-MurNAc-pentapeptide and undecaprenyl-phosphate substrates.
Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/efectos de los fármacos , Clostridium/efectos de los fármacos , Transferasas/efectos de los fármacos , Tunicamicina/farmacología , Antibacterianos/química , Proteínas Bacterianas/química , Clostridium/enzimología , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Relación Estructura-Actividad , Transferasas/química , Transferasas (Grupos de Otros Fosfatos Sustitutos) , Tunicamicina/químicaRESUMEN
Today, there is no effective non-thermal method to inactivate unwanted bacterial spores in foods. High-Pressure (HP) process has been shown to act synergistically with moderate heating and the bacteriocin nisin to inactivate spores but the mechanisms have not been elucidated. The purpose of the present work was to investigate in depth the synergy of HP and nisin on various foodborne spore species and to bring new elements of understandings. For this purpose, spores of Bacillus pumilus, B. sporothermodurans, B. licheniformis, B. weihenstephanensis, and Clostridium sp. were suspended in MES buffer, in skim milk or in a liquid medium simulating cooked ham brine and treated by HP at 500â¯MPa for 10â¯minâ¯at 50⯰C or 20⯰C. Nisin (20 or 50 IU/mL) was added at three different points during treatment: during HP, during and or in the plating medium of enumeration. In the latter two cases, a high synergy was observed with the inhibition of the spores of Bacillus spp. The evaluation of the germinated fraction of Bacillus spp. spores after HP revealed that this synergy was likely due to the action of nisin on HP-sensitized spores, rather than on HP-germinated spores. Thus, the combination of nisin and HP can lead to Bacillus spp. spore inhibition at 20⯰C. And Nisin can act on HP-treated spores, even if they are not germinated. This paper provides new information about the inhibition of spores by the combination of HP and nisin. The high synergy observed at low temperature has not been reported yet and could allow food preservation without the use of any thermal process.
Asunto(s)
Presión Atmosférica , Viabilidad Microbiana/efectos de los fármacos , Nisina/farmacología , Esporas Bacterianas/efectos de los fármacos , Bacillus/efectos de los fármacos , Bacillus/crecimiento & desarrollo , Clostridium/efectos de los fármacos , Clostridium/crecimiento & desarrollo , Conservación de Alimentos , CalorRESUMEN
The continuous administration of antimicrobials in swine production has been widely criticized with the increase of antimicrobial-resistant bacteria and dysbiosis of the beneficial microbial communities. While an increasing number of studies investigate the effects of antimicrobial administration on swine gastrointestinal microbiota biodiversity, the impact of their use on the composition and diversity of nasal microbial communities has not been widely explored. The objective of this study was to characterize the short-term impact of different parenteral antibiotics administration on the composition and diversity of nasal microbial communities in growing pigs. Five antimicrobial treatment groups, each consisting of four, eight-week old piglets, were administered one of the antimicrobials; Ceftiofur Crystalline free acid (CCFA), Ceftiofur hydrochloride (CHC), Tulathromycin (TUL), Oxytetracycline (OTC), and Procaine Penicillin G (PPG) at label dose and route. Individual deep nasal swabs were collected immediately before antimicrobial administration (controlâ¯=â¯day 0), and again on days 1, 3, 7, and 14 after dosing. The nasal microbiota across all the samples were dominated by Firmicutes, proteobacteria and Bacteroidetes. While, the predominant bacterial genera were Moraxella, Clostridium and Streptococcus. Linear discriminant analysis, showed a pronounced, antimicrobial-dependent microbial shift in the composition of nasal microbiota and over time from day 0. By day 14, the nasal microbial compositions of the groups receiving CCFA and OTC had returned to a distribution that closely resembled that observed on day 0. In contrast, pigs that received CHC, TUL and PPG appeared to deviate away from the day 0 composition by day 14. Based on our results, it appears that the impact of parenteral antibiotics on the swine nasal microbiota is variable and has a considerable impact in modulating the nasal microbiota structure. Our results will aid in developing alternative strategies for antibiotics to improve swine health and consequently production.
Asunto(s)
Antiinfecciosos/farmacología , Microbiota/efectos de los fármacos , Nariz/microbiología , Porcinos/microbiología , Animales , Animales Recién Nacidos/crecimiento & desarrollo , Animales Recién Nacidos/microbiología , Antiinfecciosos/administración & dosificación , Bacteroidetes/efectos de los fármacos , Bacteroidetes/aislamiento & purificación , Cefalosporinas/farmacología , Clostridium/efectos de los fármacos , Clostridium/aislamiento & purificación , ADN Bacteriano/genética , Disacáridos/farmacología , Análisis Discriminante , Relación Dosis-Respuesta a Droga , Firmicutes/efectos de los fármacos , Firmicutes/aislamiento & purificación , Compuestos Heterocíclicos/farmacología , Moraxella/efectos de los fármacos , Moraxella/aislamiento & purificación , Nariz/efectos de los fármacos , Oxitetraciclina/farmacología , Penicilina G Procaína/farmacología , Proteobacteria/efectos de los fármacos , Proteobacteria/aislamiento & purificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Streptococcus/efectos de los fármacos , Streptococcus/aislamiento & purificaciónRESUMEN
Carbon monoxide concentrations in syngas are often high, but tolerance toward CO varies a lot between homoacetogenic bacteria. Analysis of the autotrophic potential revealed that the first isolated acetogenic bacterium Clostridium aceticum was able to use CO as sole carbon and energy source for chemolithoautotrophic carbon fixation but simultaneously showed little tolerance to high CO concentrations. Not yet reported, autotrophic ethanol production by C. aceticum was discovered with CO as a substrate in batch processes. Growth rates estimated in batch processes at varying CO partial pressures were used to identify the CO inhibition kinetics of C. aceticum, using a substrate inhibition model. C. aceticum shows a strong CO inhibition with an optimum CO partial pressure of only 5.4 mbar in the gas phase at cell dry weight concentrations of up to 0.5 g·L -1 . At optimum conditions, growth and acetate formation rates were estimated to be 0.24 hr -1 and 0.52 g·g -1 ·hr -1 , respectively. Syngas fermentation at high partial pressures of up to 280 mbar CO in the inlet gas phase was enabled by applying a continuously operated stirred-tank bioreactor with submerged membranes with total cell retention. Around 70% CO conversion was achieved continuously in the membrane bioreactor with strongly CO inhibited C. aceticum resulting in space-time yields of up to 0.85 g·L -1 ·hr -1 acetate.
Asunto(s)
Monóxido de Carbono/metabolismo , Clostridium/metabolismo , Gasotransmisores/metabolismo , Acetatos/metabolismo , Reactores Biológicos/microbiología , Carbono/metabolismo , Ciclo del Carbono , Monóxido de Carbono/toxicidad , Clostridium/efectos de los fármacos , Clostridium/crecimiento & desarrollo , Etanol/metabolismo , Gasotransmisores/toxicidad , Membranas/microbiologíaRESUMEN
The appendix has been hypothesized to protect the colon against Clostridium difficile infection (CDI) by providing a continuous source of commensal bacteria that crowd out the potentially unhealthy bacteria and/or by contributing to defensive immune dynamics. Here, a series of deterministic systems comprised of ordinary differential equations, which treat the system as an ecological community of microorganisms, model the dynamics of colon microbiome. The first model includes migration of commensal bacteria from the appendix to the gut, while the second model expands this to also include immune dynamics. Simulations and simple analytic techniques are used to explore dynamics under biologically relevant parameters values. Both models exhibited bistability with steady states of a healthy state and of fulminant CDI. However, we find that the appendix size was much too small for migration to affect the stability of the system. Both models affirm the use of fecal transplants in conjunction with antibiotic use for CDI treatment, while the second model also suggests that anti-inflammatory drugs may protect against CDI. Ultimately, in general neither the appendiceal migration rate of commensal microbiota nor the boost to antibody production could exert an appreciable impact on the stability of the system, thus failing to support the proposed protective role of the appendix against CDI.
Asunto(s)
Antibacterianos/administración & dosificación , Infecciones por Clostridium/terapia , Clostridium/efectos de los fármacos , Trasplante de Microbiota Fecal/métodos , Algoritmos , Animales , Apéndice/microbiología , Bacterias/inmunología , Clostridium/fisiología , Infecciones por Clostridium/microbiología , Microbioma Gastrointestinal/inmunología , Microbioma Gastrointestinal/fisiología , Interacciones Huésped-Patógeno/efectos de los fármacos , Humanos , Modelos BiológicosRESUMEN
The narrow-spectrum macrocyclic antibiotic fidaxomicin is approved for treatment of Clostridium difficile infection in many countries and is currently under evaluation in Japan for this indication. This study was conducted to evaluate the effects of fidaxomicin and its major metabolite, OP-1118, on Clostridium spp. isolated in Nagasaki University Hospital, Japan. Isolates were cultured and antimicrobial susceptibility analyses performed according to the Clinical Laboratory Standards Institute methods. Ninety-eight isolates were obtained between 2012 and 2015, 50 of C. difficile and 48 of eight other Clostridium spp. Fidaxomicin had the lowest minimum inhibitory concentration (MIC) of the antimicrobials tested against C. difficile, with MIC90 (MIC range) 0.12 µg/mL (0.015-0.25), versus vancomycin MIC90 0.5 µg/mL (0.5), metronidazole MIC90 0.5 µg/mL (0.12-0.5), and OP-1118 MIC90 4.0 µg/mL (0.5-4.0). Fidaxomicin and OP-1118 each had a similar spectrum of activity against the other Clostridium spp. C. butyricum and the 29 fidaxomicin- and OP-1118-susceptible C. perfringens isolates had the lowest MIC values, and C. bolteae and C. hathewayi higher. All the C. ramosum isolates (n = 6) and one of 30 C. perfringens isolates had low susceptibility to fidaxomicin and OP-1118 (i.e., MIC >64 µg/mL). In summary, this study showed that fidaxomicin was active against a number of Clostridium spp., including C. difficile. Fidaxomicin was generally more effective than its major metabolite OP-1118, but both showed a similar spectrum of activity, suggesting that OP-1118 contributes to the antimicrobial activity of fidaxomicin. These findings were broadly in accordance with those of similar studies conducted in other settings.
Asunto(s)
Aminoglicósidos/farmacología , Antiinfecciosos/farmacología , Clostridium/efectos de los fármacos , Aminoglicósidos/uso terapéutico , Antiinfecciosos/uso terapéutico , Clostridium/clasificación , Clostridium/aislamiento & purificación , Infecciones por Clostridium/tratamiento farmacológico , Fidaxomicina , Humanos , Japón , Pruebas de Sensibilidad MicrobianaRESUMEN
In allogeneic stem cell transplantation (ASCT), systemic broad-spectrum antibiotics are frequently used for treatment of infectious complications, but their effect on microbiota composition is still poorly understood. This retrospective analysis of 621 patients who underwent ASCT at the University Medical Center of Regensburg and Memorial Sloan Kettering Cancer Center in New York assessed the impact of timing of peritransplant antibiotic treatment on intestinal microbiota composition as well as transplant-related mortality (TRM) and overall survival. Early exposure to antibiotics was associated with lower urinary 3-indoxyl sulfate levels (P < .001) and a decrease in fecal abundance of commensal Clostridiales (P = .03) compared with late antibiotic treatment, which was particularly significant (P = .005) for Clostridium cluster XIVa in the Regensburg group. Earlier antibiotic treatment before ASCT was further associated with a higher TRM (34%, 79/236) compared with post-ASCT (21%, 62/297, P = .001) or no antibiotics (7%, 6/88, P < .001). Timing of antibiotic treatment was the dominant independent risk factor for TRM (HR, 2.0; P ≤ .001) in multivariate analysis besides increase age (HR, 2.15; P = .004), reduced Karnofsky performance status (HR, 1.47; P = .03), and female donor-male recipient sex combination (HR, 1.56; P = .02) A competing risk analysis revealed the independent effect of early initiation of antibiotics on graft-versus-host disease-related TRM (P = .004) in contrast to infection-related TRM and relapse (not significant). The poor outcome associated with early administration of antibiotic therapy that is active against commensal organisms, and specifically the possibly protective Clostridiales, calls for the use of Clostridiales-sparing antibiotics and rapid restoration of microbiota diversity after cessation of antibiotic treatment.
Asunto(s)
Antibacterianos/farmacología , Microbioma Gastrointestinal/efectos de los fármacos , Trasplante de Células Madre/métodos , Adulto , Antibacterianos/efectos adversos , Clostridium/efectos de los fármacos , Femenino , Enfermedad Injerto contra Huésped/etiología , Enfermedad Injerto contra Huésped/mortalidad , Humanos , Infecciones/etiología , Infecciones/mortalidad , Masculino , Estudios Retrospectivos , Factores de Riesgo , Trasplante de Células Madre/efectos adversos , Trasplante de Células Madre/mortalidad , Análisis de Supervivencia , Tiempo de Tratamiento , Trasplante Homólogo , Resultado del Tratamiento , Adulto JovenRESUMEN
Clostridiumbolteae, which belongs to the Clostridium clostridioforme complex, is a member of the human gut microbiota. Recent analysis of seven genomes of Cbolteae revealed the presence of an arr-like gene. Among these strains, only 90A7 was found to be resistant to rifampin in the absence of alteration of RpoB. Cloning of arr-cb from 90A7 in Escherichia coli combined with directed mutagenesis demonstrated that Arr-cb was functional but that a Q127âR variant present in 90A9 and 90B3 was inactive. Quantitative reverse transcription-PCR analysis indicated that arr-cb was silent in the four remaining strains because of defective transcription. Thus, two independent mechanisms can make the probably intrinsic arr-cb gene of Cbolteae cryptic.
Asunto(s)
ADP Ribosa Transferasas/genética , Proteínas Bacterianas/genética , Clostridium/efectos de los fármacos , Clostridium/genética , Farmacorresistencia Bacteriana/genética , Rifampin/farmacología , ARN Polimerasas Dirigidas por ADN/genética , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Genoma Bacteriano/genética , Humanos , Pruebas de Sensibilidad Microbiana , Rifampin/químicaRESUMEN
We have developed butanol-producing consolidated bioprocessing from cellulosic substrates through coculture of cellulolytic clostridia and butanol-producing Clostridium saccharoperbutylacetonicum strain N1-4. However, the butanol fermentation by strain N1-4 (which has an optimal growth temperature of 30°C) is sensitive to the higher cultivation temperature of 37°C; the nature of this deleterious effect remains unclear. Comparison of the intracellular metabolites of strain N1-4 cultivated at 30°C and 37°C revealed decreased levels of multiple primary metabolites (notably including nucleic acids and cofactors) during growth at the higher temperature. Supplementation of the culture medium with 250 mg/liter adenine enhanced both cell growth (with the optical density at 600 nm increasing from 4.3 to 10.2) and butanol production (increasing from 3.9 g/liter to 9.6 g/liter) at 37°C, compared to those obtained without adenine supplementation, such that the supplemented 37°C culture exhibited growth and butanol production approaching those observed at 30°C in the absence of adenine supplementation. These improved properties were based on the maintenance of cell viability. We further showed that adenine supplementation enhanced cell viability during growth at 37°C by maintaining ATP levels and inhibiting spore formation. This work represents the first demonstration (to our knowledge) of the importance of adenine-related metabolism for clostridial butanol production, suggesting a new means of enhancing target pathways based on metabolite levels.IMPORTANCE Metabolomic analysis revealed decreased levels of multiple primary metabolites during growth at 37°C, compared to 30°C, in C. saccharoperbutylacetonicum strain N1-4. We found that adenine supplementation restored the cell growth and butanol production of strain N1-4 at 37°C. The effects of adenine supplementation reflected the maintenance of cell viability originating from the maintenance of ATP levels and the inhibition of spore formation. Thus, our metabolomic analysis identified the depleted metabolites that were required to maintain cell viability. Our strategy, which is expected to be applicable to a wide range of organisms, permits the identification of the limiting metabolic pathway, which can serve as a new target for molecular breeding. The other novel finding of this work is that adenine supplementation inhibits clostridial spore formation. The mechanism linking spore formation and metabolomic status in butanol-producing clostridia is expected to be the focus of further research.