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1.
J Dairy Sci ; 103(3): 2111-2116, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31954557

RESUMO

One of the most severe quality defects in hard and semi-hard cheese, the late blowing defect, is caused by endospore-forming bacteria of the genus Clostridium. To minimize financial losses and waste of resources due to cheese spoilage, raw milk with elevated clostridial spore counts should not be used for the production of certain cheese types. In this context, threshold values of clostridial spore concentrations that cause quality defects in cheese are still under debate. To improve our understanding about late blowing defects, further information on the correlation between clostridial spore concentrations in milk and cheese quality is indispensable. Thus, the aim of this study was to monitor the microbiological quality of milk used for Alpine cheese production regarding clostridial endospore levels to facilitate the establishment of threshold spore concentrations that guarantee the absence of quality defects in Austrian cheese. For this purpose, we monitored clostridial endospore levels in vat milk of 4 Alpine dairies throughout the summer grazing period in 2018. Surprisingly, we observed almost complete absence of butyric acid-producing clostridia in milk and no blowing defects in cheese. Hence, critical clostridial spore concentrations could not be verified. Moreover, the observed low spore levels reveal that the prohibition of silage feeding and good farming practices effectively minimize clostridial endospore counts in milk and ensure the manufacture of high-quality cheese even if technological possibilities are limited.


Assuntos
Queijo/microbiologia , Clostridium/isolamento & purificação , Leite/microbiologia , Esporos Bacterianos/isolamento & purificação , Animais , Áustria , Contagem de Colônia Microbiana , Microbiologia de Alimentos
2.
Int. microbiol ; 22(4): 511-520, dic. 2019. graf, tab
Artigo em Inglês | IBECS | ID: ibc-185069

RESUMO

The phylum Firmicutes comprises seven classes where most species are either aerobic or anaerobic endospore former. Inside Firmicutes, species allocated in the genus Bacillus and related genera are collectively named aerobic endospore-forming bacteria (AEFB), and the soil is their major reservoir. AEFB have great importance in health, agriculture, and biotechnology although the more studied species are Bacillus subtilis and the human pathogens Bacillus cereus and Bacillus anthracis. AEFB have great importance in health, agriculture, and biotechnology; although the knowledge about these organisms is based on few species, notably, Bacillus subtilis, Bacillus cereus, and Bacillus anthracis. In this work, we generated partial 16S rRNA gene sequences of both strands of 192 AEFB strains isolated from soils of Distrito Federal, Brazil (SDF strains). The resulting consensus sequences were used to obtain taxonomic assignment and establish the phylogenetic relationships among these strains. Through this approach, we could observe that classified SDF strains were distributed among genera Bacillus (169 strains; 88.02%), Paenibacillus (11; 5.73%), Lysinibacillus (6; 3.13%), Brevibacillus (4; 2.08%), Terribacillus (1; 0.52%), and Rummeliibacillus (1; 0.52%). Phylogenetic trees revealed these 192 SDF strains can be segregated into eight groups spanning families Bacillaceae and Paenibacillaceae belonging to the order Bacillales. To expand the knowledge about the diversity of these SDF strains, further studies regarding characterization with different methodologies are underway


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Assuntos
Poluentes do Solo/análise , Análise do Solo , Esporos Bacterianos/isolamento & purificação , Contagem de Colônia Microbiana , RNA Ribossômico 16S/genética , Bactérias Anaeróbias/isolamento & purificação , Bacillales/isolamento & purificação , Esporos Fúngicos/genética , Brasil , Bacillales/genética , Perfilação da Expressão Gênica/métodos
3.
Biosci Biotechnol Biochem ; 83(12): 2327-2333, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31403387

RESUMO

This study was aimed to investigate the presence of Bacillus coagulans vegetative cells in the intestine and fecal samples in rats fed B. coagulans spores as well as to estimate the ratios of spores and vegetative cells in these samples. A two-step process has been developed to enumerate B. coagulans in different mixed bacterial samples, specifically (1) observation of yellow ring formation on modified GYEA medium upon incubation at 55°C, (2) microscopic examination of spore formation after 7 d of incubation. Our results have demonstrated the presence of vegetative cells in the intestinal and fecal samples in rats fed B. coagulans spores. The ratios of B. coagulans spores and vegetative cells in cecal fluid, colonic content, and feces were approximately 2:8, 2:8, and 4:6, respectively. The existence of B. coagulans vegetative cells improved the intestinal milieu through an elevated short-chain fatty acid concentrations, higher fecal moisture, and lower fecal pH.


Assuntos
Bacillus coagulans/fisiologia , Fezes/microbiologia , Intestinos/microbiologia , Esporos Bacterianos/isolamento & purificação , Animais , Ácidos Graxos/metabolismo , Concentração de Íons de Hidrogênio , Intestinos/citologia , Masculino , Probióticos , Ratos , Ratos Sprague-Dawley
4.
Indian J Med Microbiol ; 37(1): 116-119, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31424022

RESUMO

Aims and Objectives: Molecular confirmation of the circulating Bacillus anthracis during outbreak of anthrax in different villages of Simdega district, Jharkhand, India. Materials and Methods: Blood samples with swabs from skin lesions (eschar) were collected from the suspected cases of Anthrax from October 2014 to June 2016 from Simdega district, Jharkhand. All the swabs were inoculated on polymyxin lysozyme EDTA thallous acetate media, nutrient agar media as well as 5% sheep blood agar media. Gamma-phage lysis was done. DNA extraction was done using a QIAamp DNA Mini Kit (QIAGEN, Valencia, CA, USA) and subjected to polymerase chain reaction (PCR) using anthrax-specific primers. Results: On Gram and acid fast staining, purple rods and pink-coloured anthrax spores were detected. Capsular and M'Fadyean staining was done. Gamma-phage lysed B. anthracis culture. Of 39 suspected cases, 8 were culture and PCR positive and showed gamma-phage lysis. 3 deaths were reported. Discussion and Conclusion: The conventional and real-time PCR methods are suitable for both the clinical and the epidemiological practice.


Assuntos
Antraz/diagnóstico , Antraz/epidemiologia , Bacillus anthracis/genética , Dermatopatias Bacterianas/diagnóstico , Dermatopatias Bacterianas/epidemiologia , Esporos Bacterianos/isolamento & purificação , Adulto , Antraz/tratamento farmacológico , Antibacterianos/uso terapêutico , Bacillus anthracis/isolamento & purificação , Ciprofloxacino/uso terapêutico , Surtos de Doenças , Humanos , Índia/epidemiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Dermatopatias Bacterianas/tratamento farmacológico , Adulto Jovem
5.
J Dairy Sci ; 102(9): 8273-8289, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31326179

RESUMO

The occurrence of Paenibacillus and Clostridium spores in silage is of great concern for dairy producers because their spores can contaminate milk and damage processed milk and semi-hard cheeses. Spoiled silage is considered to be the main contamination source of the total mixed ration (TMR), feces of dairy cows, and consequently bulk tank milk via the contamination of cow teats by dirt during milking. The presence of an anaerobic and facultative anaerobic sporeformer population in different matrices (soil, corn silage, other feeds, TMR, feces, and milk) and its transmission pathway has been studied on 49 dairy farms by coupling plate count data with 16S-DNA identification. The different matrices have shown a high variability in the anaerobic and facultative anaerobic spore count, with the highest values being found in the aerobically deteriorated areas of corn silages. Clostridium tyrobutyricum, Paenibacillus macerans, and Paenibacillus thermophilus were detected in all the matrices. The TMR spore count was influenced by the amount of spoiled corn silage in the TMR and by the care taken when cleaning the spoiled silage before feed-out. Most of the farms that prevent the presence of visible moldy silage in the silo and carefully clean to remove molded spots were able to maintain their TMR spore counts below 4.0 log spores/g. When a level of 4.5 log spores/g of TMR was exceeded, the feces presented a greater contamination than 3.0 log spores/g. Moreover, the higher the number of spores in the feces was, the higher the number of spores in the milk. Most of the farms that presented a feces contamination greater than 5.0 log spores/g had a higher milk spore contamination than 1,000 spores/L. Careful animal cleaning and good milking practices have been found to be essential to maintain low levels of contamination in bulk tank milk, but it has emerged that only by coupling these practices with a correct silage management and cleaning during TMR preparation can the contamination of milk by spores be kept at a low level. It has been found that aerobically deteriorated silage has a great capacity to contaminate TMR and consequently to increase the risk of milk spore contamination, even when routine milking practices are adopted correctly.


Assuntos
Ração Animal/microbiologia , Clostridium/isolamento & purificação , Indústria de Laticínios/métodos , Leite/microbiologia , Paenibacillus/isolamento & purificação , Esporos Bacterianos/isolamento & purificação , Criação de Animais Domésticos/métodos , Animais , Bovinos , Clostridium tyrobutyricum/isolamento & purificação , Contagem de Colônia Microbiana/veterinária , Fazendas , Fezes/microbiologia , Feminino , Microbiologia de Alimentos/métodos , Higiene , Glândulas Mamárias Animais , Fatores de Risco , Silagem
6.
PLoS One ; 14(7): e0219892, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31356641

RESUMO

The Gram-positive bacterium Bacillus subtilis is able to form endospores which have a variety of biotechnological applications. Due to this ability, B. subtilis is as well a model organism for cellular differentiation processes. Sporulating cultures of B. subtilis form sub-populations which include vegetative cells, sporulating cells and spores. In order to readily and rapidly quantify spore formation we employed flow cytometric and fluorescence activated cell sorting techniques in combination with nucleic acid fluorescent staining in order to investigate the distribution of sporulating cultures on a single cell level. Automated gating procedures using Gaussian mixture modeling (GMM) were employed to avoid subjective gating and allow for the simultaneous measurement of controls. We utilized the presented method for monitoring sporulation over time in germination deficient strains harboring different genome modifications. A decrease in the sporulation efficiency of strain Bs02018, utilized for the display of sfGFP on the spores surface was observed. On the contrary, a double knock-out mutant of the phosphatase gene encoding Spo0E and of the spore killing factor SkfA (Bs02025) exhibited the highest sporulation efficiency, as within 24 h of cultivation in sporulation medium, cultures of BS02025 already consisted of 80% spores as opposed to 18% for the control strain. We confirmed the identity of the different subpopulations formed during sporulation by employing sorting and microscopy.


Assuntos
Bacillus subtilis/fisiologia , Proteínas de Bactérias/genética , Esporos Bacterianos/isolamento & purificação , Bacillus subtilis/genética , Proteínas de Bactérias/química , Técnicas Bacteriológicas , Citometria de Fluxo , Corantes Fluorescentes/química , Regulação Bacteriana da Expressão Gênica , Técnicas de Inativação de Genes , Distribuição Normal , Esporos Bacterianos/genética
7.
Talanta ; 204: 44-49, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31357318

RESUMO

Bacillus cereus, a common soil bacterium, has been shown to act as a biogeochemical indicator for concealed mineralisations, e.g., vein-type Au deposits. Field and cultivation-free detection of Bacillus cereus in the presence of Au3+ and other metal ions is significantly important but still almost blank in current biogeochemical prospecting of gold mine system. Herein, a self-established simple approach was slightly improved to make silver nanoparticles (Ag NPs) rapidly concentrated on every bacterial cell, and highly strong and distinct surface-enhanced Raman scattering (SERS) signals of Bacillus cereus free from any native fluorescence have been obtained in a so called 'mixing-and-measuring' manner. Furthermore, SERS was used for the first time to our knowledge to investigate the impacts of different concentrations of metal ions on Bacillus cereus, and successfully utilized for distinguishing Au3+ ions from other species. A more convincing multi-Raman criterion based on Raman bands, and further the entire Raman spectrum in combination with statistical analysis (e.g., principal component analysis (PCA)) were found capable of detecting spectral differences of Bacillus cereus in the presence of metal ions (Au3+, Ag+, Cu2+ and Zn2+) with different concentrations. An interesting phenomenon has been found that except for Au3+ ions, the highest permissive concentration of other metal ions for the detected Bacillus cereus is up to 10 µg/mL possibly due to their resistance to Au. The results also indicate that an effective biogeochemical exploration technique of SERS spectral response may be developed, where Bacillus cereus spore counts are measured in the field and used as a pre-screening method to target areas useful for further sampling and complete geochemical analysis.


Assuntos
Bacillus cereus/isolamento & purificação , Carga Bacteriana/métodos , Ouro/farmacologia , Bacillus cereus/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ouro/química , Ouro/toxicidade , Nanopartículas Metálicas/química , Mineração/métodos , Análise de Componente Principal , Prata/química , Análise Espectral Raman/métodos , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/isolamento & purificação
8.
Forensic Sci Int ; 301: e55-e58, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31153677

RESUMO

Efficient and safe detection of Bacillus anthracis spores (BAS) is a challenging task especially in bio-terror scenarios where the agent is concealed. We provide a proof-of-concept for the identification of concealed BAS inside mail envelopes using short-wave infrared hyperspectral imaging (SWIR-HSI). The spores and two other benign materials are identified according to their typical absorption spectrum. The identification process is based on the removal of the envelope signal using a new automatic new algorithm. This method may serve as a fast screening tool prior to using classical bioanalytical techniques.


Assuntos
Bacillus anthracis/isolamento & purificação , Raios Infravermelhos , Análise Espectral/métodos , Esporos Bacterianos/isolamento & purificação , Algoritmos , Bioterrorismo , Ciências Forenses/métodos , Humanos , Serviços Postais
9.
Mycorrhiza ; 29(4): 341-349, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31190279

RESUMO

The extraradical mycelium (ERM) produced by arbuscular mycorrhizal fungi is fundamental for the maintenance of biological fertility in agricultural soils, representing an important inoculum source, together with spores and mycorrhizal root fragments. Its viability and structural traits, such as density, extent and interconnectedness, which are positively correlated with the growth and nutrition of host plants, may be affected by different agronomic practices, including the use of pesticides and by different mycorrhizospheric communities. This work, carried out using a whole-plant experimental model system, showed that structural traits of ERM, such as length and density, were strongly decreased by the herbicides dicamba and glufosinolate and the fungicides benomyl and fenhexamid, while anastomosis frequency and hyphal branching were differentially modulated by singly inoculated mycorrhizospheric bacteria, depending on their identity.


Assuntos
Fenômenos Fisiológicos Bacterianos , Chicória/microbiologia , Fungicidas Industriais/farmacologia , Glomeromycota/efeitos dos fármacos , Glomeromycota/crescimento & desenvolvimento , Herbicidas/farmacologia , Micélio/crescimento & desenvolvimento , Micorrizas/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Benomilo/farmacologia , Chicória/crescimento & desenvolvimento , Dicamba/farmacologia , Hifas/efeitos dos fármacos , Hifas/crescimento & desenvolvimento , Micélio/efeitos dos fármacos , Micorrizas/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Esporos Bacterianos/genética , Esporos Bacterianos/isolamento & purificação , Esporos Bacterianos/fisiologia
10.
J Dairy Sci ; 102(8): 6885-6900, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31202649

RESUMO

Mesophilic and thermophilic spore-forming bacteria represent a challenge to the dairy industry, as these bacteria are capable of surviving adverse conditions associated with processing and sanitation and eventually spoil dairy products. The dairy farm environment, including soil, manure, silage, and bedding, has been implicated as a source for spores in raw milk. High levels of spores have previously been isolated from bedding, and different bedding materials have been associated with spore levels in bulk tank (BT) raw milk; however, the effect of different bedding types, bedding management practices, and bedding spore levels on the variance of spore levels in BT raw milk has not been investigated. To this end, farm and bedding management surveys were administered and unused bedding, used bedding, and BT raw milk samples were collected from dairy farms (1 or 2 times per farm) across the United States over 1 yr; the final data set included 182 dairy farms in 18 states. Bedding suspensions and BT raw milk were spore pasteurized (80°C for 12 min), and mesophilic and thermophilic spores were enumerated. Piecewise structural equation modeling analysis was used to determine direct and indirect pathways of association among farm and bedding practices, levels of spores in unused and used bedding, and levels of spores in BT raw milk. Separate models were constructed for mesophilic and thermophilic spore levels. The analyses showed that bedding material had a direct influence on levels of spores in unused and used bedding as well as an indirect association with spore levels in BT raw milk through used bedding spore levels. Specific bedding and farm management practices as well as cow hygiene in the housing area were associated with mesophilic and thermophilic spore levels in unused bedding, used bedding, and BT raw milk. Notably, levels of spores in used bedding were positively related to those in unused bedding, and used bedding spore levels were positively related to those in BT raw milk. The results of this study increase the understanding of the levels and ecology of mesophilic and thermophilic spores in raw milk, emphasize the possible role of bedding as a source of spores on-farm, and present opportunities for dairy producers to reduce spore levels in BT raw milk.


Assuntos
Indústria de Laticínios/métodos , Abrigo para Animais , Leite/microbiologia , Esporos Bacterianos/isolamento & purificação , Animais , Roupas de Cama, Mesa e Banho/microbiologia , Bovinos , Contagem de Colônia Microbiana , Fazendas , Feminino , Pasteurização , Silagem/microbiologia , Estados Unidos
11.
Int Microbiol ; 22(4): 511-520, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31049768

RESUMO

The phylum Firmicutes comprises seven classes where most species are either aerobic or anaerobic endospore former. Inside Firmicutes, species allocated in the genus Bacillus and related genera are collectively named aerobic endospore-forming bacteria (AEFB), and the soil is their major reservoir. AEFB have great importance in health, agriculture, and biotechnology although the more studied species are Bacillus subtilis and the human pathogens Bacillus cereus and Bacillus anthracis. AEFB have great importance in health, agriculture, and biotechnology; although the knowledge about these organisms is based on few species, notably, Bacillus subtilis, Bacillus cereus, and Bacillus anthracis. In this work, we generated partial 16S rRNA gene sequences of both strands of 192 AEFB strains isolated from soils of Distrito Federal, Brazil (SDF strains). The resulting consensus sequences were used to obtain taxonomic assignment and establish the phylogenetic relationships among these strains. Through this approach, we could observe that classified SDF strains were distributed among genera Bacillus (169 strains; 88.02%), Paenibacillus (11; 5.73%), Lysinibacillus (6; 3.13%), Brevibacillus (4; 2.08%), Terribacillus (1; 0.52%), and Rummeliibacillus (1; 0.52%). Phylogenetic trees revealed these 192 SDF strains can be segregated into eight groups spanning families Bacillaceae and Paenibacillaceae belonging to the order Bacillales. To expand the knowledge about the diversity of these SDF strains, further studies regarding characterization with different methodologies are underway.


Assuntos
Bacillales/classificação , Bacillales/isolamento & purificação , Filogenia , Microbiologia do Solo , Bacillales/genética , Brasil , DNA Bacteriano/genética , Variação Genética , RNA Ribossômico 16S/genética , Esporos Bacterianos/classificação , Esporos Bacterianos/genética , Esporos Bacterianos/isolamento & purificação
12.
J Appl Microbiol ; 126(6): 1700-1707, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30776160

RESUMO

AIMS: To develop a gel formulation to trigger a visual signal for rapid disclosure of the location and extent of surface contamination with viable Bacillus anthracis spores. METHODS AND RESULTS: Methylumbelliferyl-α-d-glucopyranoside was combined with hyaluronic acid to produce a gel that could be applied to a surface as a coating. It remained hydrated for a sufficient time for α-glucosidase activity present in intact B. anthracis spores to cleave the substrate and release the fluorescent product, methylumbelliferone. The presence of B. anthracis spores could be disclosed at 5 × 104 CFU per reaction test well (0·32 cm2 ) both visually and using fluorescence detection equipment. CONCLUSIONS: The disclosure gel provides a rapid, visual response to the presence of B. anthracis spores on a surface. SIGNIFICANCE AND IMPACT OF THE STUDY: The disclosure gel demonstrates the first steps towards the development of a formulation that can provide nonspecialist users with a visual alert to the presence of B. anthracis spores on a surface. It is envisioned that such a formulation would be beneficial in scenarios where exposure to spore release is a risk, and could be used in the initial assessment of equipment to aid prioritization and localized execution of a decontamination strategy.


Assuntos
Bacillus anthracis/isolamento & purificação , Descontaminação/métodos , Exposição Ambiental/prevenção & controle , Técnicas Microbiológicas/métodos , Esporos Bacterianos/isolamento & purificação , Bacillus anthracis/enzimologia , Bacillus anthracis/metabolismo , Ácido Hialurônico/química , Himecromona/química , Himecromona/metabolismo , Indicadores e Reagentes , Esporos Bacterianos/enzimologia , Esporos Bacterianos/metabolismo , alfa-Glucosidases/metabolismo
13.
Am J Infect Control ; 47(7): 780-785, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30723028

RESUMO

BACKGROUND: Clostridium difficile infection (CDI) is a leading cause of hospital-associated infections. Antibiotic stewardship, environmental disinfection, and reduction of transmission via health care workers are the major modes of CDI prevention within hospitals. METHODS: The aim of this study was to evaluate the role of the environment in the spread of CDI within hospital rooms. Bed tracing of positive-CDI inpatients was performed to detect the strength of association to specific rooms. Environmental cultures were conducted to identify adequacy of environmental C difficile (CD) spores. Whole-genome sequencing was performed to evaluate the degree of CD relatedness. RESULTS: Bed tracing performed for 211 CDI patients showed a limited list of high-burden rooms. Environmental cultures for surfaces disinfected with a sporicidal agent were almost entirely negative, whereas the floors were positive for CDI in 15% of the studied patient rooms. Whole-genome sequencing did not detect any close genetic relatedness. CONCLUSIONS: Unlike in an outbreak setting, bed tracing did not yield conclusive results of room reservoirs. The C diff Banana Broth culture was inexpensive, sensitive, and easy to incubate under aerobic conditions. Sporicidal disinfectants were effective in eliminating CD from the environment. CD spores were found on floors and hard-to-clean surfaces.


Assuntos
Gestão de Antimicrobianos/métodos , Infecções por Clostridium/epidemiologia , Clostridium difficile/isolamento & purificação , Infecção Hospitalar/epidemiologia , Reservatórios de Doenças/microbiologia , Idoso , Técnicas de Tipagem Bacteriana , Infecções por Clostridium/etnologia , Infecções por Clostridium/microbiologia , Clostridium difficile/classificação , Clostridium difficile/efeitos dos fármacos , Clostridium difficile/genética , Infecções Comunitárias Adquiridas , Busca de Comunicante/estatística & dados numéricos , Infecção Hospitalar/etnologia , Infecção Hospitalar/microbiologia , Desinfetantes/farmacologia , Feminino , Genoma Bacteriano , Hospitais , Humanos , Masculino , Pessoa de Meia-Idade , Quartos de Pacientes , Pennsylvania/epidemiologia , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/isolamento & purificação , Sequenciamento Completo do Genoma
14.
Int J Food Microbiol ; 291: 173-180, 2019 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-30508773

RESUMO

The heat resistance of the bacterial spores of Moorella thermoacetica, Clostridium sporogenes, Geobacillus stearothermophilus and Bacillus coagulans was determined over a wide range of temperatures using the capillary method and thermoresistometer Mastia. The results showed that the two experimental methods gave similar heat resistance values excepted for Geobacillus stearothermophilus. The effect of temperature on thermal resistance was evaluated using the Arrhenius and Bigelow models. The fit of the heat sensitivity parameters of the Arrhenius and Bigelow models on the heat resistance parameter values obtained over a wide temperature range was equally good. Despite the apparent mathematical incompatibility of the two equations, it is recognized that they yield the same goodness of fit. This paper finds a mathematical reason for this convergence and explains why inside a temperature range of at least 100 °C, no significant difference in the quality of fit between these two models can be found.


Assuntos
Contaminação de Alimentos , Microbiologia de Alimentos , Temperatura Alta , Modelos Teóricos , Bacillus coagulans/isolamento & purificação , Clostridium/isolamento & purificação , Alimentos em Conserva/microbiologia , Geobacillus stearothermophilus/isolamento & purificação , Esporos Bacterianos/isolamento & purificação
15.
Int J Food Microbiol ; 291: 144-150, 2019 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-30500691

RESUMO

Clostridium perfringens type F is a spore-forming anaerobe that causes bacterial food-borne illness in humans. The disease develops when ingested vegetative cells reach the intestinal tract and begin to form spores that produce the diarrheagenic C. perfringens enterotoxin (CPE). Given that CPE production is regulated by the master regulator of sporulation (transcription factor Spo0A), the identification of sporulation-inducing factors in the intestine is relevant to better understanding of the disease. To examine these factors, we established assays to quantify C. perfringens sporulation stage under microscopy by using two fluorescent reporters, namely, Evoglow-Bs2 and CpEGFP. When the reporter genes were placed under control of the cpe promoter, both protein products were expressed specifically during sporulation. However, the intensity of the anaerobic reporter Evoglow-Bs2 was weak and rapidly photobleached during microscopic observation. Alternatively, CpEGFP, a canonical green fluorescence protein with optimized codon usage for Clostridium species, was readily detectable in the mother-cell compartment of most bacteria at early stages of sporulation. Additionally, CpEGFP expression predicted final spore yield and was quantifiable in 96-well plates using fluorescence plate reader. These results indicate that CpEGFP can be used to analyze the sporulation of C. perfringens and has a potential application in the large-scale screening of sporulation-regulating biomolecules.


Assuntos
Clostridium perfringens/isolamento & purificação , Genes Reporter , Proteínas de Fluorescência Verde/genética , Esporos Bacterianos/isolamento & purificação , DNA Bacteriano/isolamento & purificação , Enterotoxinas/isolamento & purificação , Contaminação de Alimentos/análise , Microbiologia de Alimentos , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Proteínas de Fluorescência Verde/metabolismo , Plasmídeos/genética , Regiões Promotoras Genéticas
16.
Biosens Bioelectron ; 126: 640-646, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30522085

RESUMO

Herein, we report an impedimetric DNA-based aptamer sensor for a single-step detection of B. anthracis spore simulant (B. cereus spore). Specifically, we designed a miniaturized label-free aptasensor for B. cereus spores based on a gold screen-printed electrode functionalized with B. cereus spores-binding aptamer (BAS-6R). Several parameters were optimized to fabricate the aptasensor such as the concentration of DNA aptamer solution (0.5 µM), the time (48 h), the temperature (4 °C), and the pH (7.5) for aptamer immobilization on the working electrode surface. Once the aptasensor was developed, it was tested against B. cereus spores 14579 evaluating the effect of incubation time and MgCl2 concentration. Under the optimized conditions (incubation time equal to 3 h and absence of MgCl2), B. cereus spores 14579 were detected with a linear range between 104 CFU/ml and 5 × 106 CFU/ml and a detection limit of 3 × 103 CFU/ml. Furthermore, the study of selectivity toward B. cereus 11778, B. subtilis, Legionella pneumophila, and Salmonella Typhimurium has demonstrated the capability of this sensor to detect B. cereus spores, proving the suitability of the DNA-based sensing element combined with a portable instrument for a label-free measurement on site of B. anthracis spore simulant.


Assuntos
Aptâmeros de Nucleotídeos/química , Bacillus anthracis/isolamento & purificação , Técnicas Biossensoriais , Esporos Bacterianos/isolamento & purificação , Bacillus anthracis/patogenicidade , Técnicas Eletroquímicas , Ouro/química , Humanos , Esporos Bacterianos/patogenicidade
17.
Environ Microbiol Rep ; 11(3): 352-360, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30043505

RESUMO

Bacterial endospores are highly abundant in marine sediments, but their taxonomic identity and ecology is largely unknown. We selectively extracted DNA from endospores and vegetative cells and sequenced 16S rRNA genes to characterize the composition of the endospore and vegetative Firmicutes communities in the sediment and water column of Aarhus Bay (Denmark). The endospore community in the sediment was dominated by the families Bacillaceae, Lachnospiraceae, Clostridiaceae and Ruminoccocaceae. These families were also represented in the vegetative community in the sediment and the endospore community in the water column. OTUs of high relative abundance in the endospore community were also represented in the vegetative Firmicutes community. Other OTUs were exclusively found in the endospore communities. This suggests that endospores accumulate in marine sediments due to passive deposition from the water column and sporulation of vegetative cells in the sediment. Some OTUs were detected in the endospore community of the water column and the vegetative community the sediment indicating that endospores deposited from the water column may germinate upon burial/deposition in the sediment. We provide novel insight into the composition of endospore communities in marine sediments and highlight their role in microbial dispersal and as a seed bank in subsurface sediments.


Assuntos
Firmicutes/isolamento & purificação , Sedimentos Geológicos/microbiologia , Microbiota , Baías/microbiologia , DNA Bacteriano/genética , Dinamarca , Firmicutes/classificação , Firmicutes/genética , RNA Ribossômico 16S , Análise de Sequência de DNA , Esporos Bacterianos/classificação , Esporos Bacterianos/genética , Esporos Bacterianos/isolamento & purificação
18.
J Microbiol Methods ; 156: 5-8, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30452937

RESUMO

Environmental sampling is a critical component of the post decontamination verification process following a bioterrorism event. The current work was performed to produce a less labor-intensive method for processing cellulose sponge-wipes used for sampling areas potentially contaminated with low concentrations (i.e., post-decontamination) of Bacillus anthracis spores. An alternative fast-analysis processing method was compared to the processing protocol validated by the Centers for Disease Control and Prevention (CDC) for the Laboratory Response Network (LRN). Glazed tile coupons (1102 cm2) were inoculated with 50, 500, or 5000 spores of Bacillus thuringiensis subsp. kurstaki (Btk), then sampled with cellulose sponges. Sampling was limited to a 25- by 25-cm area and performed in the same manner as the CDC sampling method. Samples were then processed using either the alternative "Fast Analysis" method or the "CDC method". Three different analysts repeated the tests at each concentration utilizing each method. Mean recoveries, labor time, and potentially hazardous waste produced were compared for the two methods. The mean percent recoveries and standard errors for the samples processed using the "CDC method" were 39.9 ±â€¯6.7, 43 ±â€¯7.6, and 36.8 ±â€¯10.1 for the 5000, 500, and 50 spore loading levels, respectively; compared to 54.2 ±â€¯12.9, 64.2 ±â€¯21.7, and 45.2 ±â€¯8.6 for the "Fast Analysis" method. At each titer tested the "Fast Analysis" method resulted in a statistically significant higher percent recovery. Furthermore, analysts processed samples utilizing the "Fast Analysis" method in less than half the time and generated half as much potentially hazardous waste compared to the "CDC method".


Assuntos
Bacillus thuringiensis/isolamento & purificação , Armas Biológicas , Descontaminação/métodos , Manejo de Espécimes/métodos , Esporos Bacterianos/isolamento & purificação , Técnicas Bacteriológicas
19.
Am J Infect Control ; 47(4): 459-461, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30471969

RESUMO

In a hospital and affiliated long-term care facility, we found that shared wheelchairs were frequently contaminatedwith healthcare-associated pathogens, including Clostridium difficile spores. A network graph of 851 wheelchair transports over 3days demonstrated frequent movement between inpatient wards andoutpatient clinics, radiology, and physical therapy. These results highlight the potential for shared wheelchairs to serve as a vector for pathogen transmission.


Assuntos
Clostridium difficile/isolamento & purificação , Fômites/microbiologia , Instalações de Saúde , Esporos Bacterianos/isolamento & purificação , Cadeiras de Rodas/microbiologia , Infecções por Clostridium/transmissão , Infecção Hospitalar/transmissão , Transmissão de Doença Infecciosa , Humanos
20.
J Appl Microbiol ; 126(2): 348-358, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30106202

RESUMO

The purpose of this article is to highlight some areas of research with spores of bacteria of Firmicute species in which the methodology too commonly used is not optimal and generates misleading results. As a consequence, conclusions drawn from data obtained are often flawed or not appropriate. Topics covered in the article include the following: (i) the importance of using well-purified bacterial spores in studies on spore resistance, composition, killing, disinfection and germination; (ii) methods for obtaining good purification of spores of various species; (iii) appropriate experimental approaches to determine mechanisms of spore resistance and spore killing by a variety of agents, as well as known mechanisms of spore resistance and killing; (iv) common errors made in drawing conclusions about spore killing by various agents, including failure to neutralize chemical agents before plating for viable spore enumeration, and equating correlations between changes in spore properties accompanying spore killing with causation. It is hoped that a consideration of these topics will improve the quality of spore research going forward.


Assuntos
Bacillales/efeitos dos fármacos , Clostridiales/efeitos dos fármacos , Esporos Bacterianos/efeitos dos fármacos , Farmacorresistência Bacteriana , Esporos Bacterianos/isolamento & purificação
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