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1.
Int J Food Microbiol ; 355: 109331, 2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34364061

RESUMO

Penicillium spp. is considered a major spoilage fungus of cheeses. The use of lactic acid bacteria (LAB) with antifungal activity is an interesting possibility of biopreservation. In this study, the isolation and characterization of anti-Penicillium LAB from milk was carried out. Ninety-three milk samples were analysed and a total of 57 strains of LAB active against P. nordicum were isolated, mainly from goat and cow milk. Thirty-four isolates with strong activity were selected and identified, Lacticaseibacillus casei (11), L. paracasei (9) and L. rhamnosus (5) being the dominant species. The antifungal spectrum of these 34 LAB against strains of P. commune and P. verrucosum was investigated. L. casei, L. paracasei and L. rhamnosus were the most active and P. nordicum was the most susceptible fungus. Two isolates (L. casei Lc-51/3 and L. paracasei Lp-25/1) with high antifungal activity showed a moderate to high reduction on the growth of Penicillium nordicum and, in a lesser extent, of P. commune, and also a reducing effect on the ochratoxin A and cyclopiazonic acid production. In addition, these isolates demonstrated activity against several food pahogens. These findings indicate their suitability for the development of protective adjunct starters against spoilage and toxigenic microorganisms in cheese processing.


Assuntos
Microbiologia de Alimentos , Lactobacillales , Interações Microbianas , Penicillium , Animais , Antifúngicos/farmacologia , Queijo/microbiologia , Lactobacillales/fisiologia , Interações Microbianas/fisiologia , Leite/microbiologia , Penicillium/fisiologia
2.
J Dairy Res ; 88(3): 302-306, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34372963

RESUMO

In this Research Communication we evaluate the use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify 380 bacteria isolated from cases of bovine mastitis in Brazil. MALDI-TOF MS identifications were compared to previous identifications by biochemical tests and 16S rRNA sequencing. MALDI-TOF MS achieved a typeability of 95.5%. The accuracy of MALDI-TOF MS for the identification of Staphylococcus isolates was 93.2%. The agreement between MALDI-TOF MS and biochemical identification of Streptococcus agalactiae was 96%, however, the agreement between these techniques for identifying other catalase-negative, Gram-positive cocci was lower. Agreement in identifying Gram-negative bacteria at the genus level was 90.5%. Our findings corroborate that MALDI-TOF MS is an accurate, rapid and simple technique for identifying bovine mastitis pathogens. The availability of this methodology in some research institutions would represent a significant step toward increasing the diagnosis and epidemiological studies of bovine mastitis and other animal infectious diseases in Brazil.


Assuntos
Mastite Bovina/microbiologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/veterinária , Animais , Brasil , Bovinos , Feminino , Bactérias Gram-Negativas/classificação , Bactérias Gram-Negativas/genética , Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/genética , Leite/microbiologia , RNA Ribossômico 16S/genética , Sensibilidade e Especificidade , Análise de Sequência de RNA , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Staphylococcus/genética , Streptococcus agalactiae/genética
3.
J Dairy Res ; 88(3): 307-313, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34392841

RESUMO

Dairy goat farming is an important sector of the agricultural industry in Greece, with an annual total milk production exceeding 450 000 l and accounting for over 25% of all goat milk produced in the European Union; this milk is used mainly for cheese production. Despite the importance of goat milk for the agricultural sector in Greece, no systematic countrywide investigations in the bulk-tank milk of goats in Greece have been reported. Objectives were to investigate somatic cell counts (SCC) and total bacterial counts (TBC) in raw bulk-tank milk of goat herds in Greece, study factors influencing SCC and TBC therein and evaluate their possible associations with milk content. Throughout Greece, 119 dairy goat herds were visited for milk sampling for somatic cell counting, microbiological examination and composition measurement. Geometric mean SCC and TBC were 0.838 × 106 cells ml-1 and 581 × 103 cfu ml-1, respectively. Multivariable analyses revealed annual frequency of check-ups of milking system and total milk quantity per goat (among 53 variables) to be significant for increased SCC; no factor emerged (among 58 variables) to be significant for increased TBC. Negative correlation of SCC with total protein was found; mean total protein content in the bulk-tank milk in herds with SCC >0.75 × 106 cells ml-1 was 5.1% lower and in herds with SCC >1.5 × 106 cells ml-1, it was 7.8% lower.


Assuntos
Carga Bacteriana/veterinária , Contagem de Células/veterinária , Cabras , Leite/citologia , Leite/microbiologia , Animais , Composição Corporal , Indústria de Laticínios/métodos , Feminino , Grécia , Leite/química , Proteínas do Leite/análise , Staphylococcus/isolamento & purificação
4.
J Dairy Res ; 88(3): 314-320, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34412714

RESUMO

Subclinical mastitis (SCM) in water buffalo is a production disease associated with decreased milk yield and impaired milk quality and safety. Water buffalo is an important livestock species in Bangladesh, but information about the occurrence and aetiology of SCM in this species is scarce. A cross-sectional study was conducted as part of the Udder Health Bangladesh Programme to (i) determine the occurrence of SCM and bulk milk somatic cell count (SCC) in water buffalo in Bangladesh, (ii) identify pathogens causing SCM and (iii) evaluate penicillin resistance in isolated staphylococci strains. Sixteen buffalo farms in the Bagerhat and Noakhali regions of Bangladesh were selected for study and a bulk milk sample was collected from each farm. In addition, 299 udder quarter milk samples were collected from 76 animals. The bulk milk samples were assessed by direct SCC and the quarter milk samples by California mastitis test (CMT). The occurrence of SCM calculated at quarter and animal level was 42.5 and 81.6%, respectively. Milk samples from 108 CMT-positive quarters in 48 animals and 38 randomly selected CMT-negative quarters in 24 animals were investigated using bacteriological culture. Estimated mean bulk milk SCC was 195 000 cells/ml milk (range 47 000- 587 000 cells/ml milk). On culture, estimated quarter-level intramammary infection (IMI) was 40.4%. The identity of isolated bacteria was confirmed by MALDI-TOF mass spectrometry. Non-aureus staphylococci (NAS) were the most common pathogens (24.7%) and, among 36 NAS tested, 36.1% were resistant to penicillin. Thus there was high occurrence of SCM on the study farms, with relatively high penicillin resistance in NAS. Further studies are needed to identify underlying risk factors and develop an udder health control strategy for water buffalo in Bangladesh.


Assuntos
Búfalos , Mastite/veterinária , Animais , Infecções Bacterianas/microbiologia , Infecções Bacterianas/veterinária , Bangladesh/epidemiologia , Contagem de Células/veterinária , Estudos Transversais , Indústria de Laticínios/métodos , Fazendas/estatística & dados numéricos , Feminino , Mastite/epidemiologia , Mastite/etiologia , Leite/citologia , Leite/microbiologia , Resistência às Penicilinas , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/veterinária , Staphylococcus/efeitos dos fármacos , Staphylococcus/isolamento & purificação
5.
Molecules ; 26(16)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34443691

RESUMO

BACKGROUND: Milk is considered an important source of bioactive peptides, which can be produced by endogenous or starter bacteria, such as lactic acid bacteria, that are considered effective and safe producers of food-grade bioactive peptides. Among the various types of milk, donkey milk has been gaining more and more attention for its nutraceutical properties. METHODS: Lactobacillus rhamnosus 17D10 and Lactococcus lactis subsp. cremoris 40FEL3 were selected for their ability to produce peptides from donkey milk. The endogenous peptides and those obtained after bacterial fermentation were assayed for their antioxidant, antibacterial, and antiviral activities. The peptide mixtures were characterized by means of LC-MS/MS and then analyzed in silico using the Milk Bioactive Peptide DataBase. RESULTS: The peptides produced by the two selected bacteria enhanced the antioxidant activity and reduced E. coli growth. Only the peptides produced by L. rhamnosus 17D10 were able to reduce S. aureus growth. All the peptide mixtures were able to inhibit the replication of HSV-1 by more than 50%. Seventeen peptides were found to have 60% sequence similarity with already known bioactive peptides. CONCLUSIONS: A lactic acid bacterium fermentation process is able to enhance the value of donkey milk through bioactivities that are important for human health.


Assuntos
Antibacterianos/farmacologia , Antivirais/farmacologia , Fermentação , Lactobacillus rhamnosus/fisiologia , Lactococcus/fisiologia , Leite/microbiologia , Sequência de Aminoácidos , Animais , Antioxidantes/farmacologia , Quelantes/farmacologia , Equidae , Proteínas do Leite/análise , Peptídeos/química , Peptídeos/farmacologia
6.
Molecules ; 26(16)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34443615

RESUMO

The aim of this study was to analyze the microbiome of raw milk obtained from three semi-subsistence farms (A, B, and C) located in the Kuyavian-Pomeranian Voivodeship in Poland. The composition of drinking milk was assessed on the basis of 16S rRNA gene sequencing using the Ion Torrent platform. Based on the conducted research, significant changes in the composition of the milk microbiome were found depending on its place of origin. Bacteria belonging to the Bacillus (17.0%), Corynebacterium (12.0%) and Escherichia-Shigella (11.0%) genera were dominant in the milk collected from farm A. In the case of the milk from farm B, the dominant bacteria belonged to the Acinetobacter genus (21.0%), whereas in the sample from farm C, Escherichia-Shigella (24.8%) and Bacillus (10.3%) dominated the microbiome. An analysis was performed using the PICRUSt tool (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) in order to generate a profile of genes responsible for bacterial metabolism. The conducted analysis confirmed the diversity of the profile of genes responsible for bacterial metabolism in all the tested samples. On the other hand, simultaneous analysis of six KEGG Orthologs (KO), which participated in beta-lactam resistance responsible for antibiotic resistance of bacteria, demonstrated that there is no significant relationship between the predicted occurrence of these orthologs and the place of existence of microorganisms. Therefore, it can be supposed that bacterial resistance to beta-lactam antibiotics occurs regardless of the environmental niche, and that the antibiotic resistance maintained in the population is a factor that shapes the functional structure of the microbial consortia.


Assuntos
Fazendas , Microbiota/genética , Leite/microbiologia , Sono de Ondas Lentas , Animais , Bactérias/genética , Bactérias/isolamento & purificação
7.
J Dairy Sci ; 104(10): 10594-10608, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34334205

RESUMO

Listeria monocytogenes is a ubiquitous pathogen that can cause morbidity and mortality in immunocompromised individuals. Growth of L. monocytogenes is possible at refrigeration temperatures due to its psychrotrophic nature. The use of antimicrobials in dairy products is a potential way to control L. monocytogenes growth in processes with no thermal kill step, thereby enhancing the safety of such products. Microbial-based enzymes offer a clean-label approach for control of L. monocytogenes outgrowth. Lactose oxidase (LO) is a microbial-derived enzyme with antimicrobial properties. It oxidizes lactose into lactobionic acid and reduces oxygen, generating H2O2. This study investigated the effects of LO in UHT skim milk using different L. monocytogenes contamination scenarios. These LO treatments were then applied to raw milk with various modifications; higher levels of LO as well as supplementation with thiocyanate were added to activate the lactoperoxidase system, a natural antimicrobial system present in milk. In UHT skim milk, concentrations of 0.0060, 0.012, and 0.12 g/L LO each reduced L. monocytogenes counts to below the limit of detection between 14 and 21 d of refrigerated storage, dependent on the concentration of LO. In the 48-h trials in UHT skim milk, LO treatments were effective in a concentration-dependent fashion. The highest concentration of LO in the 21-d trials, 0.12 g/L, did not show great inhibition over 48 h, so concentrations were increased for these experiments. In the lower inoculum, after 48 h, a 12 g/L LO treatment reached levels of 1.7 log cfu/mL, a reduction of 1.3 log cfu/mL from the initial inoculum, whereas the control grew out to approximately 4 log cfu/mL, an increase of 1 log cfu/mL from the inoculum on d 0. When a higher challenge inoculum of 5 log cfu/mL was used, the 0.12 g/L and 1.2 g/L treatments reduced the levels by 0.2 to 0.3 log cfu/mL below the initial inoculum and the 12 g/L treatment by >1 log cfu/mL below the initial inoculum by hour 48 of storage at refrigeration temperatures. After the efficacy of LO was determined in UHT skim milk, LO treatments were applied to raw milk. Concentrations of LO were increased, and the addition of thiocyanate was investigated to supplement the effect of the lactoperoxidase system against L. monocytogenes. When raw milk was inoculated with 2 log cfu/mL, 1.2 g/L LO alone and combined with sodium thiocyanate reduced ~0.8 log cfu/mL from the initial inoculum on d 7 of storage, whereas the control grew out to >1 log cfu/mL from the initial inoculum. Furthermore, in the higher inoculum, 1.2 g/L LO combined with sodium thiocyanate reduced L. monocytogenes counts from the initial inoculum by >1 log cfu/mL, whereas the control grew out 2 log cfu/mL from the initial inoculum. Results from this study suggest that LO is inhibitory against L. monocytogenes in UHT skim milk and in raw milk. Therefore, LO may be an effective treatment to prevent L. monocytogenes outgrowth, increase the safety of raw milk, and be used as an effective agent to prevent L. monocytogenes proliferation in fresh cheese and other dairy products. This enzymatic approach is a novel application to control the foodborne pathogen L. monocytogenes in dairy products.


Assuntos
Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Listeria monocytogenes , Leite/microbiologia , Animais , Desidrogenases de Carboidrato , Contagem de Colônia Microbiana/veterinária , Conservação de Alimentos , Peróxido de Hidrogênio
8.
Int J Mol Sci ; 22(16)2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34445321

RESUMO

Listeria monocytogenes is an important food-borne pathogen and a serious concern to food industries. Bacteriocins are antimicrobial peptides produced naturally by a wide range of bacteria mostly belonging to the group of lactic acid bacteria (LAB), which also comprises many strains used as starter cultures or probiotic supplements. Consequently, multifunctional strains that produce bacteriocins are an attractive approach to combine a green-label approach for food preservation with an important probiotic trait. Here, a collection of bacterial isolates from raw cow's milk was typed by 16S rRNA gene sequencing and MALDI-Biotyping and supernatants were screened for the production of antimicrobial compounds. Screening was performed with live Listeria monocytogenes biosensors using a growth-dependent assay and pHluorin, a pH-dependent protein reporting membrane damage. Purification by cation exchange chromatography and further investigation of the active compounds in supernatants of two isolates belonging to the species Pediococcus acidilactici and Lactococcus garvieae suggest that their antimicrobial activity is related to heat-stable proteins/peptides that presumably belong to the class IIa bacteriocins. In conclusion, we present a pipeline of methods for high-throughput screening of strain libraries for potential starter cultures and probiotics producing antimicrobial compounds and their identification and analysis.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Descoberta de Drogas/métodos , Listeria monocytogenes/efeitos dos fármacos , Probióticos , Animais , Antibacterianos/biossíntese , Bacteriocinas/biossíntese , Lactococcus/isolamento & purificação , Lactococcus/metabolismo , Microbiota , Leite/microbiologia , Pediococcus acidilactici/isolamento & purificação , Pediococcus acidilactici/metabolismo
9.
Molecules ; 26(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34361753

RESUMO

The popularity and consumption of fermented milk products are growing. On the other hand, consumers are interested in health-promoting and functional foods. Fermented milk products are an excellent matrix for the incorporation of bioactive ingredients, making them functional foods. To overcome the instability or low solubility of many bioactive ingredients under various environmental conditions, the encapsulation approach was developed. This review analyzes the fortification of three fermented milk products, i.e., yogurt, cheese, and kefir with bioactive ingredients. The encapsulation methods and techniques alongside the encapsulant materials for carotenoids, phenolic compounds, omega-3, probiotics, and other micronutrients are discussed. The effect of encapsulation on the properties of bioactive ingredients themselves and on textural and sensory properties of fermented milk products is also presented.


Assuntos
Queijo/análise , Tecnologia de Alimentos/métodos , Alimento Funcional/análise , Kefir/análise , Leite/metabolismo , Iogurte/análise , Animais , Carotenoides/administração & dosagem , Carotenoides/química , Ácidos Graxos Ômega-3/administração & dosagem , Fermentação , Aditivos Alimentares/administração & dosagem , Humanos , Lactobacillaceae/fisiologia , Micronutrientes/administração & dosagem , Leite/química , Leite/microbiologia , Fenóis/administração & dosagem , Fenóis/química , Probióticos/administração & dosagem
10.
Arch Virol ; 166(10): 2887-2894, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34347170

RESUMO

The complete genome sequence of the virulent bacteriophage PMBT3, isolated on the proteolytic Pseudomonas grimontii strain MBTL2-21, showed no significant similarity to other known phage genome sequences, making this phage the first reported to infect a strain of P. grimontii. Electron microscopy revealed PMBT3 to be a member of the family Siphoviridae, with notably long and flexible whiskers. The linear, double-stranded genome of 87,196 bp has a mol% G+C content of 60.4 and contains 116 predicted protein-encoding genes. A putative tellurite resistance (terB) gene, originally reported to occur in the genome of a bacterium, was detected in the genome of phage PMBT3.


Assuntos
Pseudomonas/virologia , Animais , Bacteriólise , Composição de Bases , Sequência de Bases , DNA Viral/genética , Genoma Viral/genética , Especificidade de Hospedeiro , Leite/microbiologia , Filogenia , Fagos de Pseudomonas/classificação , Fagos de Pseudomonas/genética , Fagos de Pseudomonas/fisiologia , Fagos de Pseudomonas/ultraestrutura , Siphoviridae/classificação , Siphoviridae/genética , Siphoviridae/fisiologia , Siphoviridae/ultraestrutura , Proteínas Virais/genética , Vírion/ultraestrutura
11.
Int J Food Microbiol ; 354: 109318, 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34246014

RESUMO

The presence of mesophilic and thermophilic spore-forming bacteria in UHT milk, as well as biofilm formation in dairy plants, are concerning. The current study explored the spore-forming bacilli diversity in 100 samples of UHT milk (skimmed and whole). Through this work, a total of 239 isolates from UHT milk samples were obtained. B. cereus s.s. was isolated from 7 samples, B. sporothermodurans from 19 and, G. stearothermophilus from 25 samples. Genes encoding hemolysin (HBL), and non-hemolytic (NHE) enterotoxins were detected in B. cereus s.s. isolates. All isolates of B. cereus s.s. (12) B. sporothermodurans (38), and G. stearothermophilus (47) were selected to verify the ability of biofilm formation in microtiter plates. The results showed all isolates could form biofilms. The OD595 values of biofilm formation varied between 0.14 and 1.04 for B. cereus, 0.20 to 1.87 for B. sporothermodurans, and 0.49 to 2.77 for G. stearothermophilus. The data highlights that the dairy industry needs to reinforce control in the initial quality of the raw material and in CIP cleaning procedures; avoiding biofilm formation and consequently a persistent microbiota in processing plants, which can shelter pathogenic species such as B. cereus s.s.


Assuntos
Bacillus cereus , Bacillus , Microbiologia de Alimentos , Geobacillus stearothermophilus , Temperatura Alta , Leite , Animais , Bacillus/genética , Bacillus/metabolismo , Bacillus cereus/genética , Bacillus cereus/metabolismo , Biofilmes , Geobacillus stearothermophilus/genética , Geobacillus stearothermophilus/metabolismo , Incidência , Leite/microbiologia
12.
J Dairy Res ; 88(3): 334-336, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34233770

RESUMO

This Research Communication describes the relation between somatic cells and microbial content in milk from Jersey cattle. Milk samples were classified in groups: healthy, dirty and mastitic (from Staphylococcus spp., Escherichia coli, Coliforms). The somatic cells in each of those groups were analysed by two methods - flow cytometric and automatic fluorescent cell counting. Those methods were compared. Total somatic cell count (SCC), neutrophil count, and lymphocytes with cluster of differentiation 4 (CD4+cells) were determined. There was a positive relationship between microbes and somatic cells. It was noticed that the neutrophil count was generally increased together with SCC, whilst the CD4+ cell count was higher in healthy milk samples (about 8%) compared to mastitic ones (about 3%). Lower number of CD4+ cells (from 1 to 4%) was determined in samples positive for Staphylococcus spp. but with lower SCC (from 2.7 to 4.0 × 105 cells/ml). Also, the number of CD4+ cells in Staphylococcus spp.-positive samples increased (to 4.8%) together with higher SCC, something that was not observed in the other mastitic samples. Knowledge of those relations could be useful for veterinary medical tests in the initial phase of inflammation.


Assuntos
Contagem de Linfócito CD4/veterinária , Contagem de Células/veterinária , Mastite Bovina/patologia , Leite/citologia , Neutrófilos , Animais , Carga Bacteriana/veterinária , Bovinos , Enterobacteriaceae/isolamento & purificação , Escherichia coli/isolamento & purificação , Feminino , Citometria de Fluxo/veterinária , Contagem de Leucócitos/veterinária , Mastite Bovina/microbiologia , Leite/microbiologia , Staphylococcus aureus/isolamento & purificação
13.
Biomed Res Int ; 2021: 5576873, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34327229

RESUMO

Staphylococcus aureus is a contagious pathogen that can cause various diseases in both humans and animals. Antimicrobial-resistant S. aureus is becoming an extremely important global health problem. A cross-sectional study was conducted from December 2019 to May 2020 to assess the occurrence of S. aureus and its antimicrobial susceptibility profiles in milk and traditionally processed dairy products in selected subcities of Addis Ababa. A total of 255 dairy product samples (175 raw milk and 80 traditionally processed dairy products) were collected from farms and retail markets. Samples were cultured for S. aureus according to standard microbiology techniques, and the Kirby-Bauer disk diffusion method was used to assess antimicrobial susceptibility of isolates to a panel of 12 antimicrobials. Susceptibility to methicillin was determined based on the sensitivity of isolates to cefoxitin, and resistant isolates were investigated for the presence of mecA and mecC genes using PCR. Staphylococcus aureus was isolated from 43 (24.6%) of milk, 7 (17.5%) of yogurt, and 2 (5%) of cottage cheese. A significantly higher rate of contamination with S. aureus was recorded among milk samples compared to yogurt and cottage cheese (p = 0.019). Out of 52 S. aureus isolates investigated for susceptibility to 12 antimicrobials, 49 (94.2%) of the isolates were resistant to ampicillin and 42 (80.8%) to amoxicillin+clavulanic acid. Twenty (38.5%) of the isolates were methicillin-resistant S. aureus (MRSA) based on susceptibility to cefoxitin. However, only one of these isolates (5%) was positive for mecA gene, and none of them were positive for the mecC gene. There was no significant difference (p > 0.05) in the rate of occurrence of MRSA among isolates from different sources. In conclusion, this study demonstrated a significant level of contamination of milk and dairy products with S. aureus and most isolates were multidrug resistant. The occurrence of MRSA in raw milk and dairy products signifies a serious public health threat as the practice of consuming raw dairy products in the study area is widespread. The lack of agreement between phenotypic and genotypic detection of MRSA suggests the need for further study to identify the genetic basis for the observed resistance phenotype.


Assuntos
Anti-Infecciosos/farmacologia , Laticínios/microbiologia , Leite/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Animais , Queijo/microbiologia , Etiópia , Geografia , Testes de Sensibilidade Microbiana , Prevalência , Staphylococcus aureus/isolamento & purificação , Iogurte/microbiologia
14.
Artigo em Inglês | MEDLINE | ID: mdl-34252020

RESUMO

Two strains of a Gram-staining-positive species were isolated from German bulk tank milk. On the basis of their 16S rRNA sequences they were affiliated to the genus Facklamia but could not be assigned to any species with a validly published name. Facklamia miroungae ATCC BAA-466T (97.3 % 16S rRNA sequence similarity), Facklamia languida CCUG 37842T (96.9 %), and Facklamia hominis CCUG 36813T (96.6 %) are the closest relatives. In the 16S rRNA phylogeny and in the core-genome phylogeny strains WS 5301T and WS 5302 form a well-supported, separate lineage. Pairwise average nucleotide identity calculated using MUMmer (ANIm) between WS 5301T and type strains of other Facklamia species is well below the species cut-off (95 %) and ranges from 83.4 to 87.7 %. The DNA G+C content of the type strain is 36.4 mol% and the assembly size of the genome is 2.2 Mb. Cells of WS 5301T are non-motile, non-endospore-forming, oxidase-negative, catalase-negative and facultatively anaerobic cocci. The fastidious species grows at 10-40 °C and with up to 7.0 % (w/v) NaCl in BHI supplemented with 5 g l-1 yeast extract. Major polar lipids are phosphatidylglycerol, diphosphatidylglycerol and two glycolipids. Predominant fatty acids are C16 : 1ω9c and C18 : 1ω9c. On the basis of their genomic, physiological and chemotaxonomic characteristics the strains examined in this study represent the same, hitherto unknown species. We propose the name Facklamia lactis sp. nov. for which WS 5301T (=DSM 111018T=LMG 31861T) is the type strain and WS 5302 (=DSM 111019=LMG 31862) is an additional strain of this novel species.


Assuntos
Aerococcaceae/classificação , Leite/microbiologia , Filogenia , Aerococcaceae/isolamento & purificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Bovinos , DNA Bacteriano/genética , Ácidos Graxos/química , Alemanha , Glicolipídeos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
15.
Recurso na Internet em Português | LIS - Localizador de Informação em Saúde | ID: lis-48246

RESUMO

O “Equipamento e método para detectar e discriminar adições pré-balanceadas no leite”, é um equipamento para identificar e discriminar adições no leite, que compreende uma estrutura compacta dotada de uma unidade de medição da condutividade alternada conjugada com uma unidade de medição de crioscopia, ditas unidades de medição de condutividade e de crioscopia, conectadas a um microcontrolador. A oferta da tecnologia prevê a exploração na modalidade exclusiva dos direitos de uso, produção, comercialização, relacionados à tecnologia de titularidade da UFJF.


Assuntos
Tecnologia de Alimentos , Leite/microbiologia
16.
Food Microbiol ; 99: 103803, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34119096

RESUMO

Tibetan kefir grains (TKG) are multi-functional starter cultures used in foods and have been applied in various fermentation systems. This study aimed to investigate the microbial community composition of TKG, the detoxification abilities of TKG and their isolates towards common mycotoxins, and the potential for applying TKG and their associated microbial populations to avoid mycotoxin contamination in dairy products. Cultivation-independent high-throughput sequencing of bacterial and fungal rDNA genes indicated that Lactobacillus kefiranofaciens and Kazachstania turicensis were the most abundant bacterial and fungal taxa, respectively. In addition, 27 total isolates were obtained using cultivation methods. TKG removed more than 90% of the Ochratoxin A (OTA) after 24 h, while the isolate Kazachstania unisporus AC-2 exhibited the highest removal capacity (~46.1%). Further, the isolate exhibited good resistance to acid and bile salts environment. Analysis of the OTA detoxification mechanism revealed that both adsorption and degradation activities were exhibited by TKG, with adsorption playing a major detoxification role. Furthermore, the addition of OTA did not affect the microbial community structure of TKG. These results indicate that TKG-fermented products can naturally remove mycotoxin contamination of milk and could potentially be practically applied as probiotics in fermentation products.


Assuntos
Kefir/microbiologia , Microbiota , Ocratoxinas/metabolismo , Animais , Biotransformação , Bovinos , Fermentação , Lactobacillus/classificação , Lactobacillus/genética , Lactobacillus/isolamento & purificação , Lactobacillus/metabolismo , Leite/microbiologia , Ocratoxinas/análise , Saccharomycetales/classificação , Saccharomycetales/genética , Saccharomycetales/isolamento & purificação , Saccharomycetales/metabolismo , Tibet
17.
Molecules ; 26(11)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071703

RESUMO

Staphylococcus aureus (S. aureus) is a major human pathogen that requires new antibiotics with unique mechanism. A new pleuromutilin derivative, 14-O-[(4,6-Diamino-pyrimidine-2-yl) thioacetyl] mutilin (DPTM), has been synthesized and proved as a potent antibacterial agent using in vitro and in vivo assays. In the present study, DPTM was further in vitro evaluated against methicillin-resistant Staphylococcus aureus (MRSA) isolated from dairy farms and outperformed tiamulin fumarate, a pleuromutilin drug used for veterinary. Moreover, a murine skin wound model caused by MRSA infection was established, and the healing effect of DPTM was investigated. The results showed that DPTM could promote the healing of MRSA skin infection, reduce the bacterial burden of infected skin MRSA and decrease the secretion of IL-6 and TNF-α inflammatory cytokines in plasma. These results provided the basis for further in-depth drug targeted studies of DPTM as a novel antibacterial agent.


Assuntos
Antibacterianos/farmacologia , Cetonas/química , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Compostos Policíclicos/química , Animais , Bovinos , Citocinas/metabolismo , Diterpenos/farmacologia , Desenho de Fármacos , Técnicas In Vitro , Inflamação , Interleucina-6/metabolismo , Leucócitos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Leite/microbiologia , Simulação de Acoplamento Molecular , Pele/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Fator de Necrose Tumoral alfa/biossíntese , Cicatrização
18.
Molecules ; 26(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34072808

RESUMO

The aim of the study was to assess the antioxidant potential of goat's milk and whey from goat's milk fermented with selected bacteria strains from kefir grain (L. plantarum, L. fermentum, L. rhamnosus and L. acidophilus) with regard to fermented cow's milk with the same bacteria strains. The assessment of antioxidant potential was made by ABTS, DPPH, TPC and FRAP methods. The work also assessed metabolic activity of tested lactic acid bacteria using measurement of electrical impedance changes in the growing medium. The highest values describing the antioxidant potential were found for fermented milk by L. acidophilus. It was also found that the time of cooling storage causes significantly increasing the antioxidant potential of most analyzed samples. Metabolic activity of tested lactic acid bacteria was the highest for cow's milk. The course of curves for goat's milk and whey from goat's milk was similar, which confirms the differences between cow and goat milk.


Assuntos
Antioxidantes/química , Fermentação , Análise de Alimentos/métodos , Kefir/microbiologia , Soro do Leite/microbiologia , Animais , Bactérias , Benzotiazóis/química , Reatores Biológicos , Compostos de Bifenilo/química , Bovinos , Técnicas de Química Analítica , Recuperação de Fluorescência Após Fotodegradação , Análise de Alimentos/instrumentação , Cabras , Ácido Láctico/química , Leite/microbiologia , Fenol/análise , Picratos/química , Proteólise , Especificidade da Espécie , Ácidos Sulfônicos/química , Temperatura , Proteínas do Soro do Leite
19.
Int J Food Microbiol ; 351: 109263, 2021 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-34116344

RESUMO

Campylobacter is the leading cause of foodborne human diarrhea worldwide. This microbe in the viable but non-culturable (VBNC) state can evade detection by routinely used culture-based methods and remain viable for extended periods of time. Bacteria in this dormancy state can resume their metabolic activity and virulence by resuscitation under favorable conditions, and subsequently cause infections. In this study, an assay combining loop-mediated isothermal amplification (LAMP) and propidium monoazide (PMA) treatment was developed for the detection and quantification of VBNC C. jejuni in agri-foods. PMA-qLAMP targeting the hipO gene demonstrated 100% high specificity to C. jejuni. A linear detection of C. jejuni was achieved between 8.77 × 102 and 8.77 × 07 CFU/mL with a coefficient of determination (R2) of 0.9956, indicating a good quantitative capacity. C. jejuni was effectively induced into the VBNC state by osmotic stress (i.e., 7% NaCl, w/v) over 48 h. VBNC C. jejuni cells were spiked into three representative food products and determined by PMA-qLAMP coupled with plating assay. The detection limits of PMA-qLAMP were 1.58 × 102 CFU/mL in milk, 3.78 × 102 CFU/g in chicken breast meat, and 4.33 × 102 CFU/g in romaine lettuce. PMA-qLAMP demonstrated rapid (25-40 min), specific (100% inclusivity and 100% exclusivity) and sensitive (~102 CFU/mL) determination of VBNC C. jejuni. This method can be applied in the agri-food industry to decrease the risks related to the consumption of contaminated agri-foods with pathogenic bacteria in the VBNC state and reduce the burden of C. jejuni infections to public health.


Assuntos
Campylobacter jejuni/isolamento & purificação , Microbiologia de Alimentos/métodos , Animais , Azidas , Campylobacter jejuni/genética , Galinhas , Genes Bacterianos/genética , Substâncias Intercalantes , Alface/microbiologia , Leite/microbiologia , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , Aves Domésticas/microbiologia , Propídio/análogos & derivados , Sensibilidade e Especificidade
20.
Artigo em Inglês | MEDLINE | ID: mdl-34161222

RESUMO

A novel Gram-stain-positive bacterium was isolated from a purulent bovine milk sample, the bovine placenta from an abortion, the udder secretion of a heifer and the lung of a pig that had succumbed from suppurative bronchopneumonia in Switzerland from 2015 to 2019. The strains grew best under aerobic conditions with 5 % CO2 and colonies were non-haemolytic and greyish-white. They were non-motile and negative for catalase and oxidase. The genomes of the four strains 19M2397T, 15A0121, 15IMD0307 and 19OD0592 were obtained by sequencing. The results of phylogenetic analyses based on the 16S rRNA gene grouped them within the genus Trueperella in the family Arcanobacteriaceae. The genomes had DNA G+C contents of 61.2-62.2 mol% and showed digital DNA-DNA hybridization (dDDH) values of 21.4-22.8 % and average nucleotide identity (ANI) values of approximately 77 % to their closest relatives Trueperella pyogenes and Trueperella bernardiae. With respect to the presence in different livestock species we propose the name Trueperella pecoris sp. nov. The type strain is 19M2397T (=CCOS 1952T=DSM 111392T), isolated from the udder secretion of a heifer diagnosed with summer mastitis in 2019.


Assuntos
Actinomycetaceae/classificação , Bovinos/microbiologia , Leite/microbiologia , Filogenia , Placenta/microbiologia , Suínos/microbiologia , Actinomycetaceae/isolamento & purificação , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Feminino , Hibridização de Ácido Nucleico , Gravidez , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Suíça
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