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1.
ISME J ; 17(9): 1504-1516, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37524910

RESUMO

Experimental studies of microbial evolution have largely focused on monocultures of model organisms, but most microbes live in communities where interactions with other species may impact rates and modes of evolution. Using the cheese rind model microbial community, we determined how species interactions shape the evolution of the widespread food- and animal-associated bacterium Staphylococcus xylosus. We evolved S. xylosus for 450 generations alone or in co-culture with one of three microbes: the yeast Debaryomyces hansenii, the bacterium Brevibacterium aurantiacum, and the mold Penicillium solitum. We used the frequency of colony morphology mutants (pigment and colony texture phenotypes) and whole-genome sequencing of isolates to quantify phenotypic and genomic evolution. The yeast D. hansenii strongly promoted diversification of S. xylosus. By the end of the experiment, all populations co-cultured with the yeast were dominated by pigment and colony morphology mutant phenotypes. Populations of S. xylosus grown alone, with B. aurantiacum, or with P. solitum did not evolve novel phenotypic diversity. Whole-genome sequencing of individual mutant isolates across all four treatments identified numerous unique mutations in the operons for the SigB, Agr, and WalRK global regulators, but only in the D. hansenii treatment. Phenotyping and RNA-seq experiments highlighted altered pigment and biofilm production, spreading, stress tolerance, and metabolism of S. xylosus mutants. Fitness experiments revealed antagonistic pleiotropy, where beneficial mutations that evolved in the presence of the yeast had strong negative fitness effects in other biotic environments. This work demonstrates that bacterial-fungal interactions can have long-term evolutionary consequences within multispecies microbiomes by facilitating the evolution of strain diversity.


Assuntos
Saccharomyces cerevisiae , Staphylococcus , Animais , Staphylococcus/genética , Bactérias , Interações Microbianas , Fungos
2.
Curr Microbiol ; 80(5): 176, 2023 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-37029832

RESUMO

Antimicrobial resistance is a natural phenomenon and is becoming a huge global public health problem, since some microorganisms not respond to the treatment of several classes of antibiotics. The objective of the present study was to evaluate the antibacterial, antibiofilm, and synergistic effect of triterpene 3ß,6ß,16ß-trihydroxyilup-20(29)-ene (CLF1) against Staphylococcus aureus and Staphylococcus epidermidis strains. Bacterial susceptibility to CLF1 was evaluated by minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) assay. In addition, the effect combined with antibiotics (ampicillin and tetracycline) was verified by the checkerboard method. The biofilms susceptibility was assessed by enumeration of colony-forming units (CFUs) and quantification of total biomass by crystal violet staining. The compound showed bacteriostatic and bactericidal activity against all Staphylococcal strains tested. The synergistic effect with ampicillin was observed only for S. epidermidis strains. Moreover, CLF1 significantly inhibited the biofilm formation and disrupted preformed biofilm of the all strains. Scanning electron microscopy (SEM) images showed changes in the cell morphology and structure of S. aureus ATCC 700698 biofilms (a methicillin-resistant S. aureus strain). Molecular docking simulations showed that CLF1 has a more favorable interaction energy than the antibiotic ampicillin on penicillin-binding protein (PBP) 2a of MRSA, coupled in different regions of the protein. Based on the results obtained, CLF1 proved to be a promising antimicrobial compound against Staphylococcus biofilms.


Assuntos
Combretum , Staphylococcus aureus Resistente à Meticilina , Triterpenos , Staphylococcus aureus , Combretum/química , Staphylococcus , Triterpenos/farmacologia , Simulação de Acoplamento Molecular , Extratos Vegetais/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Ampicilina/farmacologia , Biofilmes , Staphylococcus epidermidis , Testes de Sensibilidade Microbiana
3.
Int J Food Microbiol ; 375: 109744, 2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-35660256

RESUMO

Penicillium nordicum is the main ochratoxin A (OTA) producing mould in dry-cured meat products. The use of autochthonous microorganisms as protective cultures is a promising strategy to control this hazard. The aim of this work was to evaluate the effect of Debaryomyces hansenii and Staphylococcus xylosus isolated from dry-cured meat products as biocontrol agents (BCAs) against P. nordicum during the ripening of dry-cured fermented sausages. The BCAs were added to the dough, and P. nordicum were inoculated on the surface after stuffing. Then, the sausages were ripened following a traditional processing. The growth of the microorganisms was determined by plate count at the beginning and at the end of ripening. To assess the implantation of BCAs in the sausages, the yeasts and staphylococci isolated from the sausages at the end of processing were identified by sequencing the 16S and 18S rRNA respectively, and they were characterized by pulsed field gel electrophoresis (PFGE) of the chromosomal DNA. OTA was quantified by UHPLC-MS/MS. BCAs were able to colonise and develop throughout the processing. Although none of the BCAs reduced the growth of P. nordicum, a OTA decrease was observed in the sausages inoculated with D. hansenii individually or combined with S. xylosus. The drop of OTA amount was particularly marked in the portions where the casing was damaged allowing the mould to grow inside the sausages. In these areas, OTA was not detected in the inoculated batches. In conclusion, D. hansenii could be proposed as BCA individually or in combination with S. xylosus for the biocontrol of OTA hazard in dry-cured fermented sausages.


Assuntos
Debaryomyces , Produtos da Carne , Penicillium , Microbiologia de Alimentos , Fungos , Produtos da Carne/análise , Staphylococcus , Espectrometria de Massas em Tandem
4.
J Dairy Sci ; 104(7): 7500-7508, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33838885

RESUMO

Époisses is a protected designation of origin smear-ripened cheese from the Burgundy region in France. It has an orange color and a strong flavor, both of which are generated by surface microorganisms. The objective of the present study was to investigate the microbial dynamics at the surface of Époisses cheese during ripening and postmanufacturing storage at low temperatures. Rind samples were analyzed by enumeration on agar plates and by 16S rRNA gene and internal transcribed spacer amplicon sequencing. During most of the ripening process, the counts of yeasts, which corresponded to the species Debaryomyces hansenii and Geotrichum candidum, were higher than those of the aerobic acid-sensitive bacteria. Debaryomyces hansenii reached a level of about 3 × 108 cfu/cm2, and its viability strongly decreased in the late stage of ripening and during storage at 4°C. Two of the inoculated bacterial species, Brevibacterium aurantiacum and Staphylococcus xylosus, did not establish themselves at the cheese surface. At the end of ripening, among the 18 most abundant bacterial species detected by amplicon sequencing, 14 were gram-negative, mainly from genera Psychrobacter, Vibrio, Halomonas, and Mesonia. It was hypothesized that the high moisture level of the Époisses rinds, due the humid atmosphere of the ripening rooms and to the frequent washings of the curds, favored growth of these gram-negative species. These species may be of interest for the development of efficient ripening cultures. In addition, because the orange color of Époisses cheeses could not be attributed to the growth of Brevibacterium, it would be interesting to investigate the type and origin of the pigments that confer color to this cheese.


Assuntos
Queijo , Animais , Brevibacterium , França , Geotrichum , RNA Ribossômico 16S/genética , Staphylococcus
5.
Food Sci Technol Int ; 25(4): 327-336, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30669863

RESUMO

The aim of this study was to evaluate the effect of two protective lactic acid bacteria cultures combined with modified atmosphere packaging on the survival/growth of Listeria innocua 2030c (as a surrogate for Listeria monocytogenes) and on sensory attributes of ready-to-eat 'lombo' over storage time. Sliced 'lombo', a traditional cured-smoked pork loin, was inoculated with L. innocua 2030c, Lactobacillus sakei ST153 (isolated from 'salpicão') and BLC35 culture (with Lactobacillus curvatus, Staphylococcus xylosus and Pediococcus acidilactici; CHR Hansen) as protective cultures. Samples were packed in two modified atmosphere packaging conditions (20% CO2/80% N2 and 40% CO2/60% N2) and stored at 5 ℃ for 124 days. Both cultures led to a reduction of 1-2 log CFU/g of L. innocua 2030c after 12 h; however, at the end of storage only Lb. sakei ST153 maintained this antilisterial effect, which was more evident at 40% CO2/60% N2. The influence of cultures addition and modified atmosphere packaging conditions on the sensory characteristics of the product were not significant. Thus, Lb. sakei ST153 combined with modified atmosphere packaging is a strong candidate to be used in a biopreservation strategy maintaining the traditional sensory quality of cured-smoked pork products and increasing their safety with respect to Listeria spp.


Assuntos
Microbiologia de Alimentos , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Produtos da Carne/microbiologia , Carne Vermelha/microbiologia , Animais , Atmosfera , Bacteriocinas , Contagem de Colônia Microbiana , Contaminação de Alimentos , Lactobacillales/fisiologia , Lactobacillus/fisiologia , Listeria/crescimento & desenvolvimento , Listeria monocytogenes/crescimento & desenvolvimento , Pediococcus acidilactici/fisiologia , Fumaça , Staphylococcus/fisiologia , Suínos , Vácuo
6.
Meat Sci ; 123: 1-7, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27579788

RESUMO

Yeast inoculation of dry fermented sausages manufactured with entire male fat was evaluated as a strategy to improve sausage quality. Four different formulations with entire male/gilt back fat and inoculated/non-inoculated with Debaryomyces hansenii were manufactured. The use of entire male back fat produced the highest weight losses, hardness and chewiness in dry sausages. Consumers clearly distinguished samples according to drying time and D. hansenii inoculation while the use of entire/gilt back fat was not highly perceived. The presence of androstenone and skatole was close to their sensory thresholds. Androstenone was not degraded during the process but skatole was affected by yeast inoculation. D. hansenii growth on the surface regulated water release during ripening, reduced hardness and chewiness in entire male sausages and resulted with similar texture to gilt sausages. Yeast inoculation inhibited lipid oxidation providing fruity odours and less oxidized fatty sausages in the sensory analysis. The effectiveness of yeast to mask boar taint was demonstrated by sensory analysis.


Assuntos
Tecido Adiposo/química , Produtos da Carne/análise , Saccharomycetales , Leveduras , Adulto , Androsterona/análise , Cor , Comportamento do Consumidor , Dessecação , Gorduras na Dieta/análise , Feminino , Microbiologia de Alimentos , Qualidade dos Alimentos , Humanos , Lactobacillus , Masculino , Pessoa de Meia-Idade , Escatol/química , Olfato , Cloreto de Sódio na Dieta/análise , Staphylococcus , Paladar , Substâncias Reativas com Ácido Tiobarbitúrico/análise
7.
Pak J Biol Sci ; 11(20): 2372-81, 2008 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-19137845

RESUMO

This study determined the distribution of a specific group of Simple Sequence Repeats (SSRs), in genome sequences of 7 chromosomes (Shigella flexneri 2a str 301 and 2457 T, Shigella sonnei, E. coli K12, M. tuberculosis, M. leprae and S. saprophytycus) have downloaded from the GenBank database for identifying abundance, distribution and composition of SSRs. The data obtained in the present study show that: (i) Tandem repeats are widely distributed throughout the genomes. (ii) SSRs are differentially distributed among coding and non-coding regions in investigated Shigella genomes. (iii) Total frequency of SSRs in non-coding regions is higher than coding regions. (iv) In all investigated chromosomes ratio of Tri-nucleotide SSRs are much higher than randomized genomes and Di nucleotide SSRs are lower. (v) Ratio of total and mono-nucleotide SSRs in real genome is higher than randomized genomes in E. coli K12, Sh. flexneri str 301 and S. saprophyticus, while it is lower in Sh. flexneri str 2457T, Sh. sonnei and M. tuberculosis and it is approximately same in M. leprae. (vi) Frequency of codon repetitions are vary considerably depending on the type of encoded amino acid.


Assuntos
Bactérias/genética , Genoma Bacteriano , Repetições Minissatélites , Cromossomos Bacterianos/genética , DNA Bacteriano/genética , Escherichia coli K12/genética , Mycobacterium leprae/genética , Mycobacterium tuberculosis/genética , Shigella flexneri/genética , Shigella sonnei/genética , Staphylococcus/genética
8.
Int J Food Microbiol ; 120(1-2): 136-45, 2007 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-17628130

RESUMO

We have investigated the bacteria and yeast ecology of the typical Italian Ciauscolo salami that is produced in Central Italy using a polyphasic approach based on culture-dependent and -independent methods. The physico-chemical analyses showed a progressive drop in pH and water activity (aw) during ripening. The viable counts revealed a dominance of lactic acid bacteria (LAB) over coagulase negative cocci (CNC) and yeasts. From the molecular identification of the isolates, the prevalence of Lactobacillus curvatus, Lb. plantarum and Staphylococcus xylosus was shown among the bacteria, while Debaryomyces hansenii was the prevalent species among the yeasts, and it was isolated throughout the whole ripening process. Minority species, namely Rhodotorula mucillaginosa and Trichosporon brassicae, were also recovered from the meat batter. The total microbial community was profiled without cultivation by analyzing the DNA that was directly extracted from the salami samples. Moreover, the cultivable community was profiled by analyzing the DNA recovered from bulk cells that were obtained by harvesting the colonies from serial-dilution agar plates. The 16S rRNA gene V1 and V3 regions were used as targets in the denaturing gradient gel electrophoresis (DGGE) profiling of the LAB and CNC communities, respectively, while the diversity and dynamics of the yeast population were assessed by analyzing a portion of the 28S rRNA gene. Our findings suggest that the microbial diversity of fermented meat products can be successfully investigated by this polyphasic approach that is based on the assessment of both the total and the cultivable community diversity.


Assuntos
Microbiologia de Alimentos , Lactobacillus/isolamento & purificação , Produtos da Carne/microbiologia , Staphylococcus/isolamento & purificação , Leveduras/isolamento & purificação , Contagem de Colônia Microbiana , DNA Bacteriano/análise , DNA Fúngico/análise , Eletroforese em Gel de Poliacrilamida/métodos , Fermentação , Concentração de Íons de Hidrogênio , Itália , Lactobacillus/genética , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Staphylococcus/genética , Água/metabolismo , Leveduras/genética
9.
Appl Environ Microbiol ; 73(17): 5453-63, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17616625

RESUMO

The microbial ecology of "soppressata of Vallo di Diano," a traditional dry fermented sausage from southern Italy, was studied by using both culture-dependent and culture-independent approaches. The ripened fermented sausages were characterized by high microbial loads of both staphylococci and lactobacilli. Using PCR-denaturing gradient gel electrophoresis (PCR-DGGE) targeting the variable V3 and V1 regions of the 16S rRNA gene and direct DNA sequencing, it was possible to identify Staphylococcus xylosus, S. succinus, and S. equorum among the staphylococci and Lactobacillus sakei and L. curvatus within the lactobacilli. Moreover, Debaryomyces hansenii was the main yeast species found by targeting the yeast 26S rRNA gene by PCR-DGGE. Selected strains of S. xylosus, L. sakei, and L. curvatus were characterized for their technological properties in the ripening conditions of the fermented sausages so as to select an autochthonous starter formulation. The selection included the determination of nitrate reductase, lipolytic, and antioxidant activity and proteolysis with myofibrillar and sarcoplasmic protein fractions. Such properties were evaluated in both in vitro and in situ assays; the latter were performed by using each strain as a starter in the laboratory-scale manufacture of soppressata of Vallo di Diano and by monitoring the microbiological and chemical changes at the end of ripening. The results show differences between the in vitro and in situ selection results and indicate that in situ evaluation of the technological performance of specific strains is better suited to selecting autochthonous starter cultures for fermented-meat products than in vitro evaluation.


Assuntos
Ecossistema , Lactobacillus/classificação , Lactobacillus/isolamento & purificação , Produtos da Carne/microbiologia , Staphylococcus/classificação , Staphylococcus/isolamento & purificação , Biotecnologia/métodos , Contagem de Colônia Microbiana , Meios de Cultura , Eletroforese em Gel de Campo Pulsado , Fermentação , Itália , Lactobacillus/genética , Lactobacillus/metabolismo , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/genética , Saccharomycetales/classificação , Saccharomycetales/genética , Saccharomycetales/isolamento & purificação , Staphylococcus/genética , Staphylococcus/metabolismo
10.
J Dairy Res ; 73(4): 441-8, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16978429

RESUMO

The growth of five bacteria isolated from red-smear cheeses, Brevibacterium aurantiacum, Corynebacterium casei, Corynebacterium variabile, Microbacterium gubbeenense and Staphylococcus saprophyticus in mixed cultures with Debaryomyces hansenii on aseptic model cheese curd at 10 and 14 degrees C was investigated. At both temperatures, C. casei and Micro. gubbeenense had a longer lag phase than C. variabile, Brevi. aurantiacum and Staph. saprophyticus. In all cultures, lactose was utilised first and was consumed more rapidly at 14 degrees C than at 10 degrees C, i.e., 6 d at 14 degrees C and 10 d at 10 degrees C. This utilisation coincided with the exponential growth of Deb. hansenii on the cheese surface. Lactate was also used as a carbon source and was totally consumed after 21 d at 14 degrees C and approximately 90% was consumed after 21 d at 10 degrees C regardless of the ripening culture. Small differences (<0.5 pH unit) in the surface-pH during ripening were noticeable between ripening cultures. Differences in the colour development of the mixed cultures with the yeast control were only noticeable after 15 d for Brevi. aurantiacum and after 21 d for the other bacteria. Regardless of the organisms tested, colour development and colour intensity were also greater at 14 degrees C than at 10 degrees C. This study has provided useful information on the growth and contribution to colour development of these bacteria on cheese.


Assuntos
Queijo/microbiologia , Fermentação , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Saccharomycetales/crescimento & desenvolvimento , Brevibacterium/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Cor , Corynebacterium/crescimento & desenvolvimento , Concentração de Íons de Hidrogênio , Saccharomycetales/metabolismo , Staphylococcus/crescimento & desenvolvimento , Temperatura , Fatores de Tempo
11.
J Appl Microbiol ; 101(3): 668-81, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16907817

RESUMO

AIMS: To determine the relationships between the major organisms from the cheese-making personnel and environment and the surface of a smear cheese. METHODS AND RESULTS: 360 yeast and 593 bacteria from the cheese surface, the dairy environment and the hands and arms of personnel were collected. Pulsed-field gel electrophoresis, repetitive sequence-based polymerase chain reaction and 16S rDNA sequencing were used for typing and identifying the bacteria, and mitochondrial DNA restriction fragment length polymorphism and Fourier-transform infrared spectroscopy for typing and identifying the yeast. The three most dominant bacteria were Corynebacterium casei, Corynebacterium variabile and Staphylococcus saprophyticus, which were divided into three, five and seven clusters, respectively, by macrorestriction analysis. The same clones from these organisms were isolated on the cheese surface, the dairy environment and the skin of the cheese personnel. Debaryomyces hansenii was the most dominant yeast. CONCLUSIONS: A 'house' microflora exists in the cheese plant. Although the original source of the micro-organisms was not identified, the brines were an important source of S. saprophyticus and D. hansenii and, additionally, the arms and hands of the workers the sources of C. casei and C. variabile. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first time that the major contribution of the house microflora to the ripening of a smear-ripened cheese has been demonstrated.


Assuntos
Queijo/microbiologia , Microbiologia de Alimentos , Biodiversidade , Contagem de Colônia Microbiana/métodos , Corynebacterium/genética , Corynebacterium/isolamento & purificação , DNA Bacteriano/genética , DNA Mitocondrial/genética , DNA Ribossômico/genética , Eletroforese em Gel de Campo Pulsado/métodos , Manipulação de Alimentos/métodos , Indústria Alimentícia , Bactérias Gram-Positivas/genética , Bactérias Gram-Positivas/isolamento & purificação , Humanos , Fenótipo , Polimorfismo de Fragmento de Restrição , Pele/microbiologia , Staphylococcus/genética , Staphylococcus/isolamento & purificação , Local de Trabalho , Leveduras/genética , Leveduras/isolamento & purificação
12.
Artigo em Inglês | MEDLINE | ID: mdl-16766833

RESUMO

BACKGROUND: Banana leaf is used in many centers in India during the care of patients with toxic epidermal necrolysis (TEN) and other extensive blistering disorders. Sepsis is an important cause of death in TEN patients and use of banana leaf may be a source of such infection. AIMS: We conducted this study to detect the bacterial flora of the banana leaf and to examine various methods of rendering the leaf aseptic. METHODS: Five pieces of banana leaf, 2 x 2 cm in size, were cultured separately in blood agar as follows: One piece was heated over a flame and one was soaked in boiling water and one was autoclaved. Methylated spirit was applied over one piece and ignited. One piece was placed on the media, 'as is.' The Petri dishes were incubated examined after 48 h. RESULTS: All the pieces except the autoclaved specimen of the leaf grew coagulase-negative staphylococci (CONS) when aseptic precautions were not maintained and aerobic spore bearers when all aseptic measures were subsequently instituted during the procedure. CONCLUSION: We recommend measures to prevent possible transmission of bacterial infection by the leaf. Autoclaved and aseptically handled banana leaves may be used to reduce chance of infection in the treatment of TEN.


Assuntos
Assepsia/métodos , Terapias Complementares/métodos , Musa , Folhas de Planta , Síndrome de Stevens-Johnson/terapia , Humanos , Folhas de Planta/microbiologia , Staphylococcus/patogenicidade
13.
Syst Appl Microbiol ; 26(1): 30-7, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12747407

RESUMO

Two staphylococcal strains, RP29T and RP33, were isolated from the main microflora of a surface ripened Swiss mountain cheese made from raw milk. These two strains were differentiated from the most closely related species Staphylococcus equorum on the basis of DNA-DNA hybridisation and phenotypic characteristics and are proposed as Staphylococcus equorum subsp. linens subsp. nov. They could be distinguished phenotypically from S. equorum by their sensitivity to all 14 tested antibiotics, especially to novobiocin, their incapability to ferment alpha-D-lactose, maltose, sucrose, D-trehalose, D-xylose, L-arabinose, salicin, D-ribose, D-raffinose, D-mannitol, and D-alanine. The GenBank accession numbers for the reference sequences of the 16S rDNA and the hsp60 gene used in this study are AF527483 and AF527484, respectively. 30 tons of a semi-hard Swiss cheese were produced with Staphylococcus equorum subsp. linens DSM 15097T as starter culture component in addition to Debaryomyces hansenii, Geotrichum candidum, Brevibacterium linens, Corynebacterium casei for surface ripened cheeses. The products were sensorically and hygienically perfect. Therefore, Staphylococcus equorum subsp. linens DSM 15097T can be proposed as starter culture component for surface ripened cheeses without any detected antibiotic resistances. The type strain of Staphylococcus equorum subsp. linens is DSM 15097T (CIP 107656T).


Assuntos
Queijo/microbiologia , Microbiologia de Alimentos , Indústria de Processamento de Alimentos , Staphylococcus , Sequência de Aminoácidos , Composição de Bases , Fenômenos Bioquímicos , Meios de Cultura , Fermentação/fisiologia , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Peptidoglicano/análise , Filogenia , Reação em Cadeia da Polimerase/métodos , RNA Ribossômico 16S/análise , Alinhamento de Sequência , Análise de Sequência de DNA , Staphylococcus/classificação , Staphylococcus/genética , Staphylococcus/isolamento & purificação , Staphylococcus/ultraestrutura
14.
J Dairy Res ; 68(4): 663-74, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11928962

RESUMO

Volatile sulphur compounds are major flavouring compounds in many traditional fermented foods including cheeses. These compounds are products of the catabolism of L-methionine by cheese-ripening microorganisms. The diversity of L-methionine degradation by such microorganisms, however, remains to be characterized. The objective of this work was to compare the capacities to produce volatile sulphur compounds by five yeasts, Geotrichum candidum, Yarrowia lipolytica, Kluyveromyces lactis, Debaryomyces hansenii, Saccharomyces cerevisiae and five bacteria, Brevibacterium linens, Corynebacterium glutamicum, Arthrobacter sp., Micrococcus lutens and Staphylococcus equorum of technological interest for cheese-ripening. The ability of whole cells of these microorganisms to generate volatile sulphur compounds from L-methionine was compared. The microorganisms produced a wide spectrum of sulphur compounds including methanethiol, dimethylsulfide, dimethyldisulfide, dimethyltrisulfide and also S-methylthioesters, which varied in amount and type according to strain. Most of the yeasts produced methanethiol, dimethylsulfide, dimethyldisulfide and dimethyltrisulfide but did not produce S-methylthioesters, apart from G. candidum that produced S-methyl thioacetate. Bacteria, especially Arth. sp. and Brevi. linens, produced the highest amounts and the greatest variety of volatile sulphur compounds includling methanethiol, sulfides and S-methylthioesters, e.g. S-methyl thioacetate, S-methyl thiobutyrate, S-methyl thiopropionate and S-methyl thioisovalerate. Cell-free extracts of all the yeasts and bacteria were examined for the activity of enzymes possibly involved in L-methionine catabolism, i.e. L-methionine demethiolase, L-methionine aminotransferase and L-methionine deaminase. They all possessed L-methionine demethiolase activity, while some (K. lactis, Deb. hansenii, Arth. sp., Staph. equorum) were deficient in L-methionine aminotransferase, and none produced L-methionine deaminase. The catabolism of L-methionine in these microorganisms is discussed.


Assuntos
Queijo/microbiologia , Fermentação , Metionina/metabolismo , Arthrobacter/metabolismo , Brevibacterium/metabolismo , Liases de Carbono-Enxofre/metabolismo , Corynebacterium/metabolismo , Geotrichum/metabolismo , Kluyveromyces/metabolismo , Micrococcus luteus/metabolismo , Saccharomyces cerevisiae/metabolismo , Staphylococcus/metabolismo , Compostos de Enxofre/metabolismo , Transaminases/metabolismo , Volatilização , Yarrowia/metabolismo
15.
Int J Food Microbiol ; 32(1-2): 59-71, 1996 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8880328

RESUMO

The effects of environmental conditions on lipolysis by cell-free extracts from the meat starter culture organisms Staphylococcus xylosus and Debaryomyces hansenii were studied using pork fat emulsions as model systems. For the individual effects of temperature and pH it was found that the optimal conditions for the lipolysis by S. xylosus lipase were 37 degrees C and pH 7.0, and 37 degrees C and pH 6.5 for the lipolysis by D. hansenii lipase. For the combined effects of conditions relevant to meat fermentation, i.e. 10-30 degrees C, pH 4.7-6.0, 2.5-7.5% (w/v) NaCl and incubation times of 2-6 days, the empirical models indicated that temperature, pH and incubation time had important effects on total lipolysis whereas NaCl concentration had little effect. For both cultures lipolysis was strongly inhibited at conditions of meat fermentation compared to optimal conditions. For any set of the conditions which were examined the total lipolysis caused by D. hansenii lipase was lower than that caused by S. xylosus lipase.


Assuntos
Gorduras/metabolismo , Lipase/fisiologia , Lipólise , Carne/microbiologia , Staphylococcus/enzimologia , Temperatura , Animais , Concentração de Íons de Hidrogênio , Lipólise/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Suínos
16.
Postgrad Doc - Caribbean ; 11(6): 268-77, Dec. 1995.
Artigo em Inglês | MedCarib | ID: med-5032

RESUMO

Skin manifestations are a common feature of HTLV-1 associated disorders and of HTLV-1 infection itself. These include the lymphomatous skin infiltrates in adult T-cell lymphoma/leukaemia, most commonly manifesting as persistent, generalised papules, nodules and plaques with later ulceration, acquired ichthyosis and xeroderma in HAM/TSP, infective dermatitis of children, dermatomyositis, crusted (Norwegian) scabies, psoriasiform rashes which may precede one of the more serious disease associations, and possibly also seborrhoeic dermatitis. Disorders typically associated with immunosuppression such as disseminated herpes zoster, and ulcerative non-healing herpes simplex may also be seen occasionally both in ATK as well as in other wise asymptomatic HTLV-1 infection (AU)


Assuntos
Humanos , Masculino , Feminino , Criança , Adulto , Vírus Linfotrópico T Tipo 1 Humano , Linfoma Cutâneo de Células T , Dermatite , Dermatomiosite , Escabiose , Psoríase , Herpes Zoster , Herpes Simples , Leucemia-Linfoma de Células T do Adulto , Paraparesia Espástica Tropical , Uveíte , Hipercalcemia , Anemia , Complexo Relacionado com a AIDS , Hanseníase , Sarcoidose , Dermatite Esfoliativa , Escleroderma Sistêmico , Dermatopatias Vesiculobolhosas , Eczema , Ictiose , Imunoglobulina G , Anticorpos Anti-HTLV-I , Staphylococcus , Streptococcus , Bronquiectasia , Catarata , Polimiosite , Eritema , Edema , Sarcoptes scabiei , Dermatite Seborreica , Tinha do Couro Cabeludo , Região do Caribe , Estados Unidos , Haiti , Japão , América do Sul , África
17.
Acta Leprol ; 8(3): 143-7, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8213050

RESUMO

Swabs from 64 maggot infested leprosy ulcers before and after treatment for maggots and 100 non-infested leprosy ulcers were studied for the bacterial flora. From maggot infested ulcers (before treatment), the cultures usually showed mixed growth. Among the Gram positive isolates, Staphylococcus aureus (37%), S. albus (18%) and Streptococcus pyogenes (36%) were frequently isolated. Gram negative bacteria isolated were Proteus spp. (21%) and Escherichia coli (7%). Anaerobic bacteria isolated were Micrococcus (3%) and Bacteroides (4%). After treatment of maggot infested ulcers, S. aureus (36%) continued to be isolated with almost the same frequency. The isolates of other Gram negative organisms were slightly reduced. Among the Gram negatives the Proteus spp. (10%) were also less in number. In few cases Neisseria (3%) was found. Anaerobic isolates were M. luteus (2%) and B. necrophorus (3%). From the cases without maggot infestation, a single organism was isolated from 16 cases and 84 mixed cultures were obtained. Isolates included the aerobic Gram positives S. aureus (46%), S. albus (21%) and S. pyogenes (38%), and the Gram negative Proteus spp. (19%) and E. coli (7%). The anaerobic isolate was M. luteus (3%). From this study no apparent association between the type of bacterial flora and maggot infestation could be observed.


Assuntos
Bactérias/isolamento & purificação , Hanseníase/microbiologia , Hanseníase/parasitologia , Miíase/microbiologia , Úlcera Cutânea/microbiologia , Úlcera Cutânea/parasitologia , Bacteroides/isolamento & purificação , Corynebacterium/isolamento & purificação , Escherichia coli/isolamento & purificação , Humanos , Micrococcus/isolamento & purificação , Neisseria/isolamento & purificação , Proteus/isolamento & purificação , Proteus vulgaris/isolamento & purificação , Staphylococcus/isolamento & purificação , Staphylococcus aureus/isolamento & purificação , Streptococcus pyogenes/isolamento & purificação
18.
Lepr India ; 55(3): 504-11, 1983 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-6418969

RESUMO

Swabs from trophic ulcers from 108 cases were studied by culture. 37 cases yielded single organism (Ps. aeruginosa, 18, Proteus species 11, Staph. pyogenes 4, Others 4). 71 cases yielded mixed growth with two or more organisms. Ps. aeruginosa, Proteus species and Diphtheroids were the predominant organisms in these cultures. Ps. aeruginosa was sensitive to Gentamycin (96.6%), Streptomycin (62.7%) and Chloramphenicol (33.9%). Other organisms although comparatively more sensitive showed a similar pattern.


Assuntos
Doenças do Pé/microbiologia , Hanseníase/complicações , Úlcera Cutânea/microbiologia , Actinomycetales/isolamento & purificação , Antibacterianos/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/isolamento & purificação , Doenças do Pé/etiologia , Humanos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação , Úlcera Cutânea/etiologia , Staphylococcus/efeitos dos fármacos , Staphylococcus/isolamento & purificação , Streptococcus pyogenes/isolamento & purificação
19.
s.l; s.n; 1981. 10 p. ilus.
Não convencional em Inglês | SES-SP, HANSEN, HANSENIASE, SESSP-ILSLACERVO, SES-SP | ID: biblio-1240522

RESUMO

The histologic finding of variably acid-fast coccoid forms in all the available biopsy material (skin, lymph nodes, and lung) from a case of coexisting scleroderma-like cutaneous disease (hypodermitis sclerodermiformis) and systemic sarcoidosis is reported. The morphologic size, shape, and staining characteristics of these microbes, along with the presence of the lung of 'large bodies', suggest that these microbes are cell wall deficient L forms of mycobacteria. Culture of the skin of the scleroderma-like lesion yielded Staphylococcus epidermidis, and the relationship of this isolate to the histologic findings of bacteria is discussed, as well as the possible pathogenic role played by L forms of mycobacteria in collagen disease and systemic sarcoidosis.


Assuntos
Feminino , Humanos , Pessoa de Meia-Idade , Biópsia , Fasciite/microbiologia , Fasciite/patologia , Mycobacterium/isolamento & purificação , Pele/microbiologia , Pele/patologia , Sarcoidose/microbiologia , Sarcoidose/patologia , Staphylococcus/isolamento & purificação , Formas L , Pulmão/microbiologia , Pulmão/patologia
20.
Lepr India ; 49(3): 322-9, 1977 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-413005

RESUMO

39 consecutive cases of plantar ulcers with underlying chronic osteomyelitis admitted in the Sacred Heart Hospital during 1975/1976 were studied for the infecting organisms and their sensitivity to easily available antibiotics. Single organism was iasolated in only 10 cases, the infection in the rest being a mixed one. The commonest organisms were Staphylococcus, Streptococcus and Proteus mirabilis. In a few cases Pseudomonas and E-Coli were also isolated. Chloramphenicol was the most effective antibiotic in general and Streptomycin the least. 70% of the staphylococcus strains isolated were found to be resistant to Penicillin. Empirical use of antibiotics especially Penicillin and Streptomycin is hence deprecated.


Assuntos
Doenças do Pé/microbiologia , Hanseníase/complicações , Osteomielite/etiologia , Adolescente , Adulto , Idoso , Antibacterianos/farmacologia , Criança , Escherichia coli/efeitos dos fármacos , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Osteomielite/microbiologia , Proteus mirabilis/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus/efeitos dos fármacos , Streptococcus/efeitos dos fármacos , Úlcera/etiologia , Úlcera/microbiologia
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