Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 41
Filtrar
1.
J Glob Antimicrob Resist ; 19: 50-52, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31454564

RESUMO

OBJECTIVES: Here we report the draft genome sequence of Staphylococcus agnetis 3682, a strain producing agneticin 3682, a broad-spectrum lantibiotic with potential medical applications. The inhibitory activity of S. agnetis 3682 against multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA) isolates involved in human infections was also investigated. METHODS: A sequencing library was constructed using a Nextera XT DNA Library Preparation Kit. An Illumina MiSeq system was used to perform whole-genome shotgun sequencing. De novo genome assembly was performed using the A5-miseq pipeline. Staphylococcus agnetis 3628 genome annotation was performed by the RAST server, and BAGEL4 and antiSMASH v.4.0 platforms were used for mining bacteriocin gene clusters. The inhibitory activity of S. agnetis 3682 against 20 multidrug-resistant MRSA strains involved in human infections in two Brazilian hospitals was determined by the deferred antagonism assay on brain-heart infusion (BHI) agar plates. RESULTS: The total scaffold size was determined to be 2 502 817bp with a G+C content of 35.6%. Genome analyses revealed 2437 coding sequences, 76 RNA genes, 27 genes involved in drug resistance and 2 bacteriocinogenic gene clusters (for agneticin 3682 and hyicin 4244). Staphylococcus agnetis 3682 inhibited 80% of the MRSA isolates tested. CONCLUSION: This study describes the main features of the draft genome of S. agnetis 3682, a strain producing the first bacteriocin (agneticin 3682) reported in this species. A second gene cluster encoding a sactipeptide was also found in the bacterial chromosome. Agneticin 3682 shows a new potential application against clinical MRSA isolates.


Assuntos
Bacteriocinas/genética , Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus/genética , Staphylococcus/metabolismo , Antibacterianos/farmacologia , Composição de Bases , Sequência de Bases , Brasil , Farmacorresistência Bacteriana Múltipla/genética , Genes Bacterianos/genética , Genoma Bacteriano , Humanos , Testes de Sensibilidade Microbiana , Família Multigênica , Infecções Estafilocócicas/microbiologia , Staphylococcus/isolamento & purificação
2.
Int J Antimicrob Agents ; 51(3): 349-356, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28705677

RESUMO

Hyicin 4244 is a small antimicrobial peptide with a broad spectrum of activity that was found in the culture supernatant of Staphylococcus hyicus 4244, the genome of which was then sequenced. The bacteriocin gene cluster (hyiSABCDEFG) was mined from its single chromosome and exhibited a genetic organization similar to that of subtilosin A. All genes involved in hyicin 4244 biosynthesis proved to be transcribed and encode proteins that share at least 42% similarity to proteins encoded by the subtilosin A gene cluster. Due to its resemblance to subtilosin A and the presence of three thioether bonds in its structure, hyicin 4244 is assumed to be a 35-amino acid circular sactibiotic, the first to be described in staphylococci. Hyicin 4244 inhibited 14 staphylococcal isolates from either human infections or bovine mastitis, all biofilm formers. Hyicin 4244 significantly reduced the number of colony-forming units (CFU) and the biofilm formation by two strong biofilm-forming strains randomly chosen as representatives of the strains involved in human infections and bovine mastitis. It also reduced the proliferation and viability of sessile cells in established biofilms. Therefore, hyicin 4244 proved not only to prevent biofilm formation by planktonic cells, but also to penetrate the biofilm matrix in vitro, exerting bactericidal activity against staphylococcal sessile cells. This bacteriocin has the potential to become an alternative antimicrobial for either prevention or treatment of biofilm-related infections caused by different staphylococcal species.


Assuntos
Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Bacteriocinas/isolamento & purificação , Bacteriocinas/farmacologia , Biofilmes/efeitos dos fármacos , Staphylococcus/metabolismo , Animais , Vias Biossintéticas/genética , Bovinos , Contagem de Colônia Microbiana , Perfilação da Expressão Gênica , Humanos , Mastite Bovina/microbiologia , Viabilidade Microbiana/efeitos dos fármacos , Família Multigênica , Homologia de Sequência , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus/efeitos dos fármacos , Staphylococcus/isolamento & purificação
3.
World J Microbiol Biotechnol ; 33(8): 150, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28674925

RESUMO

The study of metal-tolerant bacteria is important for bioremediation of contaminated environments and development of green technologies for material synthesis due to their potential to transform toxic metal ions into less toxic compounds by mechanisms such as reduction, oxidation and/or sequestration. In this study, we report the isolation of seven lead-tolerant bacteria from a metal-contaminated site at Zacatecas, México. The bacteria were identified as members of the Staphylococcus and Bacillus genera by microscopic, biochemical and 16S rDNA analyses. Minimal inhibitory concentration of these isolates was established between 4.5 and 7.0 mM of Pb(NO3)2 in solid and 1.0-4.0 mM of Pb(NO3)2 in liquid media. A quantitative analysis of the lead associated to bacterial biomass in growing cultures, revealed that the percentage of lead associated to biomass was between 1 and 37% in the PbT isolates. A mechanism of complexation/biosorption of lead ions as inorganic phosphates (lead hydroxyapatite and pyromorphite) in bacterial biomass, was determined by Fourier transform infrared spectroscopy and X-ray diffraction analyses. Thus, the ability of the lead-tolerant isolates to transform lead ions into stable and highly insoluble lead minerals make them potentially useful for immobilization of lead in mining waste.


Assuntos
Bactérias/metabolismo , Imobilização , Chumbo/metabolismo , Sideróforos/metabolismo , Bacillus/isolamento & purificação , Bacillus/metabolismo , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Biodegradação Ambiental , Biomassa , Meios de Cultura/química , Chumbo/farmacologia , México , Minerais/metabolismo , Mineração , Nitratos/farmacologia , Fosfatos/metabolismo , Poluentes do Solo/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismo , Águas Residuárias , Difração de Raios X
4.
Microb Pathog ; 100: 312-318, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27725281

RESUMO

Coagulase-negative staphylococci (CNS) represent one of the most prevalent microorganisms in nosocomial infections worldwide, nevertheless little is known about their pathogenicity features. Thus, our aim was to characterize virulence aspects of CNS isolated from patients with bloodstream infections assisted in hospitals of Belo Horizonte, MG, Brazil. Strains were identified using bioMérieuxVitek® and for biofilm production evaluation, Congo Red Agar (CRA) and polystyrene plates were used. PCR was applied to detect icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr. For statistical analyses were used hierarchical cluster, chi-square test and correspondence. 59 strains were analyzed, being S. haemolyticus the most prevalent. On CRA, 96.5% were biofilm producer, whereas on polystyrene plate, 100% showed adhesion at different times evaluated. Regarding genotypic analyses, 15.2%, 38.9%, 8.4%, 49.1%, 76.2%, 23.7%, 1.6%, 30.5% and 38.9% were positive for icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr, respectively. Six clusters were formed and frequency distributions of agr, atlE, icaA, icaB, sea, sec, tsst-1 differed (P < 0.001). In conclusion, all strains were biofilm producer, with high prevalence of atlE, and had potential of toxin production, with high prevalence of sea. According to the group-analyses, icaB showed relationship with the strong adherence in samples.


Assuntos
Toxinas Bacterianas/análise , Biofilmes/crescimento & desenvolvimento , Sepse/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus/fisiologia , Aderência Bacteriana , Toxinas Bacterianas/genética , Técnicas de Tipagem Bacteriana , Brasil , Análise por Conglomerados , Infecção Hospitalar/microbiologia , Genótipo , Hospitais , Humanos , Reação em Cadeia da Polimerase , Staphylococcus/classificação , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismo , Fatores de Virulência/análise , Fatores de Virulência/genética
5.
Braz. j. microbiol ; Braz. j. microbiol;47(3): 675-679, July-Sept. 2016. tab, graf
Artigo em Inglês | LILACS | ID: lil-788961

RESUMO

ABSTRACT The need for cleaner sources of energy has stirred research into utilising alternate fuel sources with favourable emission and sustainability such as biodiesel. However, there are technical constraints that hinder the widespread use of some of the low cost raw materials such as pork fatty wastes. Currently available technology permits the use of lipolytic microorganisms to sustainably produce energy from fat sources; and several microorganisms and their metabolites are being investigated as potential energy sources. Thus, the aim of this study was to characterise the process of Staphylococcus xylosus mediated fermentation of pork fatty waste. We also wanted to explore the possibility of fermentation effecting a modification in the lipid carbon chain to reduce its melting point and thereby act directly on one of the main technical barriers to obtaining biodiesel from this abundant source of lipids. Pork fatty waste was obtained from slaughterhouses in southern Brazil during evisceration of the carcasses and the kidney casing of slaughtered animals was used as feedstock. Fermentation was performed in BHI broth with different concentrations of fatty waste and for different time periods which enabled evaluation of the effect of fermentation time on the melting point of swine fat. The lowest melting point was observed around 46 °C, indicating that these chemical and biological reactions can occur under milder conditions, and that such pre-treatment may further facilitate production of biodiesel from fatty animal waste.


Assuntos
Animais , Staphylococcus/metabolismo , Biocombustíveis , Fermentação , Resíduos Industriais , Biotransformação , Indústria Alimentícia , Carne Vermelha
6.
Braz J Microbiol ; 47(3): 675-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27266633

RESUMO

The need for cleaner sources of energy has stirred research into utilising alternate fuel sources with favourable emission and sustainability such as biodiesel. However, there are technical constraints that hinder the widespread use of some of the low cost raw materials such as pork fatty wastes. Currently available technology permits the use of lipolytic microorganisms to sustainably produce energy from fat sources; and several microorganisms and their metabolites are being investigated as potential energy sources. Thus, the aim of this study was to characterise the process of Staphylococcus xylosus mediated fermentation of pork fatty waste. We also wanted to explore the possibility of fermentation effecting a modification in the lipid carbon chain to reduce its melting point and thereby act directly on one of the main technical barriers to obtaining biodiesel from this abundant source of lipids. Pork fatty waste was obtained from slaughterhouses in southern Brazil during evisceration of the carcasses and the kidney casing of slaughtered animals was used as feedstock. Fermentation was performed in BHI broth with different concentrations of fatty waste and for different time periods which enabled evaluation of the effect of fermentation time on the melting point of swine fat. The lowest melting point was observed around 46°C, indicating that these chemical and biological reactions can occur under milder conditions, and that such pre-treatment may further facilitate production of biodiesel from fatty animal waste.


Assuntos
Biocombustíveis , Fermentação , Resíduos Industriais , Staphylococcus/metabolismo , Animais , Biotransformação , Indústria Alimentícia , Carne Vermelha
7.
J Clin Microbiol ; 54(5): 1372-5, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26912749

RESUMO

Staphylococcus chromogenes is one of the main coagulase-negative staphylococci isolated from mastitis of dairy cows. We describe S. chromogenes isolates that can clot plasma. Since the main pathogen causing mastitis is coagulase-positive Staphylococcus aureus, the coagulase-positive phenotype of S. chromogenes described here can easily lead to misidentification.


Assuntos
Coagulação Sanguínea , Coagulase/deficiência , Plasma/metabolismo , Staphylococcus/metabolismo , Animais , Bovinos , Mastite Bovina/diagnóstico , Mastite Bovina/microbiologia , Staphylococcus/classificação , Staphylococcus/isolamento & purificação
8.
Meat Sci ; 115: 41-4, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26820805

RESUMO

The performance of a mixed starter culture, SAS-1, comprised of the autochthonous strains Lactobacillus sakei ACU-2 and Staphylococcus vitulinus ACU-10, was evaluated into the production process of a traditional dry sausage. Microbiological, physicochemical and sensory analyses were carried out to accomplish this goal. Results showed an improvement in performance through the introduction of SAS-1; adding mixed starter culture rapidly decreased pH, inhibited the growth of contaminant microorganisms and enhanced the beneficial ones, diminished TBARS, and highlighted color and aroma attributes. However, most influential organoleptic descriptors among consumer acceptance were not affected by the addition of the starter. This starter culture would represent a valuable tool to improve the homogeneity of artisanal manufacture of this traditional food.


Assuntos
Microbiologia de Alimentos , Qualidade dos Alimentos , Produtos da Carne/microbiologia , Animais , Argentina , Fenômenos Químicos , Contagem de Colônia Microbiana , Comportamento do Consumidor , Fermentação , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Humanos , Concentração de Íons de Hidrogênio , Latilactobacillus sakei/metabolismo , Produtos da Carne/análise , Carne Vermelha/microbiologia , Staphylococcus/metabolismo , Suínos , Paladar
9.
Foodborne Pathog Dis ; 12(11): 921-5, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26352253

RESUMO

Food handlers carrying enterotoxin-producing Staphylococcus are a potential source of food poisoning. The aim of this study was to analyze genes encoding enterotoxins in coagulase-positive Staphylococcus (CoPS) and coagulase-negative Staphylococcus (CoNS) isolated from the anterior nostrils and hands of food handlers at a university restaurant in the city of Natal, Northeast Brazil. Thirty food handlers were screened for the study. The isolates were subjected to Gram staining, a bacitracin sensitivity test, mannitol fermentation, and catalase and coagulase tests. CoNS and CoPS strains were subsequently identified by a Vitek 2 System (BioMerieux, France) and various biochemical tests. Polymerase chain reaction was used to detect genes for enterotoxins A, B, C, D, E, G, H, and I (sea, seb, sec, sed, see, seg, seh, and sei) and a disc-diffusion method was used to determine susceptibility to several classes of antimicrobials. All food handlers presented staphylococci on their hands and/or noses. The study found 58 Staphylococcus spp., of which 20.7% were CoPS and 79.3% were CoNS. S. epidermidis was the most prevalent species. Twenty-nine staphylococci (50%) were positive for one or more enterotoxin genes, and the most prevalent genes were seg and sei, each with a frequency of 29.3%. Indeed, CoNS encoded a high percentage of enterotoxin genes (43.5%). However, S. aureus encoded even more enterotoxin genes (75%). Most isolates showed sensitivity to the antibiotics used for testing, except for penicillin (only 35% sensitive). The results from this study reinforce that coagulase-negative as well as coagulase-positive staphylococci isolated from food handlers are capable of genotypic enterotoxigenicity.


Assuntos
Enterotoxinas/genética , Manipulação de Alimentos , Genes Bacterianos/genética , Staphylococcus/isolamento & purificação , Antibacterianos/farmacologia , Bacitracina/farmacologia , Brasil , Enterotoxinas/isolamento & purificação , Mãos/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Nariz/microbiologia , Penicilinas/farmacologia , Restaurantes , Staphylococcus/efeitos dos fármacos , Staphylococcus/enzimologia , Staphylococcus/metabolismo , Universidades
10.
Curr Microbiol ; 71(5): 601-6, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26289722

RESUMO

The increasing rise in the production of meat around the world causes a significant generation of agro-industrial waste--most of it with a low value added. Fatty wastes have the potential of being converted into biodiesel, given the overcome of technological and economical barriers, as well as its presentation in solid form. Therefore, the aim of this work was to investigate the capacity of Staphylococcus xylosus strains to modify the chemical structure of chicken fatty wastes intending to reduce the melting points of the wastes to mild temperatures, thereby breaking new ground in the production of biodiesel from these sources in an economically attractive and sustainable manner. The effects in time of fermentation and concentration of the fat in the medium were investigated, assessing the melting point and profile of fatty acids. The melting temperature showed a decrease of approximately 22 °C in the best operational conditions, due to reduction in the content of saturated fatty acids (high melting point) and increase of unsaturated fatty acids (low melting point).


Assuntos
Ácidos Graxos Insaturados/metabolismo , Fermentação , Staphylococcus/metabolismo , Tecido Adiposo , Animais , Biocombustíveis , Galinhas , Ácidos Graxos Insaturados/química , Carne , Temperatura de Transição
11.
Braz J Microbiol ; 46(2): 347-54, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26273248

RESUMO

Halophilic microorganisms are able to grow in the presence of salt and are also excellent source of enzymes and biotechnological products, such as exopolysaccharides (EPSs) and polyhydroxyalkanoates (PHAs). Salt-tolerant bacteria were screened in the Organic Composting Production Unit (OCPU) of São Paulo Zoological Park Foundation, which processes 4 ton/day of organic residues including plant matter from the Atlantic Rain Forest, animal manure and carcasses and mud from water treatment. Among the screened microorganisms, eight halotolerant bacteria grew at NaCl concentrations up to 4 M. These cultures were classified based on phylogenetic characteristics and comparative partial 16S rRNA gene sequence analysis as belonging to the genera Staphylococcus, Bacillus and Brevibacterium. The results of this study describe the ability of these halotolerant bacteria to produce some classes of hydrolases, namely, lipases, proteases, amylases and cellulases, and biopolymers. The strain characterized as of Brevibacterium avium presented cellulase and amylase activities up to 4 M NaCl and also produced EPSs and PHAs. These results indicate the biotechnological potential of certain microorganisms recovered from the composting process, including halotolerant species, which have the ability to produce enzymes and biopolymers, offering new perspectives for environmental and industrial applications.


Assuntos
Bacillus/isolamento & purificação , Produtos Biológicos/análise , Brevibacterium/isolamento & purificação , Hidrolases/análise , Cloreto de Sódio/metabolismo , Microbiologia do Solo , Staphylococcus/isolamento & purificação , Bacillus/classificação , Bacillus/genética , Bacillus/metabolismo , Brasil , Brevibacterium/classificação , Brevibacterium/genética , Brevibacterium/metabolismo , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Solo , Staphylococcus/classificação , Staphylococcus/genética , Staphylococcus/metabolismo
12.
Braz. j. microbiol ; Braz. j. microbiol;46(2): 347-354, Apr-Jun/2015. tab, graf
Artigo em Inglês | LILACS | ID: lil-749729

RESUMO

Halophilic microorganisms are able to grow in the presence of salt and are also excellent source of enzymes and biotechnological products, such as exopolysaccharides (EPSs) and polyhydroxyalkanoates (PHAs). Salt-tolerant bacteria were screened in the Organic Composting Production Unit (OCPU) of São Paulo Zoological Park Foundation, which processes 4 ton/day of organic residues including plant matter from the Atlantic Rain Forest, animal manure and carcasses and mud from water treatment. Among the screened microorganisms, eight halotolerant bacteria grew at NaCl concentrations up to 4 M. These cultures were classified based on phylogenetic characteristics and comparative partial 16S rRNA gene sequence analysis as belonging to the genera Staphylococcus, Bacillus and Brevibacterium. The results of this study describe the ability of these halotolerant bacteria to produce some classes of hydrolases, namely, lipases, proteases, amylases and cellulases, and biopolymers. The strain characterized as of Brevibacterium avium presented cellulase and amylase activities up to 4 M NaCl and also produced EPSs and PHAs. These results indicate the biotechnological potential of certain microorganisms recovered from the composting process, including halotolerant species, which have the ability to produce enzymes and biopolymers, offering new perspectives for environmental and industrial applications.


Assuntos
Bacillus/isolamento & purificação , Produtos Biológicos/análise , Brevibacterium/isolamento & purificação , Hidrolases/análise , Microbiologia do Solo , Cloreto de Sódio/metabolismo , Staphylococcus/isolamento & purificação , Brasil , Bacillus/classificação , Bacillus/genética , Bacillus/metabolismo , Brevibacterium/classificação , Brevibacterium/genética , Brevibacterium/metabolismo , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dados de Sequência Molecular , Filogenia , /genética , Análise de Sequência de DNA , Solo , Staphylococcus/classificação , Staphylococcus/genética , Staphylococcus/metabolismo
13.
Braz. J. Microbiol. ; 46(2): 347-354, Apr.-Jun. 2015. tab, graf
Artigo em Inglês | VETINDEX | ID: vti-2241

RESUMO

Halophilic microorganisms are able to grow in the presence of salt and are also excellent source of enzymes and biotechnological products, such as exopolysaccharides (EPSs) and polyhydroxyalkanoates (PHAs). Salt-tolerant bacteria were screened in the Organic Composting Production Unit (OCPU) of São Paulo Zoological Park Foundation, which processes 4 ton/day of organic residues including plant matter from the Atlantic Rain Forest, animal manure and carcasses and mud from water treatment. Among the screened microorganisms, eight halotolerant bacteria grew at NaCl concentrations up to 4 M. These cultures were classified based on phylogenetic characteristics and comparative partial 16S rRNA gene sequence analysis as belonging to the genera Staphylococcus, Bacillus and Brevibacterium. The results of this study describe the ability of these halotolerant bacteria to produce some classes of hydrolases, namely, lipases, proteases, amylases and cellulases, and biopolymers. The strain characterized as of Brevibacterium avium presented cellulase and amylase activities up to 4 M NaCl and also produced EPSs and PHAs. These results indicate the biotechnological potential of certain microorganisms recovered from the composting process, including halotolerant species, which have the ability to produce enzymes and biopolymers, offering new perspectives for environmental and industrial applications.(AU)


Assuntos
Bacillus/isolamento & purificação , Produtos Biológicos/análise , Brevibacterium/isolamento & purificação , Hidrolases/análise , Cloreto de Sódio/metabolismo , Microbiologia do Solo , Staphylococcus/isolamento & purificação , Bacillus/classificação , Bacillus/genética , Bacillus/metabolismo , Brasil , Brevibacterium/classificação , Brevibacterium/genética , Brevibacterium/metabolismo , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Solo , Staphylococcus/classificação , Staphylococcus/genética , Staphylococcus/metabolismo
14.
Nat Prod Res ; 27(12): 1098-101, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-22703567

RESUMO

This study assessed the production of a bacteriocin-like substance by Staphylococcus pseudintermedius S28, and evaluates its inhibitory effect against isolates of S. aureus from foods. All indicator isolates were sensitive to the substance produced from S. pseudintermedius S28, showing growth inhibition zones ranging from 14.2 to 28.3 mm. The inhibitory substance has no effect against the producer strain. The inhibitory substance was affected by proteolytic enzymes, while glycolytic and lipolytic enzymes had no effect, suggesting that the active substance could be considered as a bacteriocin-like substance. From these results, S. pseudintermedius S28 could be an interesting producer of a bacteriocin-like substance capable of strongly inhibiting S. aureus.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus/metabolismo , Antibacterianos/isolamento & purificação , Staphylococcus/química , Staphylococcus/efeitos dos fármacos
15.
J Dairy Sci ; 94(3): 1194-200, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21338785

RESUMO

A collection of 111 staphylococcal isolates recovered from healthy cows in 41 dairy herds in Brazil was surveyed for the production of bacteriocins. The group included 94 coagulase-positive and 17 coagulase-negative strains of staphylococci. All cultures were grown in tryptic soy broth for 18h at 37°C, and cell-free supernatants were tested for antimicrobial activity against several target organisms by using the agar diffusion method. Filtrates of 57 staphylococci showed strong activity against Listeria monocytogenes Scott A, and 52 isolates also inhibited the growth of Stapylococcus aureus Newbould 305, a major causative agent of bovine mastitis in the United States. The plasmid profiles of staphylococci invariably included an 8-kb plasmid. Staphylococcal isolates were tested for the production of aureocins A70 and A53, 2 bacteriocins of coagulase-positive staphylococci known to be associated with 8-kb and 10.2-kb plasmids, respectively. The presence of the A70 or A53 bacteriocin gene was checked by PCR techniques using primers based on nucleotide sequences flanking the structural gene of each bacteriocin. Agarose gel analysis of amplified PCR products of plasmid templates from all 58 isolates showed only a 525-bp fragment corresponding to the structural gene of the bacteriocin aureocin A70. The results indicated that the apparently widespread association of A70-producing staphylococci with healthy cows in Brazil may be beneficial in controlling undesirable bacteria in dairy herds.


Assuntos
Antibacterianos/biossíntese , Bacteriocinas/biossíntese , Leite/microbiologia , Staphylococcus/metabolismo , Animais , Bacteriocinas/genética , Bovinos , Listeria monocytogenes/crescimento & desenvolvimento , Staphylococcus/isolamento & purificação , Staphylococcus aureus/crescimento & desenvolvimento
16.
Mem Inst Oswaldo Cruz ; 106(1): 44-50, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21340354

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative Staphylococcus spp (CNS) are the most common pathogens that cause serious long term infections in patients. Despite the existence of new antimicrobial agents, such as linezolid, vancomycin (VAN) remains the standard therapy for the treatment of infections caused by these multidrug-resistant strains. However, the use of VAN has been associated with a high frequency of therapeutic failures in some clinical scenarios, mainly with decreasing concentration of VAN. This work aims to evaluate the synergic potential of VAN plus sulfamethoxazole/trimethoprim (SXT), VAN plus rifampin (RIF) and VAN plus imipenem (IPM) in sub-minimum inhibitory concentrations against 22 clinical strains of MRSA and CNS. The checkerboard method showed synergism of VAN/RIF and VAN/SXT against two and three of the 22 strains, respectively. The combination of VAN with IPM showed synergistic effects against 21 out of 22 strains by the E-test method. Four strains were analyzed by the time-kill curve method and synergistic activity was observed with VAN/SXT, VAN/RIF and especially VAN/IPM in sub-inhibitory concentrations. It would be interesting to determine if synergy occurs in vivo. Evidence of in vivo synergy could lead to a reduction of the standard VAN dosage or treatment time.


Assuntos
Antibacterianos/farmacologia , Imipenem/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus/efeitos dos fármacos , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Vancomicina/farmacologia , Coagulase/metabolismo , Sinergismo Farmacológico , Humanos , Testes de Sensibilidade Microbiana , Staphylococcus/metabolismo
17.
Foodborne Pathog Dis ; 8(1): 159-63, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20807112

RESUMO

In this study, the enterotoxigenic potential of Staphylococcus strains (n = 574) isolated from raw milk samples (n = 140) was determined for their capacity to produce staphylococcal enterotoxins. In addition, the relationship between the presence of enterotoxins, coagulase, and thermonuclease (Tnase) was assessed. The results showed that 19% of Staphylococcus was enterotoxigenic, being able to produce at least one of the staphylococcal enterotoxins (A, B, C, and D). Most of the strains were able to produce enterotoxin D (68.8%), whereas 12.8% of the Staphylococcus strains were able to produce staphylococcal enterotoxin A. Besides, the production of more than one type of enterotoxins by the same strain was observed. Tnase was considered the best marker for enterotoxigenic potential of isolates, although some of them were negative for coagulase and Tnase but positive for enterotoxin production. Therefore, either the use of Tnase to assess Staphylococcus enterotoxigenic potential or the use of simple and easy screening tests for enterotoxin production should receive more attention when evaluating the pathogenic potential of foodborne Staphylococcus strains. Due to the association of both coagulase positive Staphylococcus and coagulase negative Staphylococcus with foodborne disease outbreaks, regulators and industries should pay more attention to enterotoxigenic Staphylococcus rather than focusing only on S. aureus or coagulase positive Staphylococcus. Finally, data found here suggest a high risk of staphylococcal intoxication with the consumption of raw milk or dairy products made from raw milk.


Assuntos
Coagulase/metabolismo , Enterotoxinas/análise , Nuclease do Micrococo/metabolismo , Leite/microbiologia , Staphylococcus/patogenicidade , Animais , Brasil , Microbiologia de Alimentos , Leite/química , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismo
18.
Vet Microbiol ; 146(1-2): 124-31, 2010 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-20627619

RESUMO

Nukacin 3299 (formerly designated simulancin 3299), produced by a Staphylococcus simulans strain involved in bovine mastitis in Brazil, is the first peptide bacteriocin described in this staphylococcal species. With the intent to elucidate some aspects of its biology, nukacin 3299 was purified and characterized. The mass of the purified bacteriocin was shown to be 2957.3 Da, and the peptide N-terminal amino acids (KKKSGVI) were identified by Edman degradation. The nukacin 3299 structural gene, nukA, was detected by PCR and DNA sequencing, showing that this bacteriocin is identical to nukacin ISK-1, a 27-amino acid type-A (II) lantibiotic produced by Staphylococcus warneri ISK-1, isolated from a "nukadoko", in Japan. The genes involved in nukacin 3299 biosynthesis are located on plasmid pRJ97 (>27 kb). They have an organization similar to that of the nukacin ISK-1 gene cluster, excepted for the presence of an IS257/431 element (791 bp) present between the orf1 and nukA genes of the nukacin 3299 gene cluster. The presence of this insertion sequence is expected to affect the expression of orf1, whose function is presently unknown. Nukacin 3299 proved to be sensitive to proteolytic enzymes and relatively stable at different temperatures and between pH 3.0-9.0. Nukacin 3299 exhibited activity towards staphylococcal strains involved in bovine mastitis, showing a potential application on mastitis control, a disease with great economic impact.


Assuntos
Bacteriocinas/genética , Staphylococcus/metabolismo , Animais , Bacteriocinas/biossíntese , Bacteriocinas/isolamento & purificação , Sequência de Bases , Bovinos , Clonagem Molecular , Feminino , Genes Bacterianos/genética , Mastite Bovina/microbiologia , Dados de Sequência Molecular , Família Multigênica/genética , Reação em Cadeia da Polimerase/veterinária , Alinhamento de Sequência/veterinária , Análise de Sequência de DNA , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/veterinária
19.
Foodborne Pathog Dis ; 7(9): 1121-3, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20528174

RESUMO

For a long time, Staphylococcus aureus has been always thought to be the only pathogenic species among Staphylococcus, while coagulase-negative staphylococci (CNS) were classified as contaminant agents. However, molecular techniques have shown that these microorganisms also possess enterotoxin-encoding genes. The aim of this study was to analyze the frequency of genes for staphylococcal enterotoxins SEA, SEB, SEC, and SED in CNS strains isolated from Minas soft cheese and to assess the in vitro production of toxins. CNS were found in 65 (72.2%) samples of cheese: 23 were Staphylococcus saprophyticus, 16 Staphylococcus warneri, 10 Staphylococcus epidermidis, 9 Staphylococcus xylosus, 3 Staphylococcus haemolyticus, 2 Staphylococcus schleiferi subsp. schleiferi, and 1 each Staphylococcus capitis subsp. urealyticus and Staphylococcus caprae. Seventeen (26.2%) CNS strains had genes for enterotoxins, and sea was more frequently found (18.5%), followed by sec in three and seb in two strains, whereas the sed gene was not found. S. saprophyticus showed enterotoxin genes in 6 of 23 isolates, but only sea was observed. On the other hand, five strains of S. warneri showed the sea, seb, or sec gene. In spite of the presence of these enterotoxin genes, these strains did not produce enterotoxins in vitro. It is essential to understand the real role of CNS in food, and based on the presence of enterotoxin genes, CNS should not be ignored in epidemiological investigations of foodborne outbreaks.


Assuntos
Queijo/microbiologia , Coagulase/análise , Enterotoxinas/genética , Microbiologia de Alimentos , Reação em Cadeia da Polimerase , Staphylococcus/genética , Brasil , DNA Bacteriano/análise , Enterotoxinas/biossíntese , Staphylococcus/enzimologia , Staphylococcus/metabolismo
20.
Food Microbiol ; 27(4): 447-52, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20417392

RESUMO

Staphylococcus spp. are microorganisms that are naturally present in milk and dairy products and are often associated with food-borne diseases outbreaks due to the ability of some strains to produce thermostable enterotoxins. This ability is usually associated with coagulase and thermonuclease production, characteristics that are considered in the microbiological analyses for the control of such microorganisms. The objective of this study was to evaluate the culture media and the methodologies used for the enumeration of coagulase and thermonuclease-positive Staphylococcus spp. in raw milk and fresh soft cheese. Samples of artificially contaminated milk (with coagulase-positive Staphylococcus reference strains) and samples of naturally contaminated raw milk and cheese were submitted for enumeration in Baird-Parker agar (BP), Rabbit Plasma Fibrinogen agar (RPFA) and in the Petrifilm Staph Express count system (STX). No significant differences (P > 0.05) were observed between the mean counts obtained in all of the evaluated culture media. RPFA and STX had good correlation indices between the total and typical colony counts as well as with coagulase and the thermonuclease-positive colony counts. Thus, there is a better association between coagulase and thermonuclease production to typical colony morphology developed on these culture media, leading to more accurate and reliable results than with BP, which demonstrated lower correlation indices between these counts.


Assuntos
Queijo/microbiologia , Contagem de Colônia Microbiana/métodos , Contaminação de Alimentos/análise , Leite/microbiologia , Staphylococcus/isolamento & purificação , Ágar , Animais , Técnicas Bacteriológicas , Coagulase/metabolismo , Meios de Cultura/química , Microbiologia de Alimentos , Humanos , Nuclease do Micrococo/metabolismo , Staphylococcus/enzimologia , Staphylococcus/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA