Staphylococcins are antimicrobial peptides or proteins produced by staphylococci. They can be separated into different classes, depending on their amino acid composition, structural complexity, and steps involved in their production. In... more
Staphylococcins are antimicrobial peptides or proteins produced by staphylococci. They can be separated into different classes, depending on their amino acid composition, structural complexity, and steps involved in their production. In this review, an overview of the current knowledge on staphylococcins will be presented with emphasis on the information collected in the last decade, including a brief description of new peptides. Most staphylococcins characterized to date are either lantibiotics or linear class II bacteriocins. Recently, gene clusters coding for production of circular bacteriocins, sactipeptides, and thiopeptides have been mined from the genome of staphylococcal isolates. In contrast to class II bacteriocins, lantibiotics, sactipeptides, and thiopeptides undergo post-translational modifications that can be quite extensive, depending on the peptide. Few staphylococcins inhibit only some staphylococcal species, but most of them have proven to target pathogens belonging to different genera and involved in a variety of infectious diseases of clinical or agronomic importance. Therefore, these peptides exhibit potential application as anti-infective drugs in different areas. This review will also cover this diverse and remarkable potential. To be commercialized, however, staphylococcin production should be cost-effective and result in high bacteriocin yields, which are not generally achieved from the culture supernatant of their native producers. Such low yields make their production quite costly and not suitable at large industrial scale. Efforts already made to overcome this limitation, minimizing costs and time of production of some staphylococcins and employing either chemical synthesis or in vivo biosynthesis, will be addressed in this review as well. • Staphylococci produce a variety of antimicrobial peptides known as staphylococcins. • Most staphylococcins are post-translationally modified peptides. • Staphylococcins exhibit potential biotechnological applications. Graphical abstract
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OBJECTIVES The present study reports the draft genome sequence of Staphylococcus aureus 4181, a strain involved in bovine mastitis that produces aureocin 4181, a broad-spectrum antimicrobial peptide (AMP). The inhibition of... more
OBJECTIVES The present study reports the draft genome sequence of Staphylococcus aureus 4181, a strain involved in bovine mastitis that produces aureocin 4181, a broad-spectrum antimicrobial peptide (AMP). The inhibition of multidrug-resistant (MDR) staphylococci involved in human infections by S. aureus 4181was also investigated. METHODS The sequencing library was constructed using the Nextera XT DNA library preparation Kit (Illumina). The whole-genome shotgun sequencing was obtained by using the Illumina MiSeq System. The A5-miseq pipeline was employed for de novo genome assembly. The genome annotation was performed by the RAST server. The online automated tools BAGEL4 and antiSMASH v. 5.0 were used for mining gene clusters coding for AMP production. The virulence potential of the strain was investigated employing online tools. Its inhibitory activity toward MDR staphylococcal isolates associated to human infections was tested by the deferred-antagonism assay on BHI agar medium. RESULTS The total scaffold size was determined to be 2 719 949 bp, with a G + C content of 32.7%. The genome analyses revealed 2 504 protein and 74 RNA encoding sequences, several genes coding for drug resistance and a single AMP gene cluster coding for aureocin 4181.S. aureus 4181 exhibited a pathogenic potential and inhibited all MDR staphylococcal isolates tested as target. CONCLUSIONS This study describes the main features of the draft genome ofS. aureus 4181, a strain that produces the third four-component bacteriocin described in the literature, aureocin 4181. This bacteriocin is a potential alternative drug to control MDR staphylococcal isolates involved in human infections.
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A mastite e a inflamacao da glândula mamaria causada, principalmente, pela presenca de bacterias e o genero Staphylococcus tem sido o mais isolado em casos de mastite bovina. Essa doenca pode causar alteracoes no leite, comprometendo sua... more
A mastite e a inflamacao da glândula mamaria causada, principalmente, pela presenca de bacterias e o genero Staphylococcus tem sido o mais isolado em casos de mastite bovina. Essa doenca pode causar alteracoes no leite, comprometendo sua qualidade e a dos seus derivados. A mastite gera grandes perdas economicas devido a queda da producao de leite, ao descarte do leite contaminado e, tambem, dos animais infectados. O S. aureus e um importante patogeno, classificado como contagioso. Sua caracterizacao e importante para que possam ser determinados os fenotipos e os genotipos associados aos casos de mastite bovina. O presente trabalho determinou o perfil de sensibilidade aos antimicrobianos de 15 estirpes de S. aureus isoladas de mastite subclinica bovina e avaliou a similaridade genotipica existente entre as estirpes. As bacterias foram isoladas e identificadas de acordo com o National Mastitis Council (2014). O teste de suscetibilidade aos antimicrobianos foi realizado pela tecnica de...
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In the present scenario of a major demand for new compounds with antimicrobial activity, bacteriocin and bacteriocin-like inhibitory substances (BLIS) are promising tools against deteriorating and pathogenic microorganisms, thus having... more
In the present scenario of a major demand for new compounds with antimicrobial activity, bacteriocin and bacteriocin-like inhibitory substances (BLIS) are promising tools against deteriorating and pathogenic microorganisms, thus having potential applications in both the food industry and infectious disease control. In the present report, we describe the genetic and phenotypic characteristics of BLIS produced by Enterococcus faecium E86, a strain previously isolated and sequenced by our group, focusing on the structural genes of two bacteriocins identified: enterocin TW21 and enterocin P. Transcription of all four genes associated with the biosynthesis and immunity of enterocin P and enterocin TW21 were confirmed by RT-PCR. However, Sanger sequencing confirmed a truncation of the structural gene of enterocin TW21 due to one base pair deletion (A/T). Thus, although E. faecium E86 was shown to carry two bacteriocinogenic gene clusters, only one cluster encodes a functional bacteriocin, enterocin P. Enterocin P was able to inhibit different strains of Listeria monocytogenes and vancomycin-resistant enterococci (both Enterococcus faecalis and Enterococcus faecium), showing intense bacteriolytic activity, in most cases.
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Enterococcus faecium is a frequently antibiotic-resistant opportunistic pathogen that is commonly recovered from hospitalized patients. The genetic organization of the dnaK operon was analyzed and was shown to consist of at least four... more
Enterococcus faecium is a frequently antibiotic-resistant opportunistic pathogen that is commonly recovered from hospitalized patients. The genetic organization of the dnaK operon was analyzed and was shown to consist of at least four heat shock genes, hrcA-grpE-dnaK-dnaJ. The dnaK/J intergenic region was 140 bp shorter than in E. faecalis. The dnaK operon was expressed from a putative sigma(A)-type promoter (PhrcA) upstream of the hrcA start codon and was preceded by two conserved CIRCE sequences. Northern hybridization revealed the presence of multiple mRNAs in the dnaK operon. Conversely, the groE operon was transcribed as a single mRNA. Induction of dnaK and groEL genes occurred in response to either heat shock or exposure to other stress agents.
Research Interests: Genetics, Microbiology, Medical Microbiology, Biology, Oxidative Stress, and 12 moreAntibiotic Resistance, Molecular chaperones, Stress response, Gene Order, Osmotic pressure, Enterococcus faecium, Enterococcus faecalis, Heat Shock, Heat Shock Proteins, Base Sequence, Gene Expression Regulation, and Molecular Sequence Data
This study analyzed ten strains of coagulase-negative staphylococci (CNS) involved in nosocomial infections in three Brazilian hospitals. Their antibiotic susceptibility profile showed that most strains exhibited multiple antibiotic... more
This study analyzed ten strains of coagulase-negative staphylococci (CNS) involved in nosocomial infections in three Brazilian hospitals. Their antibiotic susceptibility profile showed that most strains exhibited multiple antibiotic resistance and possessed the mecA gene. The ability of these strains to adhere to polystyrene microtiter plates was also tested and nine of them proved to be biofilm producers at least in one of the three conditions tested: growth in TSB, in TSB supplemented with NaCl, or in TSB supplemented with glucose. The presence of the bap gene, which codes for the biofilm-associated protein (Bap), was investigated in all ten strains by PCR. AU strains were bop-positive and DNA sequencing experiments confirmed that the fragments amplified were indeed part of a bap gene. The presence of the icaA gene, one of the genes involved in polysaccharide intercellular adhesin (PIA) formation, was also detected by PCR in eight of the ten strains tested. The two icaA-negative strains were either weak biofilm producer or no biofilm producer, although they were bop-positive. To our knowledge, this is the first report demonstrating the presence of the bap gene in nosocomial isolates of CNS, being also the first report on the presence of this gene in Staphylococcus haemolyticus and S. cohnii.
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Research Interests: Microbiology, Medical Microbiology, Antimicrobial Peptides, Bovine Mastitis, Bacteriocins, and 15 moreFemale, Animals, Bacteria, Staphylococcus aureus, Antimicrobial Peptide, Bacteriocin, Staphylococcus epidermidis, Cattle, Spectrum, Bacteriocin and Its Applications, Streptococci, Drug synergism, Antimicrobial agent, Genetic background, and Streptococcal infections
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Here, we transcriptionally and phenotypically characterized the clpB gene from Enterococcus faecalis. Northern blot analysis identified a monocistronic mRNA strongly induced at 48 and 50 °C. In silico analysis identified that the clpB... more
Here, we transcriptionally and phenotypically characterized the clpB gene from Enterococcus faecalis. Northern blot analysis identified a monocistronic mRNA strongly induced at 48 and 50 °C. In silico analysis identified that the clpB gene encodes a protein of 868 aa with a predicted molecular mass of approximately 98 kDa, presenting two conserved ATP-binding domains. Sequence analysis also identified a CtsR-binding box upstream of the putative −10 sequence, and inactivation of the ctsR gene resulted in an approximately 2-log increase in clpB mRNA expression, confirming ClpB as a member of the CtsR regulon. While expression of clpB was induced by heat stress, a ΔclpB strain grew relatively well under many different stressful conditions, including elevated temperatures. However, expression of ClpB appears to play a major role in induced thermotolerance and in pathogenesis, as assessed by using the Galleria mellonella virulence model.
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Research Interests: Microbiology, Medical Microbiology, Porifera, Antimicrobials, Antibiotic Resistance, and 13 morePhylogeny, Animals, Drug Resistance, Pseudomonas, Bacteria, Pseudomonas putida, Gram Positive Bacteria, Marine invertebrates, Antibiotics, Gram-negative bacteria, Anti-Bacterial Agents, Microbial Sensitivity Tests, and Oceans and Seas
Mupirocin is a topical antimicrobial agent that is used for the treatment of skin and postoperative wound infections, and the prevention of nasal carriage of meticillin-resistant Staphylococcus aureus (MRSA). However, the prevalence of... more
Mupirocin is a topical antimicrobial agent that is used for the treatment of skin and postoperative wound infections, and the prevention of nasal carriage of meticillin-resistant Staphylococcus aureus (MRSA). However, the prevalence of mupirocin resistance in S. aureus, particularly in MRSA, has increased. High-level mupirocin resistance, with MICs ≥512 μg ml−1, is mediated by the ileS-2 gene, which is located on conjugative plasmids. In the present study, we investigated whether mupirocin influences the expression of the ileS-2 gene responsible for high-level mupirocin resistance, and we present some evidence that this gene is not upregulated but constitutively expressed in S. aureus.
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Aureocin A53 is an antimicrobial peptide produced by Staphylococcus aureus A53. The genetic determinants involved in aureocin A53 production and immunity to its action are organized in at least four transcriptional units encoded by the... more
Aureocin A53 is an antimicrobial peptide produced by Staphylococcus aureus A53. The genetic determinants involved in aureocin A53 production and immunity to its action are organized in at least four transcriptional units encoded by the 10.4-kb plasmid pRJ9. One transcriptional unit carries only the bacteriocin structural gene, aucA . No immunity gene is found downstream of aucA , as part of the same transcriptional unit. Further downstream of aucA is found an operon which contains the three genes aucEFG , whose products seem to associate to form a dedicated ABC transporter. When aucEFG were expressed in RN4220, an aureocin A53-sensitive S. aureus strain, this strain became partially resistant to the bacteriocin. A gene disruption mutant in aucE was defective in aureocin A53 externalization and more sensitive to aureocin A53 than the wild-type strain, showing that aucEFG are involved in immunity to aureocin A53 by active extrusion of the bacteriocin. Full resistance to aureocin A53 w...
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One of the outstanding problems in the field of heat shock response has been to elucidate the mechanism underlying the induction of heat shock proteins (HSPs). In this work, we initiate an analysis of the expression of heat shock groEL... more
One of the outstanding problems in the field of heat shock response has been to elucidate the mechanism underlying the induction of heat shock proteins (HSPs). In this work, we initiate an analysis of the expression of heat shock groEL and dnaK genes and their promoters in S. pyogenes. The synthesis of total cellular proteins was studied upon transfer of a log-phase culture from 37 degrees C to 42 degrees C by performing 5-min pulse-labeling experiments with (35)S-Met. The heat shock responses in the pathogenic Gram-positive cocci, Enterococcus faecalis and Staphylococcus aureus, were also analyzed.
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We have characterized the heat-shock response of the nosocomial pathogen Enterococcus faecium. The growth of E. faecium cells was analyzed at different temperatures; little growth was observed at 50 degrees C, and no growth at 52 degrees... more
We have characterized the heat-shock response of the nosocomial pathogen Enterococcus faecium. The growth of E. faecium cells was analyzed at different temperatures; little growth was observed at 50 degrees C, and no growth at 52 degrees C or 55 degrees C. In agreement, a marked decrease of general protein synthesis was observed at 52 degrees C, and very light synthesis was detected at 55 degrees C. The heat resistance of E. faecium cells was analyzed by measuring the survival at temperatures higher than 52 degrees C and, after 2 h of incubation, viable cells were still observed at 70 degrees C. By Western blot analysis, two heat-induced proteins were identified as GroEL (65 kDa) and DnaK (75 kDa). Only one isoform for either GroEL or DnaK was found. The gene expression of these heat-shock proteins was also analyzed by pulsed-labeled experiments. The heat-induced proteins showed an increased rate of synthesis during the first 5 min, reaching the highest level of induction after 10 min and returning to the steady-state level after 20 min of heat treatment.
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Hyicin 3682, the first bacteriocin reported for Staphylococcus hyicus, is a BsaCOL variant produced by S. hyicus 3682, a strain isolated from bovine milk. Hyicin 3682 is found in the culture supernatant, is bactericidal and its producing... more
Hyicin 3682, the first bacteriocin reported for Staphylococcus hyicus, is a BsaCOL variant produced by S. hyicus 3682, a strain isolated from bovine milk. Hyicin 3682 is found in the culture supernatant, is bactericidal and its producing strain exhibits a much broader spectrum of antimicrobial activity than the producing strain of BsaCOL against several Gram-positive bacteria, which include foodborne pathogens, food-spoilage microorganisms and bacterial species of medical and veterinary importance. Sequencing of the genome of S. hyicus 3682 provided the nucleotide sequence of the entire gene cluster involved in hyicin 3682 production, which seems to be located on pRJ109, the single plasmid carried by this strain. This gene cluster is expressed and consists of 8525bp and of eight genes (hyiA, hyiB, hyiC, hyiD, hyiP, hyiF, hyiE and hyiG) encoded on the same DNA strand. The mature lantibiotic exhibits 91% identity to BsaCOL and its molecular mass was found to be ∼26Da higher due to two amino acid substitutions. S. hyicus 3682 proved to be only partially immune to its cognate bacteriocin up to 1024 AU/ml. Therefore, hyicin 3682, the first Bsa variant reported in coagulase-negative staphylococci, does exhibit antimicrobial and siblicidal activities.
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Abstract Reducing salt content in foods such as cheeses, while limiting the growth of spoilage microorganisms and foodborne pathogens, is a difficult challenge. One method that may prove useful is use of staphylococcins, which are... more
Abstract Reducing salt content in foods such as cheeses, while limiting the growth of spoilage microorganisms and foodborne pathogens, is a difficult challenge. One method that may prove useful is use of staphylococcins, which are bacteriocins produced by staphylococci. Therefore, staphylococcin antimicrobial activity against six strains of S. aureus isolated from cheese was tested aiming at their industrial application in biopreservation of Minas fresh (Frescal) cheese with reduced sodium content. Three staphylococcins were selected for these tests: Pep 5, aureocin A53 and lysostaphin. All three staphylococcins proved to be bacteriolytic against all six strains of S. aureus. The antimicrobial activity of the partially purified staphylococcins was subsequently investigated against strains S. aureus Q1 and QJ3 in cheese matrices (6.0 log CFU/g) with different NaCl contents (control, a 25% reduction, and a 50% reduction), kept under refrigeration at 4 °C, for 21 days. Both strains were shown to be of concern for food industry as they carry the SEA, SEB and SEH enterotoxin genes, and are resistant to β-lactam drugs and moderate biofilm formers when grown in TSB. When used singly, Pep5, aureocin A53 and lysostaphin reduced approximately 95%, 99% and 99.99% of the viable cell counts, respectively, irrespective of the sodium content of the cheese matrix. The combined action of aureocin A53 and Pep5 resulted in an additional and significant reduction (p 0.05) than that observed when lysostaphin was employed singly. Lysostaphin also proved to reduce the number of the staphylococcal viable cells to a level (~ 2.0 log CFU/g) at which enterotoxin production should not reach a sufficient quantity to cause food poisoning. Therefore, lysostaphin may have a practical application in the food industry to control staphylococcal contamination of Minas fresh cheese with a sodium content reduced up to 50%, providing consumers with more safe options to reduce their intake of sodium.
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OBJECTIVES The aim of this study was to report the draft genome sequence of the bacteriocinogenic strain Enterococcus faecium E86. Bacteriocins are prokaryotic peptides or proteins with antimicrobial activity. The genome information may... more
OBJECTIVES The aim of this study was to report the draft genome sequence of the bacteriocinogenic strain Enterococcus faecium E86. Bacteriocins are prokaryotic peptides or proteins with antimicrobial activity. The genome information may contribute to the identification of enterocins produced by this strain that exhibit inhibitory activity against the foodborne pathogen Listeria monocytogenes and vancomycin-resistant enterococci (VRE) involved in human infections, among other bacterial genera and species. METHODS An Illumina MiSeq platform was used for genome sequencing. De novo assembly of 5 735 838 paired-end reads was done using the A5-miseq pipeline, yielding >300-fold average genome coverage. Genome annotation was performed by the RAST server, and mining of the bacteriocinogenic gene clusters was done using the BAGEL3 and antiSMASH v.4 platforms. RESULTS The total scaffold size was determined to be 2 689 107 bp, approximately 2.7 Mbp, featuring a G + C content of 38.1%. The genome contains 2858 coding sequences and 74 RNA genes. Genome analyses revealed the presence of: 30 genes involved in drug resistance; 2 bacteriocinogenic gene clusters (for enterocin P and enterocin TW21); EntiTW21, a novel bacteriocin immunity protein and a novel multilocus sequence type (ST1500). CONCLUSION This work highlights the potential biotechnological application of this strain for the production of enterocin P, a bacteriocin that can be employed in the food industry as a biopreservative against L. monocytogenes and as an alternative to classical antibiotics against VRE.
Research Interests: Medicine()
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One of the biggest challenges faced presently by clinicians is the emergence of multi drug--resistant pathogens that can infect humans and animals.To control the infections caused by such pathogens the development of new drugs is... more
One of the biggest challenges faced presently by clinicians is the emergence of multi drug--resistant pathogens that can infect humans and animals.To control the infections caused by such pathogens the development of new drugs is required. Bacteria are a rich source of ribosomally-synthesized antimicrobial peptides known as bacteriocins, which are characterized by the presence of a self-defense immunity system. Labionin-containing lantibiotics and sactibiotics are post-translationally modified bacteriocins with peculiar features. Labionin-containing peptides belong tosubclass Iclantibiotics in which the carbacyclic triamino triacid labionin, a structural variant of lanthionine,and a methyl-substitute labionin derivative are found, giving the molecule a labyrinthine structure. Sactibiotics are circular or linear peptides belonging to a distinct bacteriocin class (class V) which is characterized by the presence of cross-linkages formed by the thiol group of cysteine residues and the α...
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The phylum Actinobacteria, which comprises a great variety of Gram-positive bacteria with a high G+C content in their genomes, is known for its large production of bioactive compounds, including those with antimicrobial activity. Among... more
The phylum Actinobacteria, which comprises a great variety of Gram-positive bacteria with a high G+C content in their genomes, is known for its large production of bioactive compounds, including those with antimicrobial activity. Among the antimicrobials, bacteriocins, ribosomally-synthesized peptides, represent an important arsenal of potential new drugs to face the increasing prevalence of resistance to antibiotics among microbial pathogens. The actinobacterial bacteriocins form a heterogeneous group of substances that is difficult to adapt to most proposed classification schemes. However, recent updates have accommodated efficiently the diversity of bacteriocins produced by this phylum. Among the bacteriocins, the lantibiotics represent a source of new antimicrobials to control infections caused mainly by Gram-positive bacteria and with a low propensity for resistance development. Moreover, some of these compounds have additional biological properties, exhibiting activity against...
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Research Interests: Bacteriology, Kinetics, Biology, Membrane Proteins, Medicine, and 14 moreBiological Sciences, Mutagenesis, Microbial genetic and drug resistance, Temperature, Plasmids, Phenotype, Molecular cloning, Enterococcus faecalis, Amino Acid Sequence, Base Sequence, Cytotoxins, Temperature Sensitive Polymer, Molecular Sequence Data, and Medical and Health Sciences
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Research Interests: Thai()
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Hyicin 4244 is a small antimicrobial peptide with a broad-spectrum of activity found in the culture supernatant of Staphylococcus hyicus 4244, whose genome was then sequenced. The bacteriocin gene cluster (hyiSABCDEFG) was mined from its... more
Hyicin 4244 is a small antimicrobial peptide with a broad-spectrum of activity found in the culture supernatant of Staphylococcus hyicus 4244, whose genome 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 reduced significantly the number of CFU and the biofilm formation by two strong biofilm-forming strains randomly chosen as representatives of the st...
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Research Interests: Genetics, Microbiology, Epidemiology, Genomics, Medical Microbiology, and 15 moreBovine Mastitis, Genetic Diversity, Phylogeny, Bacteriocins, Listeria monocytogenes, Bacteria, Staphylococcus aureus, Polymerase Chain Reaction, DNA fingerprinting, Plasmids, Antimicrobial Peptide, Bacteriocin, Genotype, Strain, and gene amplification
Coagulase-negative staphylococci are thought to act as reservoirs of antibiotic resistance genes that can be transferred to Staphylococcus aureus, thus hindering the combat of this bacterium. In this work we analyzed the presence of... more
Coagulase-negative staphylococci are thought to act as reservoirs of antibiotic resistance genes that can be transferred to Staphylococcus aureus, thus hindering the combat of this bacterium. In this work we analyzed the presence of plasmids conferring resistance to the antibiotic mupirocin - widely used to treat and prevent S. aureus infections in hospital environments - in nosocomial Staphylococcus haemolyticus strains. About 12% of the 75 strains tested were resistant to mupirocin, and this phenotype was correlated with the presence of plasmids. These plasmids were shown to be diverse, being either conjugative or mobilizable, and capable of transferring mupirocin resistance to S. aureus Our findings reinforce that S. haemolyticus, historically and mistakenly considered as a less important pathogen, is a reservoir of resistance genes which can be transferred to other bacteria, such as S. aureus, emphasizing the necessity of more effective strategies to detect and combat this emerg...
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Aureocin A70 is the only four-component bacteriocin described to date. As it inhibits the growth of a wide range of Gram-positive bacteria, including Listeria monocytogenes strains isolated from food, its potential for improving food... more
Aureocin A70 is the only four-component bacteriocin described to date. As it inhibits the growth of a wide range of Gram-positive bacteria, including Listeria monocytogenes strains isolated from food, its potential for improving food safety was investigated in this study. Aureocin A70 (10,240AU/mL) proved to be bactericidal, but not extensively lytic, against listerial strains. The antibacterial activity of aureocin A70 (16AU/mL) was then tested in UHT-treated skimmed milk inoculated with the food-associated L. monocytogenes L12 strain (4-log CFU/mL) during storage at 4°C for one week. Aureocin A70 caused a time-dependent reduction in the listerial viable cell counts (5.51-log units) up to 7days of incubation. Aureocin A70 was neither toxic to the Vero and the L-929 cell lines nor exhibited a hemolytic activity against sheep red blood cells. Aureocin A70 proved to be completely stable for one month at 25°C, 16weeks at 4°C and 20weeks at -20°C. Aureocin A70 exhibited a time-dependent susceptibility to simulated gastric juice and bile salts mimicking gastrointestinal conditions. The entrapment of aureocin A70 in an alginate/gelatin matrix revealed that this bacteriocin can be released from this matrix. Moreover, it remained adsorbed to and active on a low-density polyethylene plastic surface suggesting that aureocin A70 may be employed in bioactive packaging to control the growth of undesirable bacteria. Taken together these results suggest that aureocin A70 is a promising alternative to be used in food applications.
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Staphylococcus aureus A70 produces a heat-stable bacteriocin designated aureocin A70. Aureocin A70 is encoded within a mobilisable 8 kb plasmid, pRJ6, and is active against Listeria monocytogenes. Experiments of transposition mutagenesis... more
Staphylococcus aureus A70 produces a heat-stable bacteriocin designated aureocin A70. Aureocin A70 is encoded within a mobilisable 8 kb plasmid, pRJ6, and is active against Listeria monocytogenes. Experiments of transposition mutagenesis and gene cloning had shown that aureocin A70 production and immunity were associated with the HindIII-A and B fragments of pRJ6. Therefore, a 6332 bp region of the plasmid, encompassing both these fragments, was sequenced using a concatenation DNA sequencing procedure. DNA sequence and genetic analyses revealed the presence of three transcriptional units that appear to be involved in bacteriocin activity. The first transcriptional unit contains a single gene, aurT, which encodes a protein that resembles an ATP-dependent transporter, similar to those involved in lantibiotic export. AurT is required for aureocin A70 production and it appears to be essential for mobilisation of pRJ6. The second putative operon contains two open reading frames (ORFs); the first gene, orfA, is predicted to encode a protein similar to small repressor proteins found in some Archaea, whose function remains to be elucidated. The second gene, orfB, codes for an 138 amino acid residue protein which shares a number of characteristics (high pI and hydrophobicity profile) with proteins associated with immunity, needed for self-protection against bacteriocin. Four other genes are present in the third operon, aurABCD. aurABCD encode four related peptides that are small (30-31 amino acid residues), strongly cationic (pI of 9.85 to 10.04) and highly hydrophobic. Theses peptides also have a high content of small amino acid residues like glycine and alanine, and no cysteine residue. Tn917-lac insertional mutations, which affected aureocin A70 activity, reside within operon aurABCD. Analysis of purified bacteriocin preparations by mass spectrometry demonstrated that all four peptides encoded by aurABCD operon are produced, expressed and excreted without post-translational modifications. Thus, aureocin A70 is a multi-peptide non-lantibiotic bacteriocin, which is transported without processing.
Research Interests: Genetics, Molecular Biology, Mass Spectrometry, Molecular, Maldi Tof, and 18 moreGene Cloning, Sequence alignment, Bacteriocins, Time of Flight, Staphylococcus aureus, Peptides, Plasmids, Phenotype, High Pressure Liquid Chromatography, Amino Acid Sequence, Base Sequence, Open Reading Frame, Chlortetracycline, Biochemistry and cell biology, Sulfamethazine, DNA sequence, Penicillin G, and Molecular Sequence Data(Gene Cloning, Sequence alignment, Bacteriocins, Time of Flight, Staphylococcus aureus, Peptides, Plasmids, Phenotype, High Pressure Liquid Chromatography, Amino Acid Sequence, Base Sequence, Open Reading Frame, Chlortetracycline, Biochemistry and cell biology, Sulfamethazine, DNA sequence, Penicillin G, and Molecular Sequence Data)
(Gene Cloning, Sequence alignment, Bacteriocins, Time of Flight, Staphylococcus aureus, Peptides, Plasmids, Phenotype, High Pressure Liquid Chromatography, Amino Acid Sequence, Base Sequence, Open Reading Frame, Chlortetracycline, Biochemistry and cell biology, Sulfamethazine, DNA sequence, Penicillin G, and Molecular Sequence Data)
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Staphylococcus aureus A70 produces a heat-stable bacteriocin designated aureocin A70. Aureocin A70 is encoded within a mobilisable 8 kb plasmid, pRJ6, and is active against Listeria monocytogenes. Experiments of transposition mutagenesis... more
Staphylococcus aureus A70 produces a heat-stable bacteriocin designated aureocin A70. Aureocin A70 is encoded within a mobilisable 8 kb plasmid, pRJ6, and is active against Listeria monocytogenes. Experiments of transposition mutagenesis and gene cloning had shown that aureocin A70 production and immunity were associated with the HindIII-A and B fragments of pRJ6. Therefore, a 6332 bp region of the plasmid, encompassing both these fragments, was sequenced using a concatenation DNA sequencing procedure. DNA sequence and genetic analyses revealed the presence of three transcriptional units that appear to be involved in bacteriocin activity. The first transcriptional unit contains a single gene, aurT, which encodes a protein that resembles an ATP-dependent transporter, similar to those involved in lantibiotic export. AurT is required for aureocin A70 production and it appears to be essential for mobilisation of pRJ6. The second putative operon contains two open reading frames (ORFs); the first gene, orfA, is predicted to encode a protein similar to small repressor proteins found in some Archaea, whose function remains to be elucidated. The second gene, orfB, codes for an 138 amino acid residue protein which shares a number of characteristics (high pI and hydrophobicity profile) with proteins associated with immunity, needed for self-protection against bacteriocin. Four other genes are present in the third operon, aurABCD. aurABCD encode four related peptides that are small (30–31 amino acid residues), strongly cationic (pI of 9.85 to 10.04) and highly hydrophobic. Theses peptides also have a high content of small amino acid residues like glycine and alanine, and no cysteine residue. Tn917-lac insertional mutations, which affected aureocin A70 activity, reside within operon aurABCD. Analysis of purified bacteriocin preparations by mass spectrometry demonstrated that all four peptides encoded by aurABCD operon are produced, expressed and excreted without post-translational modifications. Thus, aureocin A70 is a multi-peptide non-lantibiotic bacteriocin, which is transported without processing.
Research Interests: Genetics, Molecular Biology, Mass Spectrometry, Gene Cloning, Sequence alignment, and 16 moreBacteriocins, Time of Flight, Staphylococcus aureus, Peptides, Plasmids, Phenotype, High Pressure Liquid Chromatography, Amino Acid Sequence, Base Sequence, Open Reading Frame, Chlortetracycline, Biochemistry and cell biology, Sulfamethazine, DNA sequence, Penicillin G, and Molecular Sequence Data(Bacteriocins, Time of Flight, Staphylococcus aureus, Peptides, Plasmids, Phenotype, High Pressure Liquid Chromatography, Amino Acid Sequence, Base Sequence, Open Reading Frame, Chlortetracycline, Biochemistry and cell biology, Sulfamethazine, DNA sequence, Penicillin G, and Molecular Sequence Data)
(Bacteriocins, Time of Flight, Staphylococcus aureus, Peptides, Plasmids, Phenotype, High Pressure Liquid Chromatography, Amino Acid Sequence, Base Sequence, Open Reading Frame, Chlortetracycline, Biochemistry and cell biology, Sulfamethazine, DNA sequence, Penicillin G, and Molecular Sequence Data)
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To investigate the activity of seven staphylococcins, bacteriocins produced by staphylococci, against multiresistant Staphylococcus aureus and coagulase-negative staphylococci (CNS) involved in human infections. Four bacteriocins produced... more
To investigate the activity of seven staphylococcins, bacteriocins produced by staphylococci, against multiresistant Staphylococcus aureus and coagulase-negative staphylococci (CNS) involved in human infections. Four bacteriocins produced by Staph. epidermidis (Pep5, epidermin, epilancin K7 and epicidin 280) and three produced by Staph. aureus (aureocins A70, A53 and 215FN) were tested. Sixteen Staph. aureus strains, including a representative strain of the endemic Brazilian methicillin-resistant clone (MRSA), and 57 CNS strains were used as indicators. Among the staphylococcins used, Pep5 was able to inhibit 77.2% of the CNS strains and 87.5% of the Staph. aureus strains tested, including the Brazilian MRSA endemic clone, responsible for a large number of hospital-acquired infections in Brazil. On the other hand, aureocin A53 and epidermin presented a high antagonistic activity only against the Staph. aureus strains, being able to inhibit, respectively, 87.5% and 81.3% of them, inc...
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Plasmids specifying bacteriocin production and immunity to its action were found in three clinical isolates of Staphylococcus aureus obtained in different hospitals located in Rio de Janeiro. These plasmids (pRJ28, pRJ29 and pRJ30) of 8.0... more
Plasmids specifying bacteriocin production and immunity to its action were found in three clinical isolates of Staphylococcus aureus obtained in different hospitals located in Rio de Janeiro. These plasmids (pRJ28, pRJ29 and pRJ30) of 8.0 kb were found to generate identical restriction fragment patterns upon digestion with several enzymes, although the range of strains susceptible to the respective bacteriocin varied among the producer strains, when different Gram-positive bacteria were used as indicators, pRJ29 was then chosen for further characterization in order to compare it with pRJ6 and pRJ9, two small bacteriocin-encoding plasmids previously described in strains isolated from food. pRJ29 was found to code for a bacteriocin with chemical properties (sensitivity to proteases, heat resistance, activity under anaerobiosis, and estimated molecular weight) similar to those of pRJ6-encoded bacteriocin, conferring cross-immunity to it. However, its restriction map differed from those...
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Bacteriocins are prokaryotic proteins or peptides with antimicrobial activity. Most of them exhibit a broad spectrum of activity, inhibiting micro-organisms belonging to different genera and species, including many bacterial pathogens... more
Bacteriocins are prokaryotic proteins or peptides with antimicrobial activity. Most of them exhibit a broad spectrum of activity, inhibiting micro-organisms belonging to different genera and species, including many bacterial pathogens which cause human, animal or plant infections. Therefore, these substances have potential biotechnological applications in either food preservation or prevention and control of bacterial infectious diseases. However, there is concern that continuous exposure of bacteria to bacteriocins may select cells resistant to them, as observed for conventional antimicrobials. Based on the models already investigated, bacteriocin resistance may be either innate or acquired and seems to be a complex phenomenon, arising at different frequencies (generally from 10-9 to 10-2) and by different mechanisms, even among strains of the same bacterial species. In the present review, we will discuss the prevalence, development, and molecular mechanisms involved in resistance ...
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Enterococcus faecium is a frequently antibiotic-resistant opportunistic pathogen that is commonly recovered from hospitalized patients. The genetic organization of the dnaK operon was analyzed and was shown to consist of at least four... more
Enterococcus faecium is a frequently antibiotic-resistant opportunistic pathogen that is commonly recovered from hospitalized patients. The genetic organization of the dnaK operon was analyzed and was shown to consist of at least four heat shock genes, hrcA-grpE-dnaK-dnaJ. The dnaK/J intergenic region was 140 bp shorter than in E. faecalis. The dnaK operon was expressed from a putative sigma(A)-type promoter (PhrcA) upstream of the hrcA start codon and was preceded by two conserved CIRCE sequences. Northern hybridization revealed the presence of multiple mRNAs in the dnaK operon. Conversely, the groE operon was transcribed as a single mRNA. Induction of dnaK and groEL genes occurred in response to either heat shock or exposure to other stress agents.
Research Interests: Genetics, Microbiology, Medical Microbiology, Oxidative Stress, Antibiotic Resistance, and 12 moreMolecular chaperones, Stress response, Gene Order, Osmotic pressure, Enterococcus faecium, Enterococcus faecalis, Heat Shock, Heat Shock Proteins, Base Sequence, *Hot Temperature, Gene Expression Regulation, and Molecular Sequence Data
Research Interests: Genetics, Microbiology, Veterinary Microbiology, Argentina, Bovine Mastitis, and 15 moreVeterinary, Phylogeny, Bacteriocins, Female, Animals, Staphylococcus aureus, Plasmids, Phenotype, Bacteriocin, Milk, Cattle, Genomic DNA, Genotyping, Pulsed field gel electrophoresis (PFGE), and Veterinary Sciences
Research Interests: Genetics, Microbiology, Medical Microbiology, Sequence alignment, Bacteriocins, and 12 moreStaphylococcus aureus, Conjugation, The, Plasmids, Mobilization, Bacteriocin, Staphylococcus epidermidis, Amino Acid Sequence, Base Sequence, Binding Site, Coagulase Negative Staphylococci, and Molecular Sequence Data
Research Interests:
Research Interests: Microbiology, Medical Microbiology, Brazil, Bovine Mastitis, Veterinary, and 20 moreBacteriocins, Animals, Nucleic acid hybridization, Listeria monocytogenes, Bacteria, Staphylococcus aureus, DNA hybridization, Plasmids, Antimicrobial Peptide, Bacteriocin, Cattle, Fermentation, Acetoin, Anti-Bacterial Agents, Microbial Sensitivity Tests, Bacillus Cereus, Coagulase, Rabbits, Plasmid DNA, and Mannitol(Bacteriocins, Animals, Nucleic acid hybridization, Listeria monocytogenes, Bacteria, Staphylococcus aureus, DNA hybridization, Plasmids, Antimicrobial Peptide, Bacteriocin, Cattle, Fermentation, Acetoin, Anti-Bacterial Agents, Microbial Sensitivity Tests, Bacillus Cereus, Coagulase, Rabbits, Plasmid DNA, and Mannitol)
(Bacteriocins, Animals, Nucleic acid hybridization, Listeria monocytogenes, Bacteria, Staphylococcus aureus, DNA hybridization, Plasmids, Antimicrobial Peptide, Bacteriocin, Cattle, Fermentation, Acetoin, Anti-Bacterial Agents, Microbial Sensitivity Tests, Bacillus Cereus, Coagulase, Rabbits, Plasmid DNA, and Mannitol)