The Experts below are selected from a list of 2547 Experts worldwide ranked by ideXlab platform
Gavin K Paterson - One of the best experts on this subject based on the ideXlab platform.
-
Staphylococcus pseudoXylosus sp nov isolated from bovine mastitis
International Journal of Systematic and Evolutionary Microbiology, 2019Co-Authors: Alison Macfadyen, Sabine Leroy, Ewan M Harrison, Julian Parkhill, Mark A Holmes, Gavin K PatersonAbstract:Strain S04009T, a Gram-stain-positive, coagulase-negative Staphylococcus, was isolated from bovine mastitis in France. 16S rRNA gene analysis revealed it to be closely related to the coagulase-negative species Staphylococcus Xylosus , Staphylococcus saprophyticus , Staphylococcus caeli and Staphylococcus edaphicus . At the whole-genome level, strain S04009T had an average nucleotide identity value <95 % and an inferred DNA–DNA hybridization value <70 % when compared to these species. Furthermore, phenotypic characteristics distinguished S04009T from those species. From these related species only strain S04009T and S. Xylosus are able to ferment xylose and these two can be distinguished by the inability of strain S04009T to express urease activity. Based on the genotypic and phenotypic results, it is proposed that this isolate is a novel species, with the name Staphylococcus pseudoXylosus sp. nov. The type strain is S04009T (=DSM 107950T=CCUG 72763T=NCTC 14184T).
-
Staphylococcus caeli sp nov isolated from air sampling in an industrial rabbit holding
International Journal of Systematic and Evolutionary Microbiology, 2019Co-Authors: Alison Macfadyen, Ewan M Harrison, Julian Parkhill, Mark A Holmes, Ilenia Drigo, Gavin K PatersonAbstract:Strain 82T, a Gram-stain-positive, coagulase-negative Staphylococcus was isolated from an air sample obtained from an industrial rabbit holding in Italy. It is phylogenetically closely related to the coagulase-negative species Staphylococcus saprophyticus , Staphylococcus Xylosus and Staphylococcus edaphicus . However, it could be distinguished from these species by sequence differences between the 16S rRNA, hsp60, rpoB, dnaJ and gap genes. At the whole genome level, the isolate had an average nucleotide identity of <95 % and an inferred DNA–DNA hybridization of <70 % when compared to these species. Based on the genotypic results, it is proposed that this isolate is a novel species, with the name Staphylococcus caeli sp. nov. The type strain is 82BT (=NCTC 14063T=CCUG 71912T).
-
A Staphylococcus Xylosus Isolate with a New mecC Allotype
Antimicrobial Agents and Chemotherapy, 2013Co-Authors: Ewan M Harrison, Vincent Perreten, Sabine Leroy, Gavin K Paterson, Matthew T. G. Holden, Fiona J. E. Morgan, Anders Rhod Larsen, Andreas Petersen, Sarne De Vliegher, Lawrence K. FoxAbstract:Recently, a novel variant of mecA known as mecC (mecA(LGA251)) was identified in Staphylococcus aureus isolates from both humans and animals. In this study, we identified a Staphylococcus Xylosus isolate that harbors a new allotype of the mecC gene, mecC1. Whole-genome sequencing revealed that mecC1 forms part of a class E mec complex (mecI-mecR1-mecC1-blaZ) located at the orfX locus as part of a likely staphylococcal cassette chromosome mec element (SCCmec) remnant, which also contains a number of other genes present on the type XI SCCmec.
Régine Talòn - One of the best experts on this subject based on the ideXlab platform.
-
Transcriptomic Analysis of Staphylococcus Xylosus in Solid Dairy Matrix Reveals an Aerobic Lifestyle Adapted to Rind
Microorganisms, 2020Co-Authors: Sabine Leroy, Sergine Even, Pierre Micheau, Anne De La Foye, Valérie Laroute, Yves Le Loir, Régine TalònAbstract:Staphylococcus Xylosus is found in the microbiota of traditional cheeses, particularly in the rind of soft smeared cheeses. Despite its frequency, the molecular mechanisms allowing the growth and adaptation of S. Xylosus in dairy products are still poorly understood. A transcriptomic approach was used to determine how the gene expression profile is modified during the fermentation step in a solid dairy matrix. S. Xylosus developed an aerobic metabolism perfectly suited to the cheese rind. It overexpressed genes involved in the aerobic catabolism of two carbon sources in the dairy matrix, lactose and citrate. Interestingly, S. Xylosus must cope with nutritional shortage such as amino acids, peptides, and nucleotides, consequently, an extensive up-regulation of genes involved in their biosynthesis was observed. As expected, the gene sigB was overexpressed in relation with general stress and entry into the stationary phase and several genes under its regulation, such as those involved in transport of anions, cations and in pigmentation were up-regulated. Up-regulation of genes encoding antioxidant enzymes and glycine betaine transport and synthesis systems showed that S. Xylosus has to cope with oxidative and osmotic stresses. S. Xylosus expressed an original system potentially involved in iron acquisition from lactoferrin.
-
Interaction in dual species biofilms between Staphylococcus Xylosus and Staphylococcus aureus
International Journal of Food Microbiology, 2020Co-Authors: Sabine Leroy, Isabelle Lebert, Carine Andant, Régine TalònAbstract:Staphylococcus Xylosus, a coagulase-negative Staphylococcus, is frequently isolated from food products of animal origin and used as a starter culture in these products in which it contributes to their flavour, while Staphylococcus aureus, a coagulase-positive bacterium, causes foodborne intoxication and is implicated in a broad diversity of infections in medical sector, notably in nosocomial infections. S. Xylosus and S. aureus are both capable of forming a biofilm and share the same ecological niches, thus we explored their interaction in biofilms with a view to limiting the risks associated with S. aureus. Cell-free supernatants of different strains of S. Xylosus were able to inhibit the biofilm formation of S. aureus. The S. Xylosus C2a strain released into the supernatant a molecule of molecular weight above 30kDa that is resistant to proteolytic enzymes and inhibits the formation of S. aureus MW2 biofilm, though the mechanism involved has yet to be elucidated. Furthermore, S. Xylosus C2a modified the architecture of S. aureus MW2 in co-culture biofilm. Confocal laser scanning microscopy revealed that S. aureus formed a biofilm with a flat and compact structure while in co-culture with S. Xylosus the two species formed large juxtaposed aggregates throughout the period of incubation. This architecture made the S. aureus biofilm more susceptible to detachment.
-
Tetracycline Gene Transfer in Staphylococcus Xylosus in situ During Sausage Fermentation
Frontiers in Microbiology, 2019Co-Authors: Sabine Leroy, Souad Christieans, Régine TalònAbstract:The presence of determinants of resistance to antibiotics can constitute a possible safety hazard in coagulase-negative staphylococci (CNS), which are widely present in food of animal origin. Among CNS, S. Xylosus is a species frequently isolated from fermented meat products. Resistance to tetracycline was found to be one of the most distributed resistances occurring in S. Xylosus strains isolated from fermented sausages. We evaluated the transfer of tetracycline resistance in vitro and in situ between S. Xylosus strains. We selected three strains isolated from dry fermented sausages, resistant to tetracycline but not to minocycline, their resistance occurring by a mechanism of active efflux encoded by the tetK gene. Only one strain was able to transfer its tetracycline resistance to a recipient strain initially susceptible and plasmid-free using a filter mating procedure. Transfer of tetracycline resistance was observed at very low frequencies of 3.4 × 10-9 per recipient. To further investigate the transferability of this tetracycline resistance, the donor and recipient strains were tested in pilot-scale fermented sausage production. This transfer was possible but at a low rate, 1.4 × 10-7, and only under conditions of a high inoculation level of 108 CFU/g of meat. The tetK gene is located on a small mobilizable plasmid close to Staphylococcus aureus pT181 plasmid. In conclusion, the transfer of tetracycline resistance between strains of S. Xylosus is possible, but at a really low frequency in vitro and in situ in fermented sausages. Even if this represents a very moderate risk, it should be taken into account as required by the European approach of Qualified Presumption of Safety (QPS) and AFSSA safety recommendations, advising that strains used as starter cultures should not carry any transferable antibiotic resistance.
-
Evidence for nitric oxide synthase activity in Staphylococcus Xylosus mediating nitrosoheme formation
Frontiers in Microbiology, 2017Co-Authors: Geoffrey Ras, Véronique Zuliani, Patrick Derkx, Tim M Seibert, Sabine Leroy, Régine TalònAbstract:Staphylococcus Xylosus is used as a starter culture in fermented meat products and contributes to color formation by the reduction of nitrate to nitrite. Nitrite is a food additive that is chemically turned to nitric oxide (NO) in meat but its safety has been questioned. The objective of this study was to determine the ability of NO synthase (NOS) of S. Xylosus C2a to produce NO. For this purpose, a nos deletion mutant (Δnos) in S. Xylosus was constructed and NO production was evaluated in a test based on its ability to form nitrosomyoglobin and nitrosoheme. Production of NO was abrogated in the Δnos mutant under aerobic conditions and reduced about 35-40% comparing to the wild type C2a under limited oxygenation. This mutant was sensitive to oxidative stress. The expression of genes encoding catalase was modulated in the mutant with an up-regulation of katA and a down-regulation of katB and katC. The Δnos mutant displayed high colony pigmentation after prolonged growth on agar medium. Finally, the Δnos mutant showed no growth in minimal medium. Growth was not restored in the minimal medium by complementation with nos, but was restored by either addition of phenylalanine or complementation with pdt, a gene that encodes a prephenate dehydratase involved in phenylalanine biosynthesis and co-transcribed with nos. Our findings clearly demonstrate NOS-mediated NO production in S. Xylosus, a meat-associated coagulase-negative Staphylococcus.
-
Insight into the genome of Staphylococcus Xylosus, a ubiquitous species well adapted to meat products
Microorganisms, 2017Co-Authors: Sabine Leroy, Aurore Vermassen, Régine TalònAbstract:Staphylococcus Xylosus belongs to the vast group of coagulase-negative staphylococci. It is frequently isolated from meat products, either fermented or salted and dried, and is commonly used as starter cultures in sausage manufacturing. Analysis of the S. Xylosus genome together with expression in situ in a meat model revealed that this bacterium is well adapted to meat substrates, being able to use diverse substrates as sources of carbon and energy and different sources of nitrogen. It is well-equipped with genes involved in osmotic, oxidative/nitrosative, and acidic stress responses. It is responsible for the development of the typical colour of cured meat products via its nitrate reductase activity. It contributes to sensorial properties, mainly by the the catabolism of pyruvate and amino acids resulting in odorous compounds and by the limiting of the oxidation of fatty acids, thereby avoiding rancidity.
Sabine Leroy - One of the best experts on this subject based on the ideXlab platform.
-
Transcriptomic Analysis of Staphylococcus Xylosus in Solid Dairy Matrix Reveals an Aerobic Lifestyle Adapted to Rind
Microorganisms, 2020Co-Authors: Sabine Leroy, Sergine Even, Pierre Micheau, Anne De La Foye, Valérie Laroute, Yves Le Loir, Régine TalònAbstract:Staphylococcus Xylosus is found in the microbiota of traditional cheeses, particularly in the rind of soft smeared cheeses. Despite its frequency, the molecular mechanisms allowing the growth and adaptation of S. Xylosus in dairy products are still poorly understood. A transcriptomic approach was used to determine how the gene expression profile is modified during the fermentation step in a solid dairy matrix. S. Xylosus developed an aerobic metabolism perfectly suited to the cheese rind. It overexpressed genes involved in the aerobic catabolism of two carbon sources in the dairy matrix, lactose and citrate. Interestingly, S. Xylosus must cope with nutritional shortage such as amino acids, peptides, and nucleotides, consequently, an extensive up-regulation of genes involved in their biosynthesis was observed. As expected, the gene sigB was overexpressed in relation with general stress and entry into the stationary phase and several genes under its regulation, such as those involved in transport of anions, cations and in pigmentation were up-regulated. Up-regulation of genes encoding antioxidant enzymes and glycine betaine transport and synthesis systems showed that S. Xylosus has to cope with oxidative and osmotic stresses. S. Xylosus expressed an original system potentially involved in iron acquisition from lactoferrin.
-
Interaction in dual species biofilms between Staphylococcus Xylosus and Staphylococcus aureus
International Journal of Food Microbiology, 2020Co-Authors: Sabine Leroy, Isabelle Lebert, Carine Andant, Régine TalònAbstract:Staphylococcus Xylosus, a coagulase-negative Staphylococcus, is frequently isolated from food products of animal origin and used as a starter culture in these products in which it contributes to their flavour, while Staphylococcus aureus, a coagulase-positive bacterium, causes foodborne intoxication and is implicated in a broad diversity of infections in medical sector, notably in nosocomial infections. S. Xylosus and S. aureus are both capable of forming a biofilm and share the same ecological niches, thus we explored their interaction in biofilms with a view to limiting the risks associated with S. aureus. Cell-free supernatants of different strains of S. Xylosus were able to inhibit the biofilm formation of S. aureus. The S. Xylosus C2a strain released into the supernatant a molecule of molecular weight above 30kDa that is resistant to proteolytic enzymes and inhibits the formation of S. aureus MW2 biofilm, though the mechanism involved has yet to be elucidated. Furthermore, S. Xylosus C2a modified the architecture of S. aureus MW2 in co-culture biofilm. Confocal laser scanning microscopy revealed that S. aureus formed a biofilm with a flat and compact structure while in co-culture with S. Xylosus the two species formed large juxtaposed aggregates throughout the period of incubation. This architecture made the S. aureus biofilm more susceptible to detachment.
-
Staphylococcus pseudoXylosus sp nov isolated from bovine mastitis
International Journal of Systematic and Evolutionary Microbiology, 2019Co-Authors: Alison Macfadyen, Sabine Leroy, Ewan M Harrison, Julian Parkhill, Mark A Holmes, Gavin K PatersonAbstract:Strain S04009T, a Gram-stain-positive, coagulase-negative Staphylococcus, was isolated from bovine mastitis in France. 16S rRNA gene analysis revealed it to be closely related to the coagulase-negative species Staphylococcus Xylosus , Staphylococcus saprophyticus , Staphylococcus caeli and Staphylococcus edaphicus . At the whole-genome level, strain S04009T had an average nucleotide identity value <95 % and an inferred DNA–DNA hybridization value <70 % when compared to these species. Furthermore, phenotypic characteristics distinguished S04009T from those species. From these related species only strain S04009T and S. Xylosus are able to ferment xylose and these two can be distinguished by the inability of strain S04009T to express urease activity. Based on the genotypic and phenotypic results, it is proposed that this isolate is a novel species, with the name Staphylococcus pseudoXylosus sp. nov. The type strain is S04009T (=DSM 107950T=CCUG 72763T=NCTC 14184T).
-
Tetracycline Gene Transfer in Staphylococcus Xylosus in situ During Sausage Fermentation
Frontiers in Microbiology, 2019Co-Authors: Sabine Leroy, Souad Christieans, Régine TalònAbstract:The presence of determinants of resistance to antibiotics can constitute a possible safety hazard in coagulase-negative staphylococci (CNS), which are widely present in food of animal origin. Among CNS, S. Xylosus is a species frequently isolated from fermented meat products. Resistance to tetracycline was found to be one of the most distributed resistances occurring in S. Xylosus strains isolated from fermented sausages. We evaluated the transfer of tetracycline resistance in vitro and in situ between S. Xylosus strains. We selected three strains isolated from dry fermented sausages, resistant to tetracycline but not to minocycline, their resistance occurring by a mechanism of active efflux encoded by the tetK gene. Only one strain was able to transfer its tetracycline resistance to a recipient strain initially susceptible and plasmid-free using a filter mating procedure. Transfer of tetracycline resistance was observed at very low frequencies of 3.4 × 10-9 per recipient. To further investigate the transferability of this tetracycline resistance, the donor and recipient strains were tested in pilot-scale fermented sausage production. This transfer was possible but at a low rate, 1.4 × 10-7, and only under conditions of a high inoculation level of 108 CFU/g of meat. The tetK gene is located on a small mobilizable plasmid close to Staphylococcus aureus pT181 plasmid. In conclusion, the transfer of tetracycline resistance between strains of S. Xylosus is possible, but at a really low frequency in vitro and in situ in fermented sausages. Even if this represents a very moderate risk, it should be taken into account as required by the European approach of Qualified Presumption of Safety (QPS) and AFSSA safety recommendations, advising that strains used as starter cultures should not carry any transferable antibiotic resistance.
-
Evidence for nitric oxide synthase activity in Staphylococcus Xylosus mediating nitrosoheme formation
Frontiers in Microbiology, 2017Co-Authors: Geoffrey Ras, Véronique Zuliani, Patrick Derkx, Tim M Seibert, Sabine Leroy, Régine TalònAbstract:Staphylococcus Xylosus is used as a starter culture in fermented meat products and contributes to color formation by the reduction of nitrate to nitrite. Nitrite is a food additive that is chemically turned to nitric oxide (NO) in meat but its safety has been questioned. The objective of this study was to determine the ability of NO synthase (NOS) of S. Xylosus C2a to produce NO. For this purpose, a nos deletion mutant (Δnos) in S. Xylosus was constructed and NO production was evaluated in a test based on its ability to form nitrosomyoglobin and nitrosoheme. Production of NO was abrogated in the Δnos mutant under aerobic conditions and reduced about 35-40% comparing to the wild type C2a under limited oxygenation. This mutant was sensitive to oxidative stress. The expression of genes encoding catalase was modulated in the mutant with an up-regulation of katA and a down-regulation of katB and katC. The Δnos mutant displayed high colony pigmentation after prolonged growth on agar medium. Finally, the Δnos mutant showed no growth in minimal medium. Growth was not restored in the minimal medium by complementation with nos, but was restored by either addition of phenylalanine or complementation with pdt, a gene that encodes a prephenate dehydratase involved in phenylalanine biosynthesis and co-transcribed with nos. Our findings clearly demonstrate NOS-mediated NO production in S. Xylosus, a meat-associated coagulase-negative Staphylococcus.
Alison Macfadyen - One of the best experts on this subject based on the ideXlab platform.
-
Staphylococcus pseudoXylosus sp nov isolated from bovine mastitis
International Journal of Systematic and Evolutionary Microbiology, 2019Co-Authors: Alison Macfadyen, Sabine Leroy, Ewan M Harrison, Julian Parkhill, Mark A Holmes, Gavin K PatersonAbstract:Strain S04009T, a Gram-stain-positive, coagulase-negative Staphylococcus, was isolated from bovine mastitis in France. 16S rRNA gene analysis revealed it to be closely related to the coagulase-negative species Staphylococcus Xylosus , Staphylococcus saprophyticus , Staphylococcus caeli and Staphylococcus edaphicus . At the whole-genome level, strain S04009T had an average nucleotide identity value <95 % and an inferred DNA–DNA hybridization value <70 % when compared to these species. Furthermore, phenotypic characteristics distinguished S04009T from those species. From these related species only strain S04009T and S. Xylosus are able to ferment xylose and these two can be distinguished by the inability of strain S04009T to express urease activity. Based on the genotypic and phenotypic results, it is proposed that this isolate is a novel species, with the name Staphylococcus pseudoXylosus sp. nov. The type strain is S04009T (=DSM 107950T=CCUG 72763T=NCTC 14184T).
-
Staphylococcus caeli sp nov isolated from air sampling in an industrial rabbit holding
International Journal of Systematic and Evolutionary Microbiology, 2019Co-Authors: Alison Macfadyen, Ewan M Harrison, Julian Parkhill, Mark A Holmes, Ilenia Drigo, Gavin K PatersonAbstract:Strain 82T, a Gram-stain-positive, coagulase-negative Staphylococcus was isolated from an air sample obtained from an industrial rabbit holding in Italy. It is phylogenetically closely related to the coagulase-negative species Staphylococcus saprophyticus , Staphylococcus Xylosus and Staphylococcus edaphicus . However, it could be distinguished from these species by sequence differences between the 16S rRNA, hsp60, rpoB, dnaJ and gap genes. At the whole genome level, the isolate had an average nucleotide identity of <95 % and an inferred DNA–DNA hybridization of <70 % when compared to these species. Based on the genotypic results, it is proposed that this isolate is a novel species, with the name Staphylococcus caeli sp. nov. The type strain is 82BT (=NCTC 14063T=CCUG 71912T).
Ewan M Harrison - One of the best experts on this subject based on the ideXlab platform.
-
Staphylococcus pseudoXylosus sp nov isolated from bovine mastitis
International Journal of Systematic and Evolutionary Microbiology, 2019Co-Authors: Alison Macfadyen, Sabine Leroy, Ewan M Harrison, Julian Parkhill, Mark A Holmes, Gavin K PatersonAbstract:Strain S04009T, a Gram-stain-positive, coagulase-negative Staphylococcus, was isolated from bovine mastitis in France. 16S rRNA gene analysis revealed it to be closely related to the coagulase-negative species Staphylococcus Xylosus , Staphylococcus saprophyticus , Staphylococcus caeli and Staphylococcus edaphicus . At the whole-genome level, strain S04009T had an average nucleotide identity value <95 % and an inferred DNA–DNA hybridization value <70 % when compared to these species. Furthermore, phenotypic characteristics distinguished S04009T from those species. From these related species only strain S04009T and S. Xylosus are able to ferment xylose and these two can be distinguished by the inability of strain S04009T to express urease activity. Based on the genotypic and phenotypic results, it is proposed that this isolate is a novel species, with the name Staphylococcus pseudoXylosus sp. nov. The type strain is S04009T (=DSM 107950T=CCUG 72763T=NCTC 14184T).
-
Staphylococcus caeli sp nov isolated from air sampling in an industrial rabbit holding
International Journal of Systematic and Evolutionary Microbiology, 2019Co-Authors: Alison Macfadyen, Ewan M Harrison, Julian Parkhill, Mark A Holmes, Ilenia Drigo, Gavin K PatersonAbstract:Strain 82T, a Gram-stain-positive, coagulase-negative Staphylococcus was isolated from an air sample obtained from an industrial rabbit holding in Italy. It is phylogenetically closely related to the coagulase-negative species Staphylococcus saprophyticus , Staphylococcus Xylosus and Staphylococcus edaphicus . However, it could be distinguished from these species by sequence differences between the 16S rRNA, hsp60, rpoB, dnaJ and gap genes. At the whole genome level, the isolate had an average nucleotide identity of <95 % and an inferred DNA–DNA hybridization of <70 % when compared to these species. Based on the genotypic results, it is proposed that this isolate is a novel species, with the name Staphylococcus caeli sp. nov. The type strain is 82BT (=NCTC 14063T=CCUG 71912T).
-
A Staphylococcus Xylosus Isolate with a New mecC Allotype
Antimicrobial Agents and Chemotherapy, 2013Co-Authors: Ewan M Harrison, Vincent Perreten, Sabine Leroy, Gavin K Paterson, Matthew T. G. Holden, Fiona J. E. Morgan, Anders Rhod Larsen, Andreas Petersen, Sarne De Vliegher, Lawrence K. FoxAbstract:Recently, a novel variant of mecA known as mecC (mecA(LGA251)) was identified in Staphylococcus aureus isolates from both humans and animals. In this study, we identified a Staphylococcus Xylosus isolate that harbors a new allotype of the mecC gene, mecC1. Whole-genome sequencing revealed that mecC1 forms part of a class E mec complex (mecI-mecR1-mecC1-blaZ) located at the orfX locus as part of a likely staphylococcal cassette chromosome mec element (SCCmec) remnant, which also contains a number of other genes present on the type XI SCCmec.