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Scientific Reports Jul 2023The foodborne bacterium Staphylococcus equorum strain KS1030 harbours plasmid pSELNU1, which encodes a lincomycin resistance gene. pSELNU1 undergoes horizontal transfer...
The foodborne bacterium Staphylococcus equorum strain KS1030 harbours plasmid pSELNU1, which encodes a lincomycin resistance gene. pSELNU1 undergoes horizontal transfer between bacterial strains, thus spreading antibiotic resistance. However, the genes required for horizontal plasmid transfer are not encoded in pSELNU1. Interestingly, a relaxase gene, a type of gene related to horizontal plasmid transfer, is encoded in another plasmid of S. equorum KS1030, pKS1030-3. The complete genome of pKS1030-3 is 13,583 bp long and encodes genes for plasmid replication, biofilm formation (the ica operon), and horizontal gene transfer. The replication system of pKS1030-3 possesses the replication protein-encoding gene repB, a double-stranded origin of replication, and two single-stranded origins of replication. The ica operon, relaxase gene, and a mobilization protein-encoding gene were detected in pKS1030-3 strain-specifically. When expressed in S. aureus RN4220, the ica operon and relaxase operon of pKS1030-3 conferred biofilm formation ability and horizontal gene transfer ability, respectively. The results of our analyses show that the horizontal transfer of pSELNU1 of S. equorum strain KS1030 depends on the relaxase encoded by pKS1030-3, which is therefore trans-acting. Genes encoded in pKS1030-3 contribute to important strain-specific properties of S. equorum KS1030. These results could contribute to preventing the horizontal transfer of antibiotic resistance genes in food.
Topics: Staphylococcus aureus; Staphylococcus; Plasmids; Biofilms
PubMed: 37429971
DOI: 10.1038/s41598-023-38274-8 -
International Journal of Food... Nov 2023Penicillium nordicum is one of the major producers of ochratoxin A (OTA) in dry-cured ham. Staphylococcus xylosus Sx8 and Staphylococcus equorum Se31 have been...
Penicillium nordicum is one of the major producers of ochratoxin A (OTA) in dry-cured ham. Staphylococcus xylosus Sx8 and Staphylococcus equorum Se31 have been previously proposed as biocontrol agents (BCAs) to prevent the OTA contamination, although their antifungal mode of action has not been established yet. Thus, the aim of this work was to elucidate their mode of action against P. nordicum in a dry-cured ham model system. For this, the effect of live cells, dead cells, and cell-free broth; the nutritional utilisation pattern, niche overlap index (NOI), interactions by dual-culture assays, antifungal effect of volatile compounds, OTA detoxification, and effect on fungal proteome were determined. No fungal growth was observed after 14 days of co-culture with live cells of each staphylococcus at 15 or 20 °C. However, such inhibition was not observed with either dead cells or extracellular extracts. The number of carbon sources utilised by P. nordicum was higher than those used by both cocci at 20 °C, whilst the opposite occurred at 15 °C. According to NOI, nutritional dominance depends on temperature, at 20 °C P. nordicum dominated the niche, but at 15 °C the mould is dominated by the BCAs. The volatile pattern generated by each coccus did not show antifungal effect, and both staphylococci failed to degrade or adsorb OTA. However, in the interaction assay, S. xylosus and S. equorum were able to decrease the fungal growth and its OTA production. In addition, proteomic analyses showed changes in the abundance of proteins related to the cell wall integrity (CWI), carbohydrate metabolism and the biosynthesis of secondary metabolites such as OTA. In conclusion, overall, the antagonistic effects of the two studied cocci against P. nordicum are greater at 15 °C than at 20 °C, being linked to competition for space and nutrients, triggering alterations in CWI pathway, OTA biosynthesis, and carbohydrate metabolism.
Topics: Food Microbiology; Pork Meat; Proteomics; Antifungal Agents; Meat Products; Ochratoxins; Penicillium; Staphylococcus
PubMed: 37523903
DOI: 10.1016/j.ijfoodmicro.2023.110342 -
Journal of Medical Microbiology May 2006A polyphasic identification approach was applied to a group of 11 novobiocin-resistant staphylococci isolated from human clinical materials. Phenotypic characteristics...
A polyphasic identification approach was applied to a group of 11 novobiocin-resistant staphylococci isolated from human clinical materials. Phenotypic characteristics obtained by both commercial and conventional tests assigned eight strains as Staphylococcus xylosus and three strains as ambiguous S. xylosus/Staphylococcus equorum. In contrast to biotyping, ribotyping with EcoRI and HindIII restriction endonucleases and whole-cell protein fingerprinting assigned six analysed strains as S. equorum, and five strains as Staphylococcus succinus. Confirmation of the identification was done by partial 16S rRNA gene sequencing and S. equorum isolates were verified by a PCR assay targeting the sodA gene. From the data it has been implied that ribotyping and whole-cell protein analysis can be used to differentiate between the biochemically almost indistinguishable species S. xylosus, S. equorum and S. succinus. The present study confirms what is believed to be the first occurrence of S. equorum in a relevant human clinical material in the Czech Republic and describes what is believed to be the first-ever isolation of S. succinus from human clinical material.
Topics: Adolescent; Aged; Aged, 80 and over; Anti-Bacterial Agents; Bacterial Proteins; Bacterial Typing Techniques; Child; Cluster Analysis; DNA, Bacterial; DNA, Ribosomal; Drug Resistance, Bacterial; Female; Humans; Infant; Male; Middle Aged; Molecular Sequence Data; Novobiocin; Polymerase Chain Reaction; Proteome; RNA, Ribosomal, 16S; Ribotyping; Sequence Analysis, DNA; Staphylococcal Infections; Staphylococcus; Superoxide Dismutase
PubMed: 16585638
DOI: 10.1099/jmm.0.46246-0 -
Scientific Reports Sep 2022Staphylococcus equorum strain KM1031 is resistant to chloramphenicol, erythromycin and lincomycin. To shed light on the genetic factors underlying these antibiotic...
Staphylococcus equorum strain KM1031 is resistant to chloramphenicol, erythromycin and lincomycin. To shed light on the genetic factors underlying these antibiotic resistances, we determined the global gene expression profile of S. equorum KM1031 using RNA sequencing. During chloramphenicol, erythromycin and lincomycin treatment, 8.3% (183/2,336), 16.0% (354/2,336), and 2.9% (63/2,336) of S. equorum KM1031 genes exhibited significant differences in expression, respectively. These three antibiotics upregulated genes related to efflux and downregulated genes related to transporters. Antibiotic treatment also upregulated osmoprotectant-related genes involved in salt tolerance. To identify specific genes functionally related to antibiotic resistance, we compared the genome of strain KM1031 with those of three S. equorum strains that are sensitive to these three antibiotics. We identified three genes of particular interest: an antibiotic biosynthesis monooxygenase gene (abm, AWC34_RS01805) related to chloramphenicol resistance, an antibiotic ABC transporter ATP-binding protein gene (msr, AWC34_RS11115) related to erythromycin resistance, and a lincosamide nucleotydyltransferase gene (lnuA, AWC34_RS13300) related to lincomycin resistance. These genes were upregulated in response to the corresponding antibiotic; in particular, msr was upregulated more than fourfold by erythromycin treatment. Finally, the results of RNA sequencing were validated by quantitative real-time PCR. This transcriptomic analysis provides genetic evidence regarding antibiotic stress responses of S. equorum strain KM1031.
Topics: ATP-Binding Cassette Transporters; Adenosine Triphosphate; Anti-Bacterial Agents; Chloramphenicol; Erythromycin; Fermented Foods; Lincomycin; Mixed Function Oxygenases; Staphylococcus; Transcriptome
PubMed: 36109627
DOI: 10.1038/s41598-022-19897-9 -
Journal of Structural Biology Jun 2021The dimeric form of manganese superoxide dismutase is instrumental for activity because each of the monomers provides amino acid residues participating in the enzymatic...
The dimeric form of manganese superoxide dismutase is instrumental for activity because each of the monomers provides amino acid residues participating in the enzymatic reaction. Hence, preventing dissociation of the dimer would maintain the enzymatic activity in detrimental conditions e.g. high temperature. To prevent dissociation of the dimer, a disulphide (S-S) bond was introduced at the dimer interface. In the wild type structure, S126 interacts with S126 of the other monomer. In the presented work, a mutant was designed with an S126C substitution. The crystal structure of the S126C mutant showed that only 50-70% of monomers formed the S-S bond. This observed imperfect S-S bonding was likely caused by photolytic S-S bond breakage mediated by the neighbouring tryptophan residue. In the wild type, S126 is located facing W163 and forms a water-mediated hydrogen bond with E164; W163 and E164 are crucial in the enzyme's activity. The replacement of S126 by a cysteine residue lowered the activity of the enzyme by ~70%. S126 has never been considered to play a role in the enzyme's activity or stability, thus the finding showed the importance of this residue.
Topics: Amino Acid Substitution; Bacterial Proteins; Crystallography, X-Ray; Disulfides; Hydrogen Bonding; Models, Molecular; Protein Multimerization; Protein Stability; Serine; Staphylococcus; Superoxide Dismutase; Tryptophan
PubMed: 33794368
DOI: 10.1016/j.jsb.2021.107731 -
International Journal of Environmental... Jul 2021Dry-cured sausages are traditional in Mediterranean countries, and Paio do Alentejo (PA) is one of the most popular in South Portugal. The aim of the present work was to...
Dry-cured sausages are traditional in Mediterranean countries, and Paio do Alentejo (PA) is one of the most popular in South Portugal. The aim of the present work was to evaluate the effect of combined starters on the safety and quality of PA preserving its sensory quality. Physicochemical parameters, namely pH and water activity (a), microbiological parameters, biogenic amines, color, texture, and sensory attributes were assessed. Three starter cultures were used, namely S2M7 and CV3C2, both separate and combined with the 2RB4 yeast strain at a concentration of 10 cfu/g. Dextrose 0.25% was added to the meat batter. Starters had a significant effect on the reduction of a values (0.845 to 0.823). The treatment with as well as the co-inoculation of with effectively reduced the counts to undetectable levels. Sausages co-inoculated with S2M7/ CV3C2 showed a significant reduction in the content of vasoactive amines, namely tryptamine (26.21 to 15.70) and β-phenylethylamine (4.80 to 3.69). Regarding texture, control PA showed higher hardness values, and the starters promoted the cohesiveness of the batter while reducing chewiness. The studied starters did not compromise the sensory characteristics of PA.
Topics: Biogenic Amines; Fermentation; Food Microbiology; Latilactobacillus sakei; Meat Products; Portugal; Staphylococcus
PubMed: 34281032
DOI: 10.3390/ijerph18137100 -
Journal of Bacteriology Sep 2012Staphylococcus equorum subsp. equorum is a member of the coagulase-negative staphylococcus group and is frequently isolated from fermented food products and from...
Staphylococcus equorum subsp. equorum is a member of the coagulase-negative staphylococcus group and is frequently isolated from fermented food products and from food-processing environments. It contributes to the formation of aroma compounds during the ripening of fermented foods, especially cheeses and sausages. Here, we report the draft genome sequence of Staphylococcus equorum subsp. equorum Mu2 to provide insights into its physiology and compare it with other Staphylococcus species.
Topics: Cheese; DNA, Bacterial; Genome, Bacterial; Molecular Sequence Data; Sequence Analysis, DNA; Staphylococcus
PubMed: 22933766
DOI: 10.1128/JB.01038-12 -
International Journal of Molecular... Jul 2023In food, bacteria carrying antibiotic resistance genes could play a prominent role in the spread of resistance. populations can become large in a number of fermented...
In food, bacteria carrying antibiotic resistance genes could play a prominent role in the spread of resistance. populations can become large in a number of fermented foods, yet the antibiotic resistance properties of this species have been little studied. In this work, the resistance/susceptibility (R/S) profile of strains ( = 30) from cheese to 16 antibiotics was determined by broth microdilution. The minimum inhibitory concentration (MIC) for all antibiotics was low in most strains, although higher MICs compatible with acquired genes were also noted. Genome analysis of 13 strains showed the resistome to be composed of intrinsic mechanisms, acquired mutations, and acquired genes. As such, a plasmidic gene providing resistance to chloramphenicol was found in one strain; this was able to provide resistance to after electroporation. An (A) polymorphic gene was identified in five strains. The Mrs(A) variants were associated with variable resistance to erythromycin. However, the genetic data did not always correlate with the phenotype. As such, all strains harbored a polymorphic / gene, although only one acquired copy was associated with strong resistance to fosfomycin. Similarly, a plasmid-associated operon encoding a penicillinase system was identified in five ampicillin- and penicillin G-susceptible strains. Identified genes not associated with phenotypic resistance further included (C) in two strains and in all strains. The antibiotic R/S status and gene content of strains intended to be employed in food systems should be carefully determined.
Topics: Anti-Bacterial Agents; Cheese; Food Microbiology; Drug Resistance, Microbial; Microbial Sensitivity Tests
PubMed: 37511416
DOI: 10.3390/ijms241411657 -
MSphere Aug 2023The observation that molds can inhibit the growth of was a catalyst for the antibiotic revolution. Considerable attention has been paid to purified metabolites that...
The observation that molds can inhibit the growth of was a catalyst for the antibiotic revolution. Considerable attention has been paid to purified metabolites that inhibit bacteria, but little is known about how species impact the ecology and evolution of bacteria in multispecies microbial communities. Here, we investigated how four different species of can impact global transcription and evolution of a widespread species () using the cheese rind model microbiome. Through RNA sequencing, we identified a core transcriptional response of against all five tested strains, including upregulation of thiamine biosynthesis, fatty acid degradation, and amino acid metabolism as well as downregulation of genes involved in the transport of siderophores. In a 12-week evolution experiment where we co-cultured with the same strains, we observed surprisingly few non-synonymous mutations across populations evolved with the species. A mutation in a putative DHH family phosphoesterase gene only occurred in populations evolved without and decreased the fitness of when co-cultured with an antagonistic strain. Our results highlight the potential for conserved mechanisms of interactions and demonstrate how fungal biotic environments may constrain the evolution of bacterial species.IMPORTANCEFungi and bacteria are commonly found co-occurring both in natural and synthetic microbiomes, but our understanding of fungal-bacterial interactions is limited to a handful of species. Conserved mechanisms of interactions and evolutionary consequences of fungal-bacterial interactions are largely unknown. Our RNA sequencing and experimental evolution data with species and the bacterium demonstrate that divergent fungal species can elicit conserved transcriptional and genomic responses in co-occurring bacteria. molds are integral to the discovery of novel antibiotics and production of certain foods. By understanding how species affect bacteria, our work can further efforts to design and manage -dominated microbial communities in industry and food production.
Topics: Transcriptome; Cheese; Penicillium; Bacteria; Staphylococcus; Fungi; Anti-Bacterial Agents
PubMed: 37219436
DOI: 10.1128/msphere.00047-23 -
Folia Microbiologica May 2014Staphylococcus xylosus, Staphylococcus equorum, and Staphylococcus epidermidis strains were isolated from Bryndza cheese and identified using PCR method. The...
Staphylococcus xylosus, Staphylococcus equorum, and Staphylococcus epidermidis strains were isolated from Bryndza cheese and identified using PCR method. The antimicrobial susceptibility of these strains was assessed using disc diffusion method and broth microdilution method. The highest percentage of resistance was detected for ampicillin and oxacillin, and in contrary, isolates were susceptible or intermediate resistant to ciprofloxacin and chloramphenicol. Fourteen of the S. xylosus isolates (45%) and eleven of the S. equorum isolates (41%) exhibited multidrug resistance. None of the S. epidermidis isolate was multiresistant. The phenotypic resistance to oxacillin was verified by PCR amplification of the gene mecA.
Topics: Anti-Bacterial Agents; Cheese; Drug Resistance, Bacterial; Food Microbiology; Methicillin Resistance; Microbial Sensitivity Tests; Staphylococcus
PubMed: 24142792
DOI: 10.1007/s12223-013-0286-y