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Insights on virulence from the complete genome of Staphylococcus capitis.

Cameron DR, Jiang JH, Hassan KA, Elbourne LD, Tuck KL, Paulsen IT, Peleg AY - Front Microbiol (2015)

Bottom Line: Methylome analysis identified significant adenine methylation across the genome involving two distinct methylation motifs (1972 putative 6-methyladenine (m6A) residues identified).Putative adenine methyltransferases were also identified.Comparative analysis of AYP1020 and the closely related CoNS, S. epidermidis RP62a, revealed a host of virulence factors that likely contribute to S. capitis pathogenicity, most notably genes important for biofilm formation and a suite of phenol soluble modulins (PSMs); the expression/production of these factors were corroborated by functional assays.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Monash University Melbourne, VIC, Australia.

ABSTRACT
Staphylococcus capitis is an opportunistic pathogen of the coagulase negative staphylococci (CoNS). Functional genomic studies of S. capitis have thus far been limited by a lack of available complete genome sequences. Here, we determined the closed S. capitis genome and methylome using Single Molecule Real Time (SMRT) sequencing. The strain, AYP1020, harbors a single circular chromosome of 2.44 Mb encoding 2304 predicted proteins, which is the smallest of all complete staphylococcal genomes sequenced to date. AYP1020 harbors two large mobile genetic elements; a plasmid designated pAYP1020 (59.6 Kb) and a prophage, ΦAYP1020 (48.5 Kb). Methylome analysis identified significant adenine methylation across the genome involving two distinct methylation motifs (1972 putative 6-methyladenine (m6A) residues identified). Putative adenine methyltransferases were also identified. Comparative analysis of AYP1020 and the closely related CoNS, S. epidermidis RP62a, revealed a host of virulence factors that likely contribute to S. capitis pathogenicity, most notably genes important for biofilm formation and a suite of phenol soluble modulins (PSMs); the expression/production of these factors were corroborated by functional assays. The complete S. capitis genome will aid future studies on the evolution and pathogenesis of the coagulase negative staphylococci.

No MeSH data available.


Related in: MedlinePlus

Biofilm formation of S. capitis AYP1020. Scanning electron micrograph of biofilm formed by S. capitis AYP1020 on polyurethane at 10,000X magnification (A). Biofilm was quantified on polystyrene microtitre plates. Data are expressed as mean ± SEM (*P < 0.05) (B). Schematic ClustalW alignment revealed high similarity (71–83% identity) between the IcaRADBC proteins of S. capitis AYP1020 and those of S. epidermidis. White regions represent the same amino acid, gray regions represent similar amino acids and black regions represent non-similar amino acids (C).
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Figure 4: Biofilm formation of S. capitis AYP1020. Scanning electron micrograph of biofilm formed by S. capitis AYP1020 on polyurethane at 10,000X magnification (A). Biofilm was quantified on polystyrene microtitre plates. Data are expressed as mean ± SEM (*P < 0.05) (B). Schematic ClustalW alignment revealed high similarity (71–83% identity) between the IcaRADBC proteins of S. capitis AYP1020 and those of S. epidermidis. White regions represent the same amino acid, gray regions represent similar amino acids and black regions represent non-similar amino acids (C).

Mentions: Biofilm formation is highly important for CoNS pathogenicity as they allow bacteria to colonize abiotic surfaces such as indwelling medical devices, which helps to establish infections within the host (Von Eiff et al., 2002). Using SEM, we observed S. capitis AYP1020 biofilms on multiple polymeric surfaces including polyurethane (Figure 4A) and silicone (data not shown). Whilst S. capitis AYP1020 was shown to generate biofilm, the relative production of biofilm was six-fold lower than that of S. epidermidis RP62a (Figure 4B). In S. epidermidis, the bifunctional autolysin, AtlE has been shown to be important for initial biofilm attachment to polymeric surfaces (Heilmann et al., 1997). Further, fibronectin binding proteins Fbe and Ebh are important for binding to host extracellular matrix proteins, which coat medical devices upon implantation (Nilsson et al., 1998; Von Eiff et al., 2002; Williams et al., 2002). The molecular mechanisms contributing to S. capitis surface adhesion are less well defined. A study highlighted the importance of microbial surface component recognizing adhesive molecules (MSCRAMMs) SdrX (Liu et al., 2004) and the “SdrZ like” protein SdrZL, each of which are present in the AYP1020 genome. The homologs of AtlE (70% amino acid identity), Fbe (88% amino acid identity), and Ebh (57% amino acid identity) were also identified. Further studies are required to investigate the role of these proteins in S. capitis adhesion.


Insights on virulence from the complete genome of Staphylococcus capitis.

Cameron DR, Jiang JH, Hassan KA, Elbourne LD, Tuck KL, Paulsen IT, Peleg AY - Front Microbiol (2015)

Biofilm formation of S. capitis AYP1020. Scanning electron micrograph of biofilm formed by S. capitis AYP1020 on polyurethane at 10,000X magnification (A). Biofilm was quantified on polystyrene microtitre plates. Data are expressed as mean ± SEM (*P < 0.05) (B). Schematic ClustalW alignment revealed high similarity (71–83% identity) between the IcaRADBC proteins of S. capitis AYP1020 and those of S. epidermidis. White regions represent the same amino acid, gray regions represent similar amino acids and black regions represent non-similar amino acids (C).
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Figure 4: Biofilm formation of S. capitis AYP1020. Scanning electron micrograph of biofilm formed by S. capitis AYP1020 on polyurethane at 10,000X magnification (A). Biofilm was quantified on polystyrene microtitre plates. Data are expressed as mean ± SEM (*P < 0.05) (B). Schematic ClustalW alignment revealed high similarity (71–83% identity) between the IcaRADBC proteins of S. capitis AYP1020 and those of S. epidermidis. White regions represent the same amino acid, gray regions represent similar amino acids and black regions represent non-similar amino acids (C).
Mentions: Biofilm formation is highly important for CoNS pathogenicity as they allow bacteria to colonize abiotic surfaces such as indwelling medical devices, which helps to establish infections within the host (Von Eiff et al., 2002). Using SEM, we observed S. capitis AYP1020 biofilms on multiple polymeric surfaces including polyurethane (Figure 4A) and silicone (data not shown). Whilst S. capitis AYP1020 was shown to generate biofilm, the relative production of biofilm was six-fold lower than that of S. epidermidis RP62a (Figure 4B). In S. epidermidis, the bifunctional autolysin, AtlE has been shown to be important for initial biofilm attachment to polymeric surfaces (Heilmann et al., 1997). Further, fibronectin binding proteins Fbe and Ebh are important for binding to host extracellular matrix proteins, which coat medical devices upon implantation (Nilsson et al., 1998; Von Eiff et al., 2002; Williams et al., 2002). The molecular mechanisms contributing to S. capitis surface adhesion are less well defined. A study highlighted the importance of microbial surface component recognizing adhesive molecules (MSCRAMMs) SdrX (Liu et al., 2004) and the “SdrZ like” protein SdrZL, each of which are present in the AYP1020 genome. The homologs of AtlE (70% amino acid identity), Fbe (88% amino acid identity), and Ebh (57% amino acid identity) were also identified. Further studies are required to investigate the role of these proteins in S. capitis adhesion.

Bottom Line: Methylome analysis identified significant adenine methylation across the genome involving two distinct methylation motifs (1972 putative 6-methyladenine (m6A) residues identified).Putative adenine methyltransferases were also identified.Comparative analysis of AYP1020 and the closely related CoNS, S. epidermidis RP62a, revealed a host of virulence factors that likely contribute to S. capitis pathogenicity, most notably genes important for biofilm formation and a suite of phenol soluble modulins (PSMs); the expression/production of these factors were corroborated by functional assays.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Monash University Melbourne, VIC, Australia.

ABSTRACT
Staphylococcus capitis is an opportunistic pathogen of the coagulase negative staphylococci (CoNS). Functional genomic studies of S. capitis have thus far been limited by a lack of available complete genome sequences. Here, we determined the closed S. capitis genome and methylome using Single Molecule Real Time (SMRT) sequencing. The strain, AYP1020, harbors a single circular chromosome of 2.44 Mb encoding 2304 predicted proteins, which is the smallest of all complete staphylococcal genomes sequenced to date. AYP1020 harbors two large mobile genetic elements; a plasmid designated pAYP1020 (59.6 Kb) and a prophage, ΦAYP1020 (48.5 Kb). Methylome analysis identified significant adenine methylation across the genome involving two distinct methylation motifs (1972 putative 6-methyladenine (m6A) residues identified). Putative adenine methyltransferases were also identified. Comparative analysis of AYP1020 and the closely related CoNS, S. epidermidis RP62a, revealed a host of virulence factors that likely contribute to S. capitis pathogenicity, most notably genes important for biofilm formation and a suite of phenol soluble modulins (PSMs); the expression/production of these factors were corroborated by functional assays. The complete S. capitis genome will aid future studies on the evolution and pathogenesis of the coagulase negative staphylococci.

No MeSH data available.


Related in: MedlinePlus