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Comparison of biofilm formation between major clonal lineages of methicillin resistant Staphylococcus aureus.

Vanhommerig E, Moons P, Pirici D, Lammens C, Hernalsteens JP, De Greve H, Kumar-Singh S, Goossens H, Malhotra-Kumar S - PLoS ONE (2014)

Bottom Line: Only 16 strains successfully formed biofilms under both conditions, of which 13 harboured SCCmec IV and included all tested USA300 strains (n = 3).However, USA300 demonstrated remarkably lower percentages of cell-occupied space (6.6%) compared to the other clones (EMRSA-15 = 19.0%) under dynamic conditions.USA300 demonstrated abundant biofilm formation under both conditions, which probably confers a competitive advantage, contributing to its remarkable success as a pathogen.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Microbiology, University of Antwerp, Antwerp, Belgium; Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.

ABSTRACT

Objectives: Epidemic methicillin-resistant S. aureus (MRSA) clones cause infections in both hospital and community settings. As a biofilm phenotype further facilitates evasion of the host immune system and antibiotics, we compared the biofilm-forming capacities of various MRSA clones.

Methods: Seventy-six MRSA classified into 13 clones (USA300, EMRSA-15, Hungarian/Brazilian etc.), and isolated from infections or from carriers were studied for biofilm formation under static and dynamic conditions. Static biofilms in microtitre plates were quantified colorimetrically. Dynamic biofilms (Bioflux 200, Fluxion, USA) were studied by confocal laser-scanning and time-lapse microscopy, and the total volume occupied by live/dead bacteria quantified by Volocity 5.4.1 (Improvision, UK).

Results: MRSA harbouring SCCmec IV produced significantly more biomass under static conditions than SCCmec I-III (P = 0.003), and those harbouring SCCmec II significantly less than those harbouring SCCmec I or III (P<0.001). In the dynamic model, SCCmec I-III harbouring MRSA were significantly better biofilm formers than SCCmec IV (P = 0.036). Only 16 strains successfully formed biofilms under both conditions, of which 13 harboured SCCmec IV and included all tested USA300 strains (n = 3). However, USA300 demonstrated remarkably lower percentages of cell-occupied space (6.6%) compared to the other clones (EMRSA-15 = 19.0%) under dynamic conditions. Time-lapse microscopy of dynamic biofilms demonstrated that USA300 formed long viscoelastic tethers that stretched far from the point of attachment, while EMRSA-15 consisted of micro-colonies attached densely to the surface.

Conclusions: MRSA harbouring SCCmec types IV and I-III demonstrate distinct biofilm forming capacities, possibly owing to their adaptation to the community and hospital settings, respectively. USA300 demonstrated abundant biofilm formation under both conditions, which probably confers a competitive advantage, contributing to its remarkable success as a pathogen.

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Related in: MedlinePlus

Box-whisker plot of biofilm formation by MRSA clones in the static assay.Boxes depict the 95% CI, black horizontal lines the average OD492 value, and the whiskers the OD492 value range (lowest and highest values) for each clone.
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pone-0104561-g001: Box-whisker plot of biofilm formation by MRSA clones in the static assay.Boxes depict the 95% CI, black horizontal lines the average OD492 value, and the whiskers the OD492 value range (lowest and highest values) for each clone.

Mentions: Within the different clones of the SCCmec IV group, all SCCmec IV strains belonging to CC22 (EMRSA-15, n = 7) and CC8 (USA300, n = 3; USA500, n = 8) exhibited strong biofilm formation with ODs ranging from 0.036–0.183 and 0.032–0.392, respectively (Figure 1), and average OD values of USA300 (OD492 = 0.125, SD = 0.024), USA500 (OD492 = 0.090, SD = 0.122), and EMRSA-15 (OD492 = 0.087, SD = 0.052) being the highest of the MRSA clones tested here. On the other end of the spectrum, the lowest average OD values were associated with the Southern German (OD492 = 0.014, SD = 0.012), New York/Japan (OD492 = 0.018, SD = 0.004), E-MRSA 16 (OD492 = 0.015, SD = 0.013), South-West Pacific (OD492 = 0.007, SD = 0.006) and especially, USA600 (OD492 = 0.002, SD = 0.001) clones. No correlation was observed between site of infection (P = 0.919) or presence of pvl (P = 0.187) and biofilm formation. In our study, the presence of ACME was uniquely associated with USA300 and thus high amounts of biomass (P = 0.011).


Comparison of biofilm formation between major clonal lineages of methicillin resistant Staphylococcus aureus.

Vanhommerig E, Moons P, Pirici D, Lammens C, Hernalsteens JP, De Greve H, Kumar-Singh S, Goossens H, Malhotra-Kumar S - PLoS ONE (2014)

Box-whisker plot of biofilm formation by MRSA clones in the static assay.Boxes depict the 95% CI, black horizontal lines the average OD492 value, and the whiskers the OD492 value range (lowest and highest values) for each clone.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126748&req=5

pone-0104561-g001: Box-whisker plot of biofilm formation by MRSA clones in the static assay.Boxes depict the 95% CI, black horizontal lines the average OD492 value, and the whiskers the OD492 value range (lowest and highest values) for each clone.
Mentions: Within the different clones of the SCCmec IV group, all SCCmec IV strains belonging to CC22 (EMRSA-15, n = 7) and CC8 (USA300, n = 3; USA500, n = 8) exhibited strong biofilm formation with ODs ranging from 0.036–0.183 and 0.032–0.392, respectively (Figure 1), and average OD values of USA300 (OD492 = 0.125, SD = 0.024), USA500 (OD492 = 0.090, SD = 0.122), and EMRSA-15 (OD492 = 0.087, SD = 0.052) being the highest of the MRSA clones tested here. On the other end of the spectrum, the lowest average OD values were associated with the Southern German (OD492 = 0.014, SD = 0.012), New York/Japan (OD492 = 0.018, SD = 0.004), E-MRSA 16 (OD492 = 0.015, SD = 0.013), South-West Pacific (OD492 = 0.007, SD = 0.006) and especially, USA600 (OD492 = 0.002, SD = 0.001) clones. No correlation was observed between site of infection (P = 0.919) or presence of pvl (P = 0.187) and biofilm formation. In our study, the presence of ACME was uniquely associated with USA300 and thus high amounts of biomass (P = 0.011).

Bottom Line: Only 16 strains successfully formed biofilms under both conditions, of which 13 harboured SCCmec IV and included all tested USA300 strains (n = 3).However, USA300 demonstrated remarkably lower percentages of cell-occupied space (6.6%) compared to the other clones (EMRSA-15 = 19.0%) under dynamic conditions.USA300 demonstrated abundant biofilm formation under both conditions, which probably confers a competitive advantage, contributing to its remarkable success as a pathogen.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Microbiology, University of Antwerp, Antwerp, Belgium; Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.

ABSTRACT

Objectives: Epidemic methicillin-resistant S. aureus (MRSA) clones cause infections in both hospital and community settings. As a biofilm phenotype further facilitates evasion of the host immune system and antibiotics, we compared the biofilm-forming capacities of various MRSA clones.

Methods: Seventy-six MRSA classified into 13 clones (USA300, EMRSA-15, Hungarian/Brazilian etc.), and isolated from infections or from carriers were studied for biofilm formation under static and dynamic conditions. Static biofilms in microtitre plates were quantified colorimetrically. Dynamic biofilms (Bioflux 200, Fluxion, USA) were studied by confocal laser-scanning and time-lapse microscopy, and the total volume occupied by live/dead bacteria quantified by Volocity 5.4.1 (Improvision, UK).

Results: MRSA harbouring SCCmec IV produced significantly more biomass under static conditions than SCCmec I-III (P = 0.003), and those harbouring SCCmec II significantly less than those harbouring SCCmec I or III (P<0.001). In the dynamic model, SCCmec I-III harbouring MRSA were significantly better biofilm formers than SCCmec IV (P = 0.036). Only 16 strains successfully formed biofilms under both conditions, of which 13 harboured SCCmec IV and included all tested USA300 strains (n = 3). However, USA300 demonstrated remarkably lower percentages of cell-occupied space (6.6%) compared to the other clones (EMRSA-15 = 19.0%) under dynamic conditions. Time-lapse microscopy of dynamic biofilms demonstrated that USA300 formed long viscoelastic tethers that stretched far from the point of attachment, while EMRSA-15 consisted of micro-colonies attached densely to the surface.

Conclusions: MRSA harbouring SCCmec types IV and I-III demonstrate distinct biofilm forming capacities, possibly owing to their adaptation to the community and hospital settings, respectively. USA300 demonstrated abundant biofilm formation under both conditions, which probably confers a competitive advantage, contributing to its remarkable success as a pathogen.

Show MeSH
Related in: MedlinePlus