Natural population dynamics and expansion of pathogenic clones of Staphylococcus aureus
Damian C. Melles, … , Henri A. Verbrugh, Alex van Belkum
Damian C. Melles, … , Henri A. Verbrugh, Alex van Belkum
Published December 15, 2004
Citation Information: J Clin Invest. 2004;114(12):1732-1740. https://doi.org/10.1172/JCI23083.
View: Text | PDF
Article Infectious disease

Natural population dynamics and expansion of pathogenic clones of Staphylococcus aureus

Abstract

The population structure of Staphylococcus aureus carried by healthy humans was determined using a large strain collection of nonclinical origin (n = 829). High-throughput amplified fragment length polymorphism (AFLP) analysis revealed 3 major and 2 minor genetic clusters of S. aureus, which were corroborated by multilocus sequence typing. Major AFLP cluster I comprised 44.4% of the carriage isolates and showed additional heterogeneity whereas major AFLP groups II and III presented 2 homogeneous clusters, including 47.3% of all carriage isolates. Coanalysis of invasive S. aureus strains and epidemic methicillin-resistant S. aureus (MRSA) revealed that all major clusters contained invasive and multiresistant isolates. However, clusters and subclusters with overrepresentation of invasive isolates were also identified. Bacteremia in elderly adults, for instance, was caused by a IVa cluster–derived strain significantly more often than by strains from other AFLP clusters. Furthermore, expansion of multiresistant clones or clones associated with skin disease (impetigo) was detected, which suggests that epidemic potential is present in pathogenic strains of S. aureus. In addition, the virulence gene encoding Panton-Valentine leukocidin was significantly enriched in S. aureus strains causing abscesses and arthritis in comparison with the carriage group. We provide evidence that essentially any S. aureus genotype carried by humans can transform into a life-threatening human pathogen but that certain clones are more virulent than others.

Authors

Damian C. Melles, Raymond F.J. Gorkink, Hélène A.M. Boelens, Susan V. Snijders, Justine K. Peeters, Michael J. Moorhouse, Peter J. van der Spek, Willem B. van Leeuwen, Guus Simons, Henri A. Verbrugh, Alex van Belkum

×

Figure 3

Options: View larger image (or click on image) Download as PowerPoint
Cluster analysis of the 1,056 S. aureus strains using OmniViz. The cells...
Cluster analysis of the 1,056 S. aureus strains using OmniViz. The cells in the correlation visualization are colored by Pearson’s correlation coefficient values with deeper colors indicating higher positive (red) or negative (blue) correlations. The scale bar (underneath the figure) indicates 100% correlation (red) toward 100% anticorrelation (blue). In order to reveal correlation patterns, a matrix-ordering method was applied to rearrange the samples. The OmniViz correlation view generated with 1,056 strains was adapted so that descriptive (clinical) parameters could be plotted directly adjacent to the original diagonal. The black and white bar on the left indicates the 5 AFLP groups based on PCA. This figure shows additional subclustering in major group I (a–j) as well as in minor group IVa, indicated by several lines. The dotted lines identify blocks of minimal changes in 1 cluster or subcluster. The corresponding MLST data (see also Figure 4) are shown on the right side of the figure. The distributions of the strains from different origins are visualized as red lines in the diagonal red and green bars of the figure (numbered 2–9). Variable 1 indicates the different AFLP clusters based on PCA; 2, carriage isolates, children (n = 400); 3, carriage isolates, elderly adults (n = 429); 4, invasive isolates, total (n = 164); 5, invasive isolates, children (n = 74); 6, invasive isolates, elderly adults (n = 90); 7, invasive isolates, children (deep-seated and soft-tissue infections) (n = 18); 8, impetigo isolates (n = 40); 9, MRSA (n = 21).