Mike the Mad Biologist

Each of the Google Map pins represents a different surveillance laboratory. If you click on the pin, it tells you how many Staphylococcus aureus ('staph') isolates have been typed. You can then click the "view spa types" link. spa is a highly variable genetic locus* that is used to tell S. aureus isolates apart. The site then shows you the number of different spa types found in at that site and how often that type is found at that site and throughout Europe.

What's really cool (to me, anyway) is that the site will show you where else in Europe that site is found, how many isolates were found at other sites, the mortality due to that spa type, the frequency of methicillin resistance in that spa type, and the age distribution of patients infected with that spa type. You can also click on the spa type itself and find out the details of each individual S. aureus isolate.

So other than the 'gee whiz' factor, what good is this system? (Other than keeping microbiologists and computer programmers off the streets....). Well, here's a summary of what this network found so far:

These findings provide the first representative snapshot of the genetic population structure of S. aureus across Europe. Because the researchers used spa typing, which analyzes only a small region of one gene, and characterized only 3,000 isolates, analysis of other parts of the S. aureus genome in more isolates is now needed to build a complete portrait of the geographical abundance of the S. aureus clones that cause invasive infections in Europe. However, the finding that MRSA spa types occur mainly in geographical clusters has important implications for the control of MRSA, because it indicates that a limited number of clones are spreading within health care networks, which means that MRSA is mainly spread by patients who are repeatedly admitted to different hospitals. Control efforts aimed at interrupting this spread within and between health care institutions may be feasible and ultimately successful, suggest the researchers, and should be strongly encouraged. In addition, this study shows how, by sharing typing results on a Web-based platform, an international surveillance network can provide clinicians and infection control teams with crucial information about the dynamics of pathogens such as S. aureus, including early warnings about emerging virulent clones.

We actually now have a strategy for limiting or even stopping the spread of MRSA in Europe: rigorously screen, or even prospectively isolate patients who visit multiple medical facilities regularly.

This is why surveillance matters.

*There are other typing methods, and as the PLoS Medicine editors note, they need to be applied to these isolates too.

Cited articles: Lowy FD (2010) Mapping the Distribution of Invasive Staphylococcus aureus across Europe. PLoS Med 7(1): e1000205. doi:10.1371/journal.pmed.1000205

Grundmann H, Aanensen DM, van den Wijngaard CC, Spratt BG, Harmsen D, et al. (2010) Geographic Distribution of Staphylococcus aureus Causing Invasive Infections in Europe: A Molecular-Epidemiological Analysis. PLoS Med 7(1): e1000215. doi:10.1371/journal.pmed.1000215