Grunert/Vetmeduni Vienna

The pesky bacterium Staphylococcus aureus (S. aureus), best known for causing staph infections such as MRSA, ranges dramatically in form. In fact, recent studies indicate that S. aureus performs an efficient little microevolution to adapt to its host, so that it can evade the immune system and even survive antibiotics.

Not to be outdone by the seeming intelligence of the bacterium, scientists at the University of Veterinary Medicine Vienna say they have devised a technique using infrared light to distinguish between strains of S. aureus that can cause chronic infections and those that cannot. They report their findings in the Journal of Clinical Microbiology.

S. aureus can colonize the skin and upper respiratory tract of humans and can be especially dangerous in those with already weakened immune systems. It even likes cattle, and can inflame their udders.

There are many strains of the bacterium, ranging from aggressive types that form capsules and multiply rapidly to capsule-free types that tend to fare better within cells and be less easily recognized by the host's immune system.

The team out of Venice says its approach employs the procedure called Fourier Transform Infrared Spectroscopy (FTIR). The procedure not only uses infrared light, but also artificial intelligence that analyzes the resulting spectral data to determine what type of capsule the bacterium has formed. "With the new method we can routinely test patient samples with a success rate of up to 99 per cent," researcher Tom Grunert said in a news release.

The researchers say they hope that knowing the specific virulence and persistence of the bacteria will help scientists develop better therapies to treat resulting infections.