Detecting bacterial pathogen species with LIBS

BioPhotonics staff

Life-threatening hospital-acquired bacterial pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) are on the rise; however, scientists have found a way to detect them in less than a minute using laser-induced breakdown spectroscopy (LIBS). Via chemometric analysis of LIBS data, they have also been able to distinguish between strains of bacteria that are resistant to more than one antibiotic.

Bacterial breakdown

The LIBS technique directs a focused laser pulse into a solid, liquid or a gas, where the target material is vaporized, atomized and ionized by energy from the pulse, producing a microplasma. As the electrons switch from an excited state to a lower-energy state, light is emitted.

Scientists from Applied Research Associates have used the Andor iStar CCD camera to detect life-threatening hospital-acquired bacterial pathogen species. Courtesy of Andor Technologies.

In a blind test, scientists at Applied Research Associates, led by Dr. Rosalie Multari, analyzed 10 accumulated spectra from the laser-induced plasma plumes of bacteria samples. The specimens included Escherichia coli and three strains of MRSA. Using an iStar intensified-CCD camera from Andor Technology plc, coupled with an echelle-based spectrograph, they determined that five of the samples were pathogenic.

Because the system permits the spectrum to be delayed by 1 µs from the laser pulse and integrated on a 20-µs temporal scale for an overall 1-s detection period, the five samples were identified with complete accuracy, the company said.