质谱分析法可快速检测葡萄球菌感染

Researchers from the Georgia Institute of Technology and the Centers for Disease Control and Prevention (CDC) have developed a new laboratory test that can rapidly identify the bacterium¹（细菌） responsible for staph（葡萄球菌） infections. This new test takes advantage of unique isotopic² labeling combined with specific bacteriophage（噬菌体） amplification³ to rapidly identify Staphylococcus aureus. Quickly and accurately⁴ detecting infections caused by S. aureus is critical because the pathogenic bacterium causes a broad spectrum⁵ of infections, ranging from acute to chronic⁶ disease, which need to be treated in a prompt manner with the correct antibiotic⁷. #

The test uses mass spectrometry to quantify the number of S. aureus organisms in a large number of samples in just a few hours, compared to a day or two for culturing techniques typically used to detect this bacterium.

"Our method for detecting staph infections using mass spectrometry will be valuable in a variety of situations, but will be crucial when a large number of people need to be tested very quickly, which will ultimately improve treatment," said Facundo Fernández, an associate professor in the Georgia Tech School of Chemistry and Biochemistry. #

Details of the new staph infection detection method were published in the January issue of the journal Molecular⁸ and Cellular⁹ Proteomics. Partial funding for this research was provided by 3M and the CDC/Georgia Tech seed award program. #

Fernández together with Carrie Pierce, Jon Rees and John Barr from the CDC's Division of Laboratory Sciences created this test.

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"The simplicity¹⁰ of sample preparation, the low cost of required reagents（试剂） and the increased availability of mass spectrometers in clinical laboratories make this new method a cost-effective way to rapidly and effectively detect staph infections, which must be treated quickly to prevent spread of the disease," explained Pierce, a research chemist at the CDC who also worked on the project as a graduate student at Georgia Tech. #

To run their test, the researchers first inject a known amount of bacteriophage labeled with nitrogen-15 into a sample. The phages -- which are viruses that infect bacteria -- infect only live S. aureus cells, which then multiply and amplify¹¹ the phage signal. Following a two-hour incubation（孵化，潜伏） , the researchers break up proteins from the phage shell into component¹² peptides using a trypsin digest technique.