Rapid identification of pathogenic organisms positive for blood culture by MALDI-TOF mass spectrometry in combination with Sepsityper Kit or serum-separating gel tubes
Objective 
To evaluate the feasibility of using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in combination with Sepsityper Kit or serum-separating gel tubes for identification of pathogenic organisms positive for blood culture. 
 
 
Methods 
A total of 153 clinical specimens with a positive result in blood culture were collected and tested with MALDI-TOF MS in combination with Sepsityper Kit or serum-separating gel tubes. Test results were compared with those by using culturing. 
 
 
Results 
The 153 positive blood culture specimens included 143 of single bacterial infection and 10 of multiple bacterial infections. The consistency rates at species and genus levels were 76.2% (109/153) and 7.8% (12/153) between Vitek 2 Compact method and MALDI-TOF MS combined with Sepsityper Kit, and 75.1% (101/153) and 8.5% (13/153) between Vitek 2 Compact method and MALDI-TOF MS combined with serum-separating gel tubes. In the identification of single bacterial infection specimens, the consistency rates of MALDI-TOF MS combined with Sepsityper Kit at species and genus levels were 95.2% (79/83) and 0% (0/83) for gram-negative bacteria, 57.5% (27/47) and 23.4% (11/47) for gram-positive bacteria and 33.3% (3/9) and 11.1% (1/9) for Candida, the consistency rates of MALDI-TOF MS combined with serum-separating gel tubes at species and genus levels were 90.4% (75/83) and 4.8% (4/83) for gram-negative bacteria, 55.3% (26/47) and 14.9% (7/47) for gram-positive bacteria and 0% (0/9) and 22.2% (2/9) for Candida. MALDI-TOF MS combined with Sepsityper Kit was only consistent with Vitek 2 Compact method in the identification of one specimen of multiple bacterial infections. 
 
 
Conclusion 
MALDI-TOF MS in combination with Sepsityper Kit or serum-separating gel tubes can identify the pathogens positive for blood culture within one hour and is of high consistency with culturing. In comparison with the traditional identification method for positive blood cultures, MALDI-TOF MS combined with Sepsityper Kit or serum-separating gel tubes has the advantages of rapidity and easy operation, which meet the clinical needs of rapid diagnosis and timely and effective antibacterial treatment, and is of great value in clinical application. 
 
 
Key words: 
Sepsityper Kit; Serum-separating gel tube; MALDI-TOF MS; Blood culture