Internal Medicine: Open Access
Open Access

Comparison of sepsityper and in-house extraction methods for bacterial identification directly from positive blood culture bottles by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry

2^nd International Conference on Internal Medicine & Hospital Medicine

September 13-14, 2017 Dallas, USA

Chang Kyu Lee, Young Jin Ko and Yoonjung Cho

Korea University, South Korea

Posters & Accepted Abstracts: Intern Med

Abstract :

Rapid identification directly from blood culture bottles by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is known to shorten hospital stay and reduce hospitalization costs. We established an in-house extraction method for direct bacterial identification in a positively flagged blood culture bottle and compared the performance with sepsityper extraction method. We also analyzed the patterns of antibiotic prescription after reports of rapid identification result. The consecutive blood culture bottles were included in this prospective study at Anam Hospital, Korea University Medical Center from September 2016 to February 2017. All positively flagged blood culture specimens were prepared by in-house method and sepsityper kit (Bruker Daltonics, Bremen, Germany). The identification of the obtained pellet was carried out using a microflex MALDI-TOF MS (Bruker Daltonics, Bremen, Germany). The correct identification rates of each extraction method were compared according to the results of confirmation using MALDI-TOF MS and Vitek 2 (bioMerieux, France) system. Statistical analyses were performed using MedCalc for Windows, version 16.4.2 (MedCalc Software, Ostend, Belgium). A total of 173 bottles were registered in this study. Gram-negative bacilli were isolated from 76 specimens and Gram-positive bacteria were isolated from 97 specimens. The genus-/species-level identification rates of sepsityper and in-house method were 88.4/86.7% and 90.2/88.4%. In the case of Gram-negative bacilli, there was a statistically significant difference (82.9% vs. 93.4%) in the species-level identification rate (P=0.0459) between sepsityper and in-house method. In the case of Gram-positive bacteria, the species-level identification rates of sepsityper and in-house method were 89.7% and 84.5%, respectively (P=0.2812). In 89 cases (51.4%), there were no antibiotic changes. In 44 cases (25.4%), new antibiotics were added and in 10 cases (5.8%), empirical antibiotics were discontinued. In 23 cases (13.3%), antibiotics added after results of Gram stain were replaced with new antibiotics after reports of MALDI-TOF MS on the same day. Sepsityper and in-house extraction method showed excellent identification rates for rapid identification of bacteria directly from positive blood cultures by MALDI-TOF MS in this study. Rapid identification directly from the blood culture bottle was able to help clinicians to choose appropriate antibiotics.

Biography :

Chang Kyu Lee has completed his PhD from Korea University and Post-doctoral studies and Resident Program from Korea University School of Medicine. He is a Professor of the Department of Laboratory Medicine of Korea University School of Medicine. He has published more than 15 papers in reputed journals.