MSACL 2019 EU Abstract

Detection of Carbapenemase-producing Organisms via MALDI-TOF

Narae Hwang1,2, Yu Kyung Kim1,2, Kyung Eun Song1,3
(1) Department of Clinical Pathology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea (2) Department of Laboratory Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea (3) Department of Laboratory Medicine, Chilgok Kyungpook National University Hospital, Daegu, Republic of Korea

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Narae Hwang (Presenter) Kyungpook National University >> POSTER (PDF)

Relevant Financial Disclosures (within past 24 months) No relevant financial relationship(s) to disclose. Conflict mitigation NOT REQUIRED.

INTRODUCTION:
Carbapenem antibiotics have been considered to be the last resort for the treatment of life threatening infections. Carbapenemases are enzymes which inhibit most β-lactam antibiotics, including carbapenems and they have been reported in Enterobacteriaceae, P. aeruginosa, and others. The emergence of carbapenem-resistant enterobacteriaceae(CRE) poses major threat to public health. Among carbapenem-resistant enterobacteriaceae, some of them carry resistance determinants in motile genetic elements and they are capable of transferring the resistance to other microorganisms. Hence, they are called carbapenemase-producing enterobacteriaceae(CPE) .
When CRE is detected from a patient, it is important to rapidly detect whether the resistant orgranism can be spread to others. Recently, MALDI-TOF MS has been adopted as a universal tool for the identification of microorganism and several attempts have been made to use this technology beyond the identification to more complicated characterization of microorganism.
In this study, we used a MALDI-TOF MS based approach for the detection of specific peak which can be helpful for the differentiation of CPE from other CRE.
METHODS:
The cohort was composed of 51 CRE clinical isolates collected from patients between December 2016 and October 2018 at the Kyungpook National University Hospital. Among the clinical isolates, 39 samples had CPE mobile elements which were confirmed by PCR. Among those, four samples had NDM-5 and 29 samples had both NDM-5 and OXA-181. Proteins were obtained with the tube extraction method and MALDI-TOF MS spectra were obtained. Using MALDIquant R program, mass spectra were analyzed to find any peak difference between CPE negative microorganism and CPE positive microorganism.
RESULTS:
When control samples(ATCC E. coli) and NDM5 CPE samples were compared, m/z  9744.45 Da were found to be the most differentiating peak. When control samples(ATCC E.coli) and CPE which has NDM 5 and OXA181 compared, m/z  3022.34 Da were found to be the most differentiating peak. Further study for the confirmation of the peaks is in need.

CONCLUSION:
Application of MALDI-TOF MS for the rapid detection of CPE is a cheap, reliable, and clinically useful method and will be very helpful for prompt control of infections caused by CRE.