Evaluation of a matrix-assisted laser desorption ionization-time of flight mass spectrometry assisted, selective broth method to screen for vancomycin-resistant enterococci in patients at high risk

Tsi-Shu Huang; Susan Shin-Jung Lee; Chia-Chien Lee; Chiu-Yen Chen; Fang-Chen Chen; Bao-Chen Chen; Cheng Len Sy; Kuan-Sheng Wu

doi:10.1371/journal.pone.0179455

Evaluation of a matrix-assisted laser desorption ionization-time of flight mass spectrometry assisted, selective broth method to screen for vancomycin-resistant enterococci in patients at high risk

PLoS One. 2017 Jun 13;12(6):e0179455. doi: 10.1371/journal.pone.0179455. eCollection 2017.

Authors

Tsi-Shu Huang¹, Susan Shin-Jung Lee^{1

2

3}, Chia-Chien Lee¹, Chiu-Yen Chen⁴, Fang-Chen Chen^{4

5}, Bao-Chen Chen¹, Cheng Len Sy², Kuan-Sheng Wu^{2

3}

Affiliations

¹ Division of Microbiology, Department of pathology and laboratory medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
² Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
³ School of Medicine, National Yang-Ming University, Taipei, Taiwan.
⁴ Department of Nursing, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
⁵ Infection Control Unit, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.

Abstract

Background: Bile esculin azide with vancomycin (BEAV) medium is a sensitive, but slightly less specific method for vancomycin-resistant enterococci (VRE) screening. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a rapid method for identification of clinical pathogens. This study aimed to assess the performance of a novel combination screening test for VRE, using BEAV broth combined with MALDI-TOF MS.

Materials and methods: Clinical specimens were collected from patients at risk of VRE carriage, and tested by the novel combination method, using selective BEAV broth culture method followed by MALDI-TOF MS identification (SBEAVM). The reference method used for comparison was the ChromID VRE agar method.

Results: A total of 135 specimens were collected from 78 patients, and 63 specimens tested positive for VRE positive using the ChromID VRE method (positive rate 46.7%). The sensitivity, specificity, positive predictive value, and negative predictive value of SBEAVM method after an incubation period of 28 hours were 93.7%, 90.3%, 89.4%, and 94.2%, respectively. The SBEAVM method when compared to the ChromID VRE method had a shorter turnaround time (29 vs. 48-72 hours) and lower laboratory cost ($2.11 vs. $3.23 per test).

Conclusions: This study demonstrates that SBEAVM is a rapid, inexpensive, and accurate method for use in VRE screening.

Publication types

Evaluation Study

MeSH terms

Culture Media / chemistry
Gram-Positive Bacterial Infections / diagnosis*
Gram-Positive Bacterial Infections / microbiology
Humans
Mass Screening / methods
Mass Spectrometry / methods*
Reproducibility of Results
Sensitivity and Specificity
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods*
Vancomycin-Resistant Enterococci / isolation & purification*
Vancomycin-Resistant Enterococci / physiology

Substances

Culture Media

Grants and funding

This work was financially supported by Kaohsiung Veterans General Hospital (VGHKS104-102). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.