Ann Clin Microbiol.  2024 Dec;27(4):267-270. 10.5145/ACM.2024.27.4.6.

Risk of inaccurate species identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and of false carbapenem resistance by automated susceptibility analysis of Enterobacter spp.

• Kim YA

• KMID: 2566092
• DOI: http://doi.org/10.5145/ACM.2024.27.4.6

Abstract

Enterobacter species were isolated from the sputum of an 84-year-old female patient with fever, chills, cellulitis in the right elbow, and pyogenic arthritis in the left shoulder. The bacteria were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and whole-genome sequencing (WGS). This strain was defined as a carbapenem-resistant Enterobacterales (CRE) by the MicroScan NG MIC 44 panel without applying the revised guidelines of the Korea Disease Control and Prevention Agency properly. MALDI-TOF MS is commonly used to determine species, but the accurate identification of Enterobacter subspecies remains challenging. An Etest or disk diffusion test is recommended to confirm ertapenem resistance when an isolate exhibits resistance solely to ertapenem among carbapenems.

Keyword

Carbapenems; Drug resistance; Enterobacter; Matrix-assisted laser desorptionionization mass spectrometry

Reference

1. Mezzatesta ML, Gona F, Stefani S. Enterobacter cloacae complex: clinical impact and emerging antibiotic resistance. Future Microbiol 2012;7:887–902.

2. De Oliveira DMP, Forde BM, Kidd TJ, Harris PNA, Schembri MA, Beatson SA, et al. Antimicrobial resistance in ESKAPE pathogens. Clin Microbiol Rev 2020;33:e00181-19.

3. Tsuchida S, Umemura H, Nakayama T. Current status of matrix-assisted laser desorption/ ionization-time-of-flight mass spectrometry (MALDI-TOF MS) in clinical diagnostic microbiology. Molecules 2020;25:4775.

4. Pavlovic M, Konrad R, Iwobi AN, Sing A, Busch U, Huber I. A dual approach employing MALDI-TOF MS and real-time PCR for fast species identification within the Enterobacter cloacae complex. FEMS Microbiol Lett 2012;328:46-53.

5. Heo J, Choi YJ, Kim YA, Jeong SH, Shin JH, Shin KS, et al. Current prevalence of the crpP gene in carbapenemase-producing Pseudomonas aeruginosa blood isolates in Korea. Ann Clin Microbiol 2022:25;53-9.

6. Center for Genomic Epidemiology. https://www.genomicepidemiology.org/ [Online] (last visited on 2 April 2024).

7. Lee M and Chung HS. Different antimicrobial susceptibility testing methods to detect ertapenem resistance in Enterobacteriaceae: VITEK2, MicroScan, Etest, disk diffusion, and broth microdilution. J Microbiol Methods 2015;112:87-91.

8. Davin-Regli A, Lavigne JP, Pagès JM. Enterobacter spp.: update on taxonomy, clinical aspects, and emerging antimicrobial resistance. Clin Microbiol Rev 2019;32:e00002-19.

9. Doijad S, Imirzalioglu C, Yao Y, Pati NB, Falgenhauer L, Hain T, et al. Enterobacter bugandensis sp. nov., isolated from neonatal blood. Int J Syst Evol Microbiol 2016;66:968–74.

10. Li X, Jiang T, Wu C, Kong Y, Ma Y, Wu J, et al. Molecular epidemiology and genomic characterization of a plasmid-mediated mcr-10 and bla_NDM-1 co-harboring multidrugresistant Enterobacter asburiae. Comput Struct Biotechnol J 2023;21:3885-93.

11. Korea Disease Control and Prevention Agency. 2019 Medical Infectious Disease (VRSA.CRE) Management Guidelines. https://www.kdca.go.kr/board/board. es?mid=a20507020000&bid=0019&act=view&list_no=364862 [Online] (last visited on 19 Nov 2024).

12. CLSI. Performance standards for antimicrobial susceptibility testing, supplement M100. 32nd ed. Wayne, PA; Clinical and Laboratory Standards Institute: 2022.