Distinguishing Clinical Enterococcus faecium Strains and Resistance to Vancomycin Using a Simple In-House Screening Test.

Natkamon Saenhom,Anusak Kerdsin,Rujirat Hatrongjit,Peechanika Chopjitt,Parichart Boueroy

doi:10.3390/antibiotics11030286

Natkamon Saenhom, Anusak Kerdsin + Show 3 more

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https://doi.org/10.3390/antibiotics11030286

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Abstract

Vancomycin-resistant enterococci (VRE) are a major concern as microorganisms with antimicrobial resistance and as a public health threat contributing significantly to morbidity, mortality, and socio-economic costs. Among VREs, vancomycin-resistant Enterococcus faecium (VREfm) is frequently isolated and is resistant to many antibiotics used to treat patients with hospital-acquired infection. Accurate and rapid detection of VREfm results in effective antimicrobial therapy, immediate patient isolation, dissemination control, and appropriate disinfection measures. An in-house VREfm screening broth was developed and compared to the broth microdilution method and multiplex polymerase chain reaction for the detection of 105 enterococci, including 81 VRE isolates (61 E. faecium, 5 E. faecalis, 10 E. gallinarum, and 5 E. casseliflavus). Verification of this screening broth on 61 VREfm, 20 other VRE, and 24 non-VRE revealed greater validity for VREfm detection. The accuracy of this broth was 100% in distinguishing E. faecium from other enterococcal species. Our test revealed 93.3% accuracy, 97.5% sensitivity, and 79.2% specificity compared with broth microdilution and PCR detecting van genes. The kappa statistic to test interrater reliability was 0.8, revealing substantial agreement for this screening test to the broth microdilution method. In addition, the in-house VREfm screening broth produced rapid positivity after at least 8 h of incubation. Application of this assay to screen VREfm should be useful in clinical laboratories and hospital infection control units.

Highlights

Enterococci are known as opportunistic pathogens and a leading cause of hospitalacquired infections, especially vancomycin-resistant enterococci (VRE) that are a major concern regarding their antimicrobial resistance as a public health issue
All tested enterococci were confirmed to the species level, van genes detected, and the minimal inhibitory concentration (MIC) values determined of vancomycin
The screening broth was evaluated using the broth microdilution method and PCR assay in terms of specificity, sensitivity, accuracy, and Cohen’s kappa coefficient

Summary

Introduction

Published: 22 February 2022Enterococci are known as opportunistic pathogens and a leading cause of hospitalacquired infections, especially vancomycin-resistant enterococci (VRE) that are a major concern regarding their antimicrobial resistance as a public health issue. The two major species that are well-known worldwide to cause human diseases and resistance to vancomycin are Enterococcus faecium and E. faecalis [1]. Of these two species, vancomycin-resistant E. faecium (VREfm) is more frequently isolated from patients with hospital-acquired infection than vancomycin-resistant E. faecalis and other species [1]. The World Health Organization (WHO) published their list of priority bacterial pathogens for which new antibiotics are urgently needed, and VREfm is listed in the high-priority category of antibiotic-resistant bacteria [2]. VREfm is widely distributed in hospitals around the world, with the prevalence varying according to geographical location. In European countries, VREfm has shown increasing prevalence, from 10% in 2015 to 17.3% in 2018 [3]

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