Table 1.
Recommended methods for the safety assessment of Enterococcus (non-QPS species).
| Tests | Methods | References |
|---|---|---|
| ANTIBIOTIC SUSCEPTIBILITY TESTS | ||
| Phenotypic antibiotic susceptibility: Ampicillin | Minimal inhibitory concentrations MICs (mg/L or μg/mL; Susceptibility Testing: EUCAST/ CLSI, ISO standard) | EFSA, 2012a |
| OTHER CONSIDERATIONS | ||
| Susceptibility to clinically relevant antibiotics (vancomycin, gentamicin, kanamycin, streptomycin, erythromycin, clindamycin, tetracycline, chloramphenicol) | Minimal inhibitory concentrations (MICs) (mg/L or μg/mL; Susceptibility Testing: EUCAST/ CLSI, ISO standard) | EFSA, 2012b; Laulund et al., 2017 |
| DETECTION OF VIRULENCE MARKERS ASSOCIATED WITH THE HOSPITAL STRAINS | ||
| IS16 | PCR | Werner et al., 2011 |
| esp | Hybridisation techniques | Hendrickx et al., 2007 |
| hylEfm | PCR | Rice et al., 2003 |
|
Alternative methods: -Hybridisation to colony lysates -Southern blots |
Singh et al., 1998 | |
| OTHER CONSIDERATIONS | ||
| *Genotypic assessment | - Multilocus sequence typing (MLST) - DNA fingerprint - PCR |
|
| Vancomycin operons (vanA, vanB, vanC, vanD, vanE, vanG, vanM, vanL, vanN) | Teo et al., 2011 | |
| Surface adhesin genes (efaAfs, efaAfm) | Eaton and Gasson, 2001 | |
| Cytolysin genes (cylLL, cylLs, cylM, cylB, cylA) | ||
| Aggregation protein gene (agg) | ||
| Extracellular metalloendopeptidase gelE | Nakayama et al., 2002 | |
| *Phenotypic assessment | ||
| Hemolytic Activity | Hemolytic activity assay on 5% sheep or horse blood Columbia agar plates | Semedo et al., 2003 |
| Gelatin hydrolysis | Assay for gelatinase activity on Todd-Hewitt (TH) agar plates containing 3% gelatin | Qin et al., 2000 |
| BIOGENIC AMINES DETECTION | ||
| - Histamine - Putrescine - Phenylethylamine - Cadaverine |
- High pressure liquid chromatography HPLC | EFSA Panel on Biological Hazards, 2011 |
|
Alternative methods (for Histamine) - Fluorometric methods - Immunoassays |
FDA, 2011 | |
| - Flow injection analysis | Hungerford et al., 2001 | |
| - Colorimetric method | Patange et al., 2005 | |
| Detection of amino acid decarboxylase-positive microorganisms | - Quantitative real-time PCR histamine-producing LAB - in vitro detection method (Enzymatic or chemical analysis) | Landete et al., 2007; EFSA Panel on Biological Hazards, 2011; FDA, 2011 |
| TOXIN PRODUCTION | ||
| - Cytotoxic potential | Vero cell cytotoxicity test | Laulund et al., 2017 |
| Full genome (When available) | NGS | EFSA, 2012a |