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Updated: Jan 23, 2026

Listeria monocytogenes Infection of the Brain
Published on: October 2, 2018
Identification of Listeria monocytogenes Based on the Detection of a 68-Kilodalton Cell-Surface Antigen
1Food Industry Research and Development Institute, P.O. Box 246, Hsinchu 300, Taiwan, Republic of China.
Abstract:
Conventional procedures for the detection of Listeria monocytogenes require selective enrichment and isolation, followed by several potentially lengthy identification steps. To facilitate the identification of the bacterium, polyclonal antibodies against a 68-kDa cell-surface antigen of L. monocytogenes were used to develop a sandwich enzyme-linked immunosorbent assay (ELISA). Of 51 strains of L. monocytogenes tested, 50 (98%) produced positive results using the ELISA method, whereas 17 non- Listeria strains yielded negative reactions. However, the polyclonal antibodies were found to cross-react with L. innocua and some strains of L. welshimeri . Further purification of the antibodies by affinity chromatography was impractical, since the increase in sensitivity was accompanied with decreased specificity. It is proposed that a combination of the ELISA with a single biochemical test, such as phosphoinositol-specific phospholipase C (PI-PLC), arylamidase, or hemolytic activity could differentiate L. monocytogenes (PI-PLC [+], hemolysin [+], arylamidase [-]) from L. innocua and L. welshimeri (PI-PLC [-], hemolysin [-], arylamidase [+]) , thus considerably reducing the number of steps required and the length of time necessary for the identification of L. monocytogenes .
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