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Comparison of listeriolysin O and phospholipases PlcA and PlcB activities, and initial intracellular growth capability among food and clinical strains of Listeria monocytogenes
Author(s) -
Kanki M.,
Naruse H.,
Kawatsu K.
Publication year - 2018
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.13692
Subject(s) - listeriolysin o , listeria monocytogenes , serotype , biology , microbiology and biotechnology , intracellular , vacuole , virulence , mutant , phagosome , bacteria , phagocytosis , listeria , genetics , gene , cytoplasm
Aims We investigated whether Listeria monocytogenes strains differ in their ability to escape from the primary phagosome after internalization into human intestinal epithelial cells. Methods and Results Food and clinical strains were used to study specific alleles; the activities of listeriolysin O ( LLO ) and phospholipases PlcA and PlcB, which promote rupture of the phagocytic vacuole; and initial intracellular bacterial growth in Caco‐2 cells. Results showed no difference in LLO activities between food and clinical strains or among serotypes. In contrast, the LLO truncation mutant lacked detectable haemolytic activity and intracellular growth. PlcA and PlcB produced by the strains of serotypes 4b/4e and 1/2b exhibited significantly lower activities than those of serotypes 1/2a and 1/2c. In contrast, the strains of serotype 1/2b grew significantly faster than those of serotypes 4b/4e and 1/2a. Moreover, the PrfA truncation mutants lacked LLO and phospholipases activities and did not show intracellular growth. Conclusions We determined that LLO and PrfA mutants exert a significant effect on intracellular growth, although it was unclear from this study whether PlcA and PlcB alleles affect escape from vacuoles. Significance and Impact of the Study This study estimates that low‐virulence L. monocytogenes strains associated with escape ability from the primary vacuoles are not widely distributed among food strains.