J Vet Sci.  2020 Nov;21(6):e88. 10.4142/jvs.2020.21.e88.

Deletion of the oligopeptide transporter Lmo2193 decreases the virulence of Listeria monocytogenes

• Li H
• Qiao Y
• Du D
• Wang J
• Ma X

• KMID: 2509151
• DOI: http://doi.org/10.4142/jvs.2020.21.e88

Abstract

Background
Listeria monocytogenes is a gram-positive bacterium that causes listeriosis mainly in immunocompromised hosts. It can also cause foodborne outbreaks and has the ability to adapt to various environments. Peptide uptake in gram-positive bacteria is enabled by oligopeptide permeases (Opp) in a process that depends on ATP hydrolysis by OppD and F. Previously a putative protein Lmo2193 was predicted to be OppD, but little is known about the role of OppD in major processes of L. monocytogenes, such as growth, virulence, and biofilm formation.
Objectives
To determine whether the virulence traits of L. monocytogenes are related to OppD.
Methods
In this study, Lmo2193 gene deletion and complementation strains of L. monocytogenes were generated and compared with a wild-type strain for the following: adhesiveness, invasion ability, intracellular survival, proliferation, 50% lethal dose (LD₅₀) to mice, and the amount bacteria in the mouse liver, spleen, and brain.
Results
The results showed that virulence of the deletion strain was 1.34 and 0.5 orders of magnitude higher than that of the wild-type and complementation strains, respectively. The function of Lmo2193 was predicted and verified as OppD from the ATPase superfamily. Deletion of lmo2193 affected the normal growth of L. monocytogenes, reduced its virulence in cells and mice, and affected its ability to form biofilms.
Conclusions
Deletion of the oligopeptide transporter Lmo2193 decreases the virulence of L. monocytogenes. These effects may be related to OppD's function, which provides a new perspective on the regulation of oligopeptide transporters in L. monocytogenes.

Keyword

Listeria monocytogenes; oligopeptide permeases; gene deletion; biofilm; virulence