Allelic variation in internalin genes of Listeria monocytogenes isolated from humans, small rodents and mollusks

Abstract number: P1959

Zaytseva E., Ermolaeva S., Somov G.

L. monocytogenes is facultative intracellular pathogen, which causes an invasive disease with such severe symptoms as septicemia, meningitis, meningoencephalitis and stillbirths in human and animals. The surface and secreted proteins of the internalin family play a main role in L. monocytogenes invasion into eukaryotic cells. The structure of internalins includes LRR- (for leucine-rich repeat) domains. Among both eukaryotes and prokaryotes the LRR domains are involved in specific protein-protein interactions.

The purpose of this study is to analyze distribution of various internalin gene alleles among L. monocytogenes isolated from different sources and regions.

Methods: 50 and 17 L. monocytogenes isolates obtained in Far East and in European parts of Russia, respectively, were investigated. Four internalin genes – inlA, inlB, inlC, inlE, and the housekeeping gene prs, were partly sequenced. The study included three host specific groups of invasive isolates obtained from tissues of aborted fetuses (n = 19), small rodents (n = 13), marine organisms (n = 13). Control groups included isolates obtained from food (n = 22).

All isolates were divided into 32 sequence types (STs) according to results of sequencing. Geographic and host specific allelic variations in L. monocytogenes genes encoding invasion factors of the internalin family were revealed. The region specificity of STs to suggests the polyclonal distribution of L. monocytogenes strains in geographically distant regions. Some STs were isolated from particular hosts with high frequency although they were not host specific. There were ST1, ST6 and ST9 among isolates from aborted fetuses, ST1 among rodent isolates and ST17 among marine organism isolates.

The analysis of allelic variations in individual genes revealed a statistically relevant host specific prevalence of particular alleles for the following genes: inlA and inlC among aborted fetus isolates, inlB among rodent isolates, inlA, inlC, inlE among marine isolates. Alleles of all tested genes were distributed uniformly in control group. Alleles of the prs gene were distributed uniformly in all groups. Obtained results confirm with the knowledge on role of internalins in host specificity of L. monocytogenes.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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