Analysis of sporadic cases of invasive listeriosis in a metropolis

Abstract

Introduction. Listeriosis is a foodborne infection, especially dangerous for people in at-risk groups. Susceptibility to listeria infection is determined by a complex of reasons: environmental factors, host immune status, and pathogen virulence. The susceptibility to listeriosis can also be aggravated by previous infections, especially viral infections, which demonstrate a steadily increasing number of identified pathogens.The aim of our study was to present molecular and genetic characterization of pathogens causing sporadic invasive listeriosis in a megalopolis, primarily during the peak of influenza and ARVI incidence.Materials and methods. Listeria monocytogenes isolates were collected from 18 hospitalized patients at hospitals in Moscow, from November 2018 to October 2019. The first comparison group was represented by isolates from food products and fish preserves. The second comparison group included previously examined environmental isolates. The clinical isolates were examined by using multilocus sequence typing techniques, including the standard MLST scheme extended by loci of internalin genes. Isolates of the autochthonous genotype (ST7) were compared through whole-genome sequencing and subsequent analysis of the core genome (cgMLST).Results. In cases of invasive listeriosis, 44% of isolates were isolated from patients with listeriosis; 27% of isolates were obtained from patients with meningitis. L. monocytogenes of phylogenetic lineage II prevailed in these groups of cases that occurred when the epidemic threshold for influenza was crossed during the 2018/2019 season. Listeria pneumonia identified in the senior age group occurred during the season of autumn ARVI and was primarily caused by L. monocytogenes of phylogenetic lineage I. The examination of genomes of ST7 isolates demonstrated identity between the core genomes of bacteria isolated from the mother-infant pair. Out of ST7 food isolates most closely related to the clinical ones was the isolate from meat (23 locus differences, the common deletion in the MFS transporter locus). Analyzing invasive listeriosis, the comparison between the list of the identified genotypes and the data from European countries showed that each country had its own specific range of genotypes, though ST7 was detected in all the examined samples.Conclusions. Along with the monitoring of food manufacturing and storage, timely vaccination against seasonal respiratory infections and use of personal protective equipment in public spaces can reduce the risk of listeriosis incidence in at-risk groups.

Diversity of Listeria monocytogenes Strains Isolated from Food Products in the Central European Part of Russia in 2000–2005 and 2019–2020

“…Comparison of the obtained results with isolates obtained from sporadic listeriosis cases in Moscow hospitals in 2018-2019 demonstrated a prevalence of lineage II strains (11 of 18 strains) among clinical isolates [37]. The ECVII (CC7) strains were the most frequent among human isolates obtained in Russia supporting the role of ECVII as a worldwide epidemic clone [22,38].…”

“…On the other hand, the increased world trade provides spreading of highly adaptive clones to the territories where they have been rare or not occurred before [25,27]. In Russia, the shift from phylogenetic lineage II to the phylogenetic lineage I was observed since the end of the XX century: while among strains associated with listeriosis in the second half of the 20th century almost 100% strains belonged to the lineage II, among human isolates of 2018-2020, the lineage II strains accounted for only 60% of human listeriosis [23,37].…”

Genetic Diversity of Listeria Detected in the Production Environment of Meat Processing

“…ST121 isolates are the most abundant in food products (meat, poultry, and fish), both according to our data for 2018–2019 [ 3 , 5 ] and according to the State Research Center for Applied Biotechnology and Microbiology in 2017 [ 16 ]. ST121 has not been found in other sources.…”

“…Analysis of these data and publications shows that ST8, which was predominant in the work environment in all sources considered (clinical human isolates, food and environmental isolates), did not occur prior to the COVID-19 pandemic. However, representatives of clonal complex 8 (CC8) differing from ST8 in one (SLV, single locus variant) or two (DLV, double locus variant) loci were noted in single cases in all sources: ST758, in the environment [ 8 ]; ST2096, in a clinical isolate in meningitis [ 3 ]; and ST16, in food products [ 16 ]. In December 2021–January 2022, four cases of invasive listeriosis caused by L. monocytogenes ST8 (ID 82490–82492, 82494) were noted in Moscow clinics.…”

“…Whole-genome sequencing of Listeria has become one of the tools in a polycentric study, which included the Gamaleya Research Institute of Epidemiology and Microbiology at the end of 2018 [ 3 ]. WGS supplemented the methods of MultiLocus Sequence Typing (MLST) and Multivirulentlocus Sequence Typing (MvLST), which determine the genotype (Sequence Type, ST) of Listeria and the profile of internalins (Internaline Profile, IP), proteins that ensure Listeria invasion into eukaryotic cells.…”