Toward an improved laboratory definition of Listeria monocytogenes virulence

Liu, Dongyou; Lawrence, Mark L.; Ainsworth, A. Jerald; Austin, Frank W.

doi:10.1016/j.ijfoodmicro.2007.07.045

Cited by 54 publications

(64 citation statements)

References 90 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The internalin genes inlC and inlJ, which are involved in passage through the intestinal barrier and the postintestinal stages of infection, performed well in discriminating strains that can or cannot cause mouse mortality via the intraperitoneal route (19). Although this does not automatically relate to the ability to produce disease in humans via the oral route, detection of the inlC and inlJ genes in all human isolates under study is an interesting preliminary finding that should be complemented by comparison with food and environmental isolates from the same geographic context.…”

Section: Discussionmentioning

confidence: 99%

“…However, because of the unique epidemiological and clinical characteristics of human foodborne listeriosis, traditional epidemiological surveillance systems alone are unable to detect most common-source outbreaks, particularly when a limited number of cases are scattered over a wide geographic area (25,26,29). Furthermore, when one is attempting to trace food exposures and transmission routes through food-processing chains, a further challenge is posed by the wide spectrum of L. monocytogenes strains, many of which are virulent and associated with significant morbidity and mortality while others are avirulent and unable to establish an infection in mammalian hosts (1,19). Consequently, rapid and discriminatory subtyping methods, such as various DNA-based methods, e.g., pulsed-field gel electrophoresis (PFGE), PCR and restriction fragment length polymorphism analysis, or sequencing of some specific se-quences, are essential for the epidemiological investigation of L. monocytogenes and the tracking of specific clones along food-processing chains (5,26,29).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Characterization of Listeria monocytogenes Isolates from Human Listeriosis Cases in Italy

Mammina¹,

Aléo²,

Romani

et al. 2009

J Clin Microbiol

View full text Add to dashboard Cite

The objective of this study was to characterize by serotyping, pulsed-field gel electrophoresis (PFGE), and PCR amplification of virulence genes and markers of epidemic clones I, II, and III (ECI, ECII, and ECIII) 54 human isolates from apparently sporadic cases of infection occurring in the Lombardy region and in the province of Florence, Tuscany, Italy, in the years 1996 to 2007. Listeria monocytogenes isolates were provided by the clinical microbiology laboratories of the Lombardy region and the "Careggi" Hospital of Florence, Tuscany, Italy. Serotyping, PFGE after digestion with the AscI and ApaI enzymes, and PCR amplification for the inlA, inlC, and inlJ genes and ECI, ECII, and ECIII markers were performed according to procedures described previously. Twenty-five (46.3%) L. monocytogenes isolates were assigned to serotype 1/2a, 23 (42.6%) to serotype 4b, and 6 (11.1%) to serotype 1/2b. Thirty-one AscI pulsotypes were recognized among the 54 human isolates. Eleven molecular subtype clusters, of which eight included indistinguishable pulsotypes and three included closely related pulsotypes, were shared by two to seven isolates. Fifteen isolates exhibited unique AscI pulsotypes. Three groups of clustered isolates and two apparently sporadic isolates generated EC amplicons. All strains tested positive for the inlA, inlC, and inlJ genes. Based on the results of serotyping and molecular typing, there were 11 occasions when L. monocytogenes strains with the same subtype were isolated from more than one listeriosis case. A total of 39 out of 54 isolates (72.2%) were attributed to molecular subtype clusters. The results of the study suggest that routine subtyping of L. monocytogenes strains from human listeriosis cases could allow more-timely detection of outbreaks possibly caused by food-borne isolates from a common source and could lead to control of ongoing food exposure, thus preventing the occurrence of more cases.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Characterization of Listeria monocytogenes Isolates from Human Listeriosis Cases in Italy

Mammina¹,

Aléo²,

Romani

et al. 2009

J Clin Microbiol

View full text Add to dashboard Cite

show abstract

“…A plaque forming assay was performed to determine the ability of 15 Listeria strains (1 each in lineages I and II, and 13 in lineage III) to spread from cell to cell as represented by plaque size (Liu et al, 2007). This assay was conducted in mouse fibroblasts L929 cells as previously described (Chen et al, 2009d).…”

mentioning

confidence: 99%

Deciphering the biodiversity of Listeria monocytogenes lineage III strains by polyphasic approaches

Zhao¹,

Chen²,

Fang³

et al. 2011

J Microbiol.

View full text Add to dashboard Cite

Listeria monocytogenes is a foodborne pathogen of humans and animals. The majority of human listeriosis cases are caused by strains of lineages I and II, while lineage III strains are rare and seldom implicated in human listeriosis. We revealed by 16S rRNA sequencing the special evolutionary status of L. monocytogenes lineage III, which falls between lineages I and II strains of L. monocytogenes and the non-pathogenic species L. innocua and L. marthii in the dendrogram. Thirteen lineage III strains were then characterized by polyphasic approaches. Biochemical reactions demonstrated 8 biotypes, internalin profiling identified 10 internal-in types clustered in 4 groups, and multilocus sequence typing differentiated 12 sequence types. These typing schemes show that lineage III strains represent the most diverse population of L. monocytogenes, and comprise at least four subpopulations IIIA-1, IIIA-2, HIB, and IIIC. The in vitro and in vivo virulence assessments showed that two lineage IIIA-2 strains had reduced pathogenicity, while the other lineage III strains had comparable virulence to lineages I and II. The HIB strains are phylogenetically distinct from other sub-populations, providing additional evidence that this sublineage represents a novel lineage. The two biochemical reactions L-rhamnose and L-lactate alkalinization, and 10 internalins were identified as potential markers for lineage III subpopulations. This study provides new insights into the biodiversity and population structure of lineage III strains, which are important for understanding the evolution of the L. mono-cytogenes-L. innocua clade.

show abstract

“…Briefly, female BALB/c mice at 20 g were allowed to acclimatize for 3 days, and inoculated intraperitoneally with appropriately 5 9 10 5 bacteria and sacrificed 3 days postinfection. Spleens and livers were homogenized in PBS (0.01 M, pH 7.2) and surviving cells enumerated by plating serial dilutions of the homogenized organs on BHI agar and incubating at 37°C for 24 h. Mice in the control group were injected with PBS (Liu et al 2007). …”

Section: Mouse Virulence Assaymentioning

confidence: 99%

Disruption of InlC2 enhances the internalization of Listeria monocytogenes by epithelial cells

Jiang

Chen

Cui

et al. 2011

World J Microbiol Biotechnol

View full text Add to dashboard Cite

The LPXTG internlin gene inlC2 is L. monocytogenes specific and formed an internalin cluster with inlD, inlE and, in some cases, inlG between ascB and dapE. Of note, inlC2 was transcribed monocistronically, and of these internalin genes, only inlC2 expression was enhanced in synthetic human gastric fluid. Disruption of inlC2 did not have a polar effect on its downstream internalin genes, but enhanced the production of InlA without changing inlA transcript level, suggesting a link between inlC2 expression and inlA posttranscriptional regulation. The adhesion and invasion rates of DinlC2 mutant in epithelial cells were significantly higher than those of parent strain. Also, recovery of listerial cells from the liver and spleen was much higher in mice inoculated with DinlC2 mutant than its parent strain. Thus, we speculate that increased invasion of DinlC2 mutant into epithelial cells might be due to elevated production of InlA, a major invasin, that could lead further to increased listerial virulence. Overall, this study presents supportive evidence that internalization of L. monocytogenes could be a complex network or unknown mechanisms requiring further study.

show abstract

Toward an improved laboratory definition of Listeria monocytogenes virulence

Cited by 54 publications

References 90 publications

Characterization of Listeria monocytogenes Isolates from Human Listeriosis Cases in Italy

Characterization of Listeria monocytogenes Isolates from Human Listeriosis Cases in Italy

Deciphering the biodiversity of Listeria monocytogenes lineage III strains by polyphasic approaches

Disruption of InlC2 enhances the internalization of Listeria monocytogenes by epithelial cells

Contact Info

Product

Resources

About