Molecular and experimental virulence of Listeria monocytogenes strains isolated from cases with invasive listeriosis and febrile gastroenteritis.
We analyzed 27 Listeria monocytogenes strains of serotypes 1/2b and 4b, from invasive and gastroenteric listeriosis, for molecular and experimental virulence. Molecular virulence was tested by PCR for the presence of 8 major virulence-associated genes and genetic polymorphisms through restriction enzyme analysis; genomic DNA typing using pulsed-field gel electrophoresis was also performed. Experimental virulence was evaluated through intra-peritoneal and intra-gastric mouse virulence assays. Our results showed no significant differences in the virulence-related molecular properties of the strains analyzed. All strains were equally pathogenic following intra-peritoneal inoculation of mice. In mice inoculated intra-gastric with 4 representative strains of the 2 types of listeriosis, there were no significant differences in the bacterial count when comparing invasive and gastroenteric strains, suggesting that the strains were comparable in terms of mean oral infectivity.
Franciosa
Giovanna
G
National Center for Food Quality and Risk Assessment, Laboratory of Food Microbial Hazards, Istituto Superiore della Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
Maugliani
Antonella
A
Floridi
Francesca
F
Aureli
Paolo
P
D000818:Animals; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005759:Gastroenteritis / Q000382:microbiology*; D005798:Genes, Bacterial; D006801:Humans; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D008088:Listeriosis / Q000382:microbiology*; D051379:Mice; D008813:Mice, Inbred ICR; D012150:Polymorphism, Restriction Fragment Length; D014774:Virulence / Q000235:genetics
D004269:DNA, Bacterial