title: Diversity of Listeria monocytogenes Strains of Clinical and Food Chain Origins in Belgium between 1985 and 2014.
abstract: Listeriosis is a rare but severe disease, mainly caused by Listeria monocytogenes. This study shows the results of the laboratory-based surveillance of Listeriosis in Belgium over the period 1985-2014. Besides the incidence and some demographic data we present also more detailed microbiological and molecular characteristics of human strains isolated since 2000. The strains from the latter period were compared to food and animal strains from the same period. Our study shows that different food matrices were commonly contaminated with L. monocytogenes presenting the same PFGE profile as in patient's isolates. Since 1985, we observed a significant decrease in incidence of the Materno-Neonatal cases (from 0.15 to 0.04 cases /100,000 inhabitants-year), which is probably to be attributed to active prevention campaigns targeting pregnant women. Despite the strengthening of different control measures by the food industry, the incidence of non-Materno-Neonatal listeriosis increased in Belgium (from 0.3 to 0.7 cases /100,000 inhabitants-year), probably due to the rise of highly susceptible patients in an aging population. This significant increase found in non-Materno-Neonatal cases (slope coefficient 7.42%/year, P<0.0001) can be attributed to significant increase in incidence of isolates belonging to serovars 1/2a (n = 393, slope coefficient 6.62%/year, P<0.0001). Although resistance to antimicrobials is rare among L. monocytogenes isolates, a trend to increasing MIC values is evident with chloramphenicol, amoxicillin, tetracycline and ciprofloxacin. We show that fluoroquinolone resistance is not linked to chromosomal mutations, but caused by a variety of efflux pumps. Our study also shows that huge majority of known underlying pathologies (426 out of 785 cases) were cancers (185/426, 43.1%) and haematological malignancies (75/185, 40.5%). Moreover the risk population is susceptible to low levels of contamination in food stressing the need of prevention campaigns specifically targeting these persons.
authors.affiliation: Section of Bacterial Diseases, NRC Listeria, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: S
authors.identifier: http://orcid.org/0000-0002-4170-5168
authors.initials: S
authors.lastname: Bertrand
authors.affiliation: Section of Bacterial Diseases, NRC Listeria, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: P J
authors.initials: PJ
authors.lastname: Ceyssens
authors.affiliation: Section of Bacterial Diseases, NRC Listeria, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Yde
authors.affiliation: Section of Foodborne Pathogens, NRL Listeria monocytogenes, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Dierick
authors.affiliation: Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Boyen
authors.affiliation: Medical Microbiology Laboratory, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Vanderpas
authors.affiliation: Section of Bacterial Diseases, NRC Listeria, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Vanhoof
authors.affiliation: Section of Bacterial Diseases, NRC Listeria, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: W
authors.initials: W
authors.lastname: Mattheus
mesh_terms: D000328:Adult; D000890:Anti-Infective Agents / Q000494:pharmacology; D001530:Belgium / Q000453:epidemiology; D004269:DNA, Bacterial; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D005260:Female; D020387:Food Chain; D005516:Food Microbiology; D005517:Foodborne Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D008089:Listeria monocytogenes / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008088:Listeriosis / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology; D008297:Male; D008826:Microbial Sensitivity Tests; D012703:Serotyping
chemical_list: D000890:Anti-Infective Agents; D004269:DNA, Bacterial