Outbreak investigation identifies a single Listeria monocytogenes strain in sheep with different clinical manifestations, soil and water.
Listeria (L.) monocytogenes causes orally acquired infections and is of major importance in ruminants. Little is known about L. monocytogenes transmission between farm environment and ruminants. In order to determine potential sources of infection, we investigated the distribution of L. monocytogenes genetic subtypes in a sheep farm during a listeriosis outbreak by applying four subtyping methods (MALDI-TOF-MS, MLST, MLVA and PFGE). L. monocytogenes was isolated from a lamb with septicemia and from the brainstem of three sheep with encephalitis. Samples from the farm environment were screened for the presence of L. monocytogenes during the listeriosis outbreak, four weeks and eight months after. L. monocytogenes was found only in soil and water tank swabs during the outbreak. Four weeks later, following thorough cleaning of the barn, as well as eight months later, L. monocytogenes was absent in environmental samples. All environmental and clinical L. monocytogenes isolates were found to be the same strain. Our results show that the outbreak involving two different clinical syndromes was caused by a single L. monocytogenes strain and that soil and water tanks were potential infection sources during this outbreak. However, silage cannot be completely ruled out as the bales fed prior to the outbreak were not available for analysis. Faeces samples were negative, suggesting that sheep did not act as amplification hosts contributing to environmental contamination. In conclusion, farm management appears to be a crucial factor for the limitation of a listeriosis outbreak.
Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, CH-3001, Switzerland; Graduate School for Cellular and Biomedical Sciences, Theodor Kocher Institute, University of Bern, CH-3012, Switzerland.
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Dreyer
Institute of Veterinary Bacteriology, Department of Infectious Diseases and Pathobiology, University of Bern, Bern, CH-3001, Switzerland.
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Thomann
Labor-Zentral, Geuensee, CH-6232, Switzerland.
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Böttcher
Institute of Veterinary Bacteriology, Department of Infectious Diseases and Pathobiology, University of Bern, Bern, CH-3001, Switzerland.
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Frey
Division of Neurological Sciences, Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, CH-3001, Switzerland. Electronic address: anna.oevermann@vetsuisse.unibe.ch.
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Oevermann
D000818:Animals; D015373:Bacterial Typing Techniques / Q000662:veterinary; D004196:Disease Outbreaks / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D005260:Female; D008089:Listeria monocytogenes / Q000235:genetics / Q000302:isolation & purification*; D008088:Listeriosis / Q000453:epidemiology / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D058885:Multilocus Sequence Typing / Q000662:veterinary; D018805:Sepsis; D012756:Sheep / Q000235:genetics; D012757:Sheep Diseases / Q000453:epidemiology* / Q000382:microbiology / Q000473:pathology; D012988:Soil Microbiology; D013557:Switzerland / Q000453:epidemiology; D014871:Water Microbiology
Livestock; Pathology; Rhombencephalitis; Septicemia; Subtyping