Ribotype diversity of Listeria monocytogenes strains associated with outbreaks of listeriosis in ruminants

Abstract

Ribotyping is a molecular method for the characterization, identification, and typing of bacterial isolates that has value in epidemiological studies. To demonstrate the utility of this technique for typing of Listeria monocytogenes, four outbreaks of epizootic listeriosis in ruminants were investigated through coordinated detection and characterization methods utilizing classical microbiology and nucleic acid-based techniques. L. monocytogenes strains isolated from clinical samples and the silage consumed by the affected animals were ribotyped to establish the causal relationship between feed and the disease outbreak. For all but one outbreak, we were able to isolate L. monocytogenes strains represented by the same ribotype from both clinical and silage samples. Additional L. monocytogenes strains with ribotypes different from those of the respective clinical samples were isolated from all silage samples. This indicates that a diverse population of L. monocytogenes strains exists in farm environments, of which some may be more likely than others to cause disease.

Manure and Microbes: Public and Animal Health Problem?

“…Listeria monocytogenes is such a bacterium. In addition, L. monocytogenes lives naturally in plant and soil environments, and poorly fermented silage often contains high numbers of L. monocytogenes (21,24,58). Outbreaks from raw vegetables that had been fertilized with sheep manure have been documented, as have infections associated with consumption of unpasteurized dairy products and with ice cream that had been infected during processing (23,38,55).…”

Outbreak of Clinical Listeriosis in Sheep: Evaluation from possible Contamination Routes from Feed to Raw Produce and Humans

“…Especially in sheep, listeriosis leads to head tilt and permanent circling movement (Radostits et al., 1999). A L. monocytogenes ‐associated epidemic in cattle and sheep leading extensively to abortion, septicaemia and central nervous symptoms have been rarely reported (Low and Renton, 1985; Wiedmann et al., 1996).…”

Typing ofListeria monocytogenesstrains isolated in Italy byinlA gene characterization and evaluation of a new cost-effective approach to antisera selection for serotyping

“…However, it has been observed that serotypes 1 ⁄ 2a, 1 ⁄ 2b, 1 ⁄ 2c and 4b are responsible for 95-98% of listeriosis cases (Liu 2006). Among these, serotype 4b strains are isolated mostly from epidemic outbreaks (Raybourne 2002;Borucki and Call 2003), whereas 1 ⁄ 2a, 1 ⁄ 2b and 1 ⁄ 2c are linked to sporadic infections and are the most prevalent serotypes in foods and food production environments (Wiedmann et al 1996). The conventional serological test has become widely used, because it is relatively convenient to perform, but lack of specificity and sensitivity and its low discriminatory ability do not always provide sufficient information in epidemiological investigations (Borucki and Call 2003;Doumith et al 2004).…”