Pasteurized Milk as a Vehicle of Infection in an Outbreak of Listeriosis

Abstract

Between June 30th and August 30th, 1983, 49 patients in Massachusetts acquired listeriosis. Seven cases occurred in fetuses or infants and 42 in immunosuppressed adults; 14 patients (29 per cent) died. Of 40 Listeria monocytogenes isolates available for testing, 32 were serotype 4b. Two case-control studies, one matching for neighborhood of residence and the other for underlying disease, revealed that the illness was strongly associated with drinking a specific brand of pasteurized whole or 2 per cent milk (odds ratio = 9, P less than 0.01 for the neighborhood-matched study; odds ratio = 11.5, P less than 0.001 for the illness-matched study). The association with milk was further substantiated by four additional analyses that suggested the presence of a dose-response effect, demonstrated a protective effect of skim milk, associated cases with the same product in an independent study in another state, and linked a specific phage type with the disease associated with milk. The milk associated with disease came from a group of farms on which listeriosis in dairy cows was known to have occurred at the time of the outbreak. Multiple serotypes of L. monocytogenes were isolated from raw milk obtained from these farms after the outbreak. At the plant where the milk was processed, inspections revealed no evidence of improper pasteurization. These results support the hypothesis that human listeriosis can be a foodborne disease and raise questions about the ability of pasteurization to eradicate a large inoculum of L. monocytogenes from contaminated raw milk.

Quantification of Antibiotic Residues and Determination of Antimicrobial Resistance Profiles of Microorganisms Isolated from Bovine Milk in Lebanon

“…Another serious pathogen, L. monocytogenes, was also isolated from all collected milk samples. L. monocytogenes has been linked with numerous outbreaks associated with milk and milk products [39][40][41]. This pathogen may have contaminated the milk samples through inadequate sanitation during milking, storage and transport or from infected cows on the farms [42].…”

The inlA gene required for cell invasion is conserved and specific to Listeria monocytogenes

“…For each cloning, three clones were sequenced on both strands (Sanger e t al., 1977). INRA36 INRA49 INRA50 INRA64 INRA85 INRA35 INRA41 INRA6l NEM270 Madrid, Spain (Vicente et al, 1985) Trudeau Institute, New York (Gaillard et al, 1986) Los Angeles, USA, 1988 (Linnan et a[., 1988) 1 } Switzerland, 1990 (Bille, 1990) Nova Scotia, Canada, 1985 (Fleming et al, 1985) Angers, France, 1978 (Carbonnelle et al, 1978) these phylogenetically closely related species are likely to be derived from a common ancestor. This hypothesis implies that these sequences have sufficiently diverged from each other not to allow the detection of inlA-related sequences with our PCR assay.…”

Isolation of Listeria monocytogenes from the Skin of Slaughtered Beef Cattle

“…Listeriosis in human is both an invasive disease that manifests in various forms, such as encephalitis and meningitis neurological infections, abortion and septicemia, and a non-invasive gastrointestinal infection [13]. Listeriosis outbreaks have been reported in North America and Europe since the 1980s [2,5,12]. In Japan, a foodborne outbreak of listeriosis caused by contaminated cheese was first documented in 2001 [6].…”