title: Temporal Variation of Faecal Shedding ofEscherichia coli0157:H7 in A Dairy Herd Producing Raw Milk for Direct Human Consumption.
abstract: The objective of this study was to analyse over time the evolution ofE. coliO157:H7 faecal shedding in a dairy herd producing raw milk for direct human consumption. The study was performed between October 2012 and September 2013 in an average size Italian dairy farm where animals are housed inside the barn all over the year. The farm housed about 140 animals during the study - 70 cows and 70 calves and heifers. Twenty-six animals were randomly selected from both the cows and young animals group, and faecal sampling was performed rectally six times two months apart in each animal. Eleven animals were culled during the study and a total of 285 faecal samples were collected. At each faecal sampling, three trough water samples and two trough feed samples were also collected for a total of 36 water samples and 24 feed samples. Samples were analysed by real time polymerase chain reaction (RT-PCR) and culture. Overall, 16 (5.6%) faecal samples were positive forE. coliO157 by RT-PCR. Cultural examination found 9 (3.1%) samples positive forE. coliO157; all the isolates were positive forstx1,stx 2andeaegenes. One (4.1%) feed sample was positive forE. coliO157 by RT-PCR; none of the water samples was positive forE. coliO157. The model highlighted a general significant reduction of the number of positive samples observed during the study from the first to the sixth sampling (P=0.000) and a positive relation between the presence of positive samples and average environmental temperature (P=0.003). The results of the study showed that in an Italian dairy farm housing animals all year, faecal shedding ofE. coliO157 followed the same temporal trend reported for other types of farming. The enhanced faecal shedding during warmer months may have a significant impact on environmental contamination and the safety of raw milk and its byproducts.
authors: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna , Bologna.
authors: Giuseppe
authors: G
authors: Merialdi
authors: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna , Bologna.
authors: Lia
authors: L
authors: Bardasi
authors: Dipartimento di Scienze Mediche Veterinarie, Università di Bologna , Ozzano dell'Emilia (BO), Italy.
authors: Laura
authors: L
authors: Stancampiano
authors: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna , Bologna.
authors: Roberta
authors: R
authors: Taddei
authors: Dipartimento di Scienze Mediche Veterinarie, Università di Bologna , Ozzano dell'Emilia (BO), Italy.
authors: Mauro
authors: M
authors: Delogu
authors: Dipartimento di Scienze Mediche Veterinarie, Università di Bologna , Ozzano dell'Emilia (BO), Italy.
authors: Antonietta
authors: A
authors: Di Francesco
authors: Dipartimento di Scienze Mediche Veterinarie, Università di Bologna , Ozzano dell'Emilia (BO), Italy.
authors: Ilaria
authors: I
authors: Guarniero
authors: Dipartimento di Scienze Mediche Veterinarie, Università di Bologna , Ozzano dell'Emilia (BO), Italy.
authors: Ester
authors: E
authors: Grilli
authors: Dipartimento di Scienze Mediche Veterinarie, Università di Bologna , Ozzano dell'Emilia (BO), Italy.
authors: Mattia
authors: M
authors: Fustini
authors: Dipartimento di Scienze Mediche Veterinarie, Università di Bologna , Ozzano dell'Emilia (BO), Italy.
authors: Elena
authors: E
authors: Bonfante
authors: Dipartimento di Scienze Mediche Veterinarie, Università di Bologna , Ozzano dell'Emilia (BO), Italy.
authors: Federica
authors: F
authors: Giacometti
authors: Dipartimento di Scienze Mediche Veterinarie, Università di Bologna , Ozzano dell'Emilia (BO), Italy.
authors: Andrea
authors: A
authors: Serraino
keywords: Dairy farm; E. coli O157:H7; Raw milk