an epidemiological study of listeriosis in dairy cattle

Bedding 1 4 6
Water 1 4 6
Feed 5 1
Maize silage 5 1
Water 2 5 1
Bedding 2 6 6
Bedding 3 6 7
Water 3 7 1
Grass silage 9 1
Animal 1 1 7
Animal 2 1 7
Animal 3 1 7
Animal 4 1 12
Farm E visit* RAPD
Animal 5 1 5
Animal 6 1 7
Animal 7 1 7
Animal 8 1 7
Animal 9 2 12
Animal 10 2 7
Animal 11 3 1
Animal 12 3 1
Animal 13 3 7
Animal 14 3 7
Animal 15 5 6
Animal 16 5 5
Animal 17 5 5
Animal 18 5 1
Animal 19 5 5
* visit on which isolate was made from the environment and faeces, @ Figure 6. 11, # Figure 6. 12a and
12b.
A total of 113 isolates of L. monocytogenes (40 environmental and 73 faecal
isolates) were examined (Table 6. 18). 12 distinct patterns were obtained. 9 different
patterns were detected in environmental isolates and 9 in faecal isolates. 6 patterns were
common to both.
Patterns 1, 5, 6 and 7 were sequentially the most commonly identified in both
samples (Table 6. 19). Patterns 10, 11 and 12 were not detected in environmental
isolates and patterns 4, 8 and 9 were not detected in faecal isolates.
On farms, a maximum 4 environmental patterns and 6 faecal patterns were
identified. Pattern 1 was the most common in environmental (30%) and faecal isolates
(34%). It shared this proportion with pattern 5 in environmental samples (30%). There
were differences between the farms. Pattern 1 was most frequent on farms C and D. The
predominant patterns on farms A, B and E were different. On farm A pattern 5 was most
common, on farm B pattern 6 and 1 were present in similar proportions and on farm E
pattern 7 was predominant (Table 6. 19).
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