TABLE 3.

Distribution of virulence genes among the major genotypes during the in situ incubation of fresh fecal slurry in a commercial manure holding tank and in parallel laboratory microcosm incubations

Genotype	Virulence genotypea	Frequency (%) of carriage at the indicated wkb
		Wk 0 (n = 181)	Isolation chamber		Laboratory microcosm
			Wk 1 (n = 182)	Wk 7 (n = 105)	Wk 1 (n = 256)	Wk 7 (n = 214)
225	aida-I				0.5 ± 0.8	0.4 ± 0.7
	aida-I astA		0.5 ± 0.8
	astA		11.0 ± 0.0	5.0 ± 7.1		5.9 ± 2.4
	estB aida-I astA	1.2			0.9 ± 1.6
	estB fedA aida-I				0.5 ± 0.8
	fedA aida-I		3.8 ± 3.9		2.5 ± 1.6
	fedA aida-I astA	1.2	1.1 ± 1.6
	ND		57.7 ± 0.8	76.3 ± 9.0	11.2 ± 12.0	54.0 ± 21.1
276	estB fedA aida-I astA				0.5 ± 0.8
	fedA aida-I	77.9	5.5 ± 3.1		46.9 ± 36.7
	ND	0.6			0.5 ± 0.8
221	fedA aida-I				4.1 ± 4.0
	fedA aida-I astA	1.2
	ND		10.4 ± 0.8		8.1 ± 10.7
33	astA					0.9 ± 1.6
	ND					7.0 ± 12.2
285	estB fedA aida-I astA				0.5 ± 0.8
	fedA aida-I				0.5 ± 0.8
	ND	1.7		3.3 ± 4.7	1.7 ± 1.5	3.3 ± 5.8
51	fedA aida-I	1.7
	ND	4.7	1.1 ± 1.6			4.4 ± 4.2
224	fedA aida-I	4.7			0.4 ± 0.6
	ND	1.2	1.6 ± 0.8		0.4 ± 0.6
16	fedA aida-I	1.2			0.9 ± 1.6
	ND		0.5 ± 0.8		1.4 ± 2.4	1.5 ± 1.7
3	ND		0.5 ± 0.8	7.7 ± 3.3	0.5 ± 0.8	0.4 ± 0.7
248	aida-I					2.2 ± 3.8
	ND					2.6 ± 2.3

^aND, no virulence genes were detected.

^bResults represent data from two isolation chambers and three laboratory microcosm experiments. Data are from at least 1% of the total number of isolates of the experiment. Week 0 represents the initial inoculum. Values for weeks 1 and 7 are the averages ± standard deviations. Where no values are given, the frequency of this combination of virulence gene(s) and genotype was below the detection level. n, number of isolates.