Virulence of water-induced coccoid Helicobacter pylori and its experimental infection in mice

Table 1 Urease activity of H.pylori

Strain	Urease activity
	Spiral form	Coccoid form
F44	++++	+
F45	++++	++
F49	++++	+

Table 2 Adherence of H.pylori to Hep-2 cells

	Adherence rate (%)a			Adherence indexb(Bacteria numbers per cell)
	F44	F45	F49	F44	F45	F49
Spiral form	70.0 ± 5.3	73.0 ± 5.1	72.6 ± 4.5	2.6 ± 0.4	3.1 ± 0.5	2.9 ± 0.4
Coccoid form	30.2 ± 3.5	35.7 ± 4.1	31.4 ± 4.0	0.86 ± 0.3	0.91 ± 0.3	0.88 ± 0.4
t value	12.3	11.2	12.8	7.2	7.8	7.4
P	< 0.01	< 0.01	< 0.01	< 0.01	< 0.01	< 0.01

^aAdherence rate = amount of cells adhered by bacteria/ 100 × 100%;

^bAdherence index = total amount of bacteria adher-ing to 100 cells/100; Five groups of 100 cells on the same cov-erslip were counted for the bacteria adhered. Data are presented as mean ± SD. t and P values were obtained using Student t test.

Table 3 Tests of bacteria in gastric mucosa samples

Group	Total no.	Fast urease test			Culture of bacterial
		Positive/total		Positive rate(%)	Positive/total		Positive rate(%)
		D21	D28		D21	D28
1	16	7/8	8/8	93.8	7/8	7/8	87.5
2	16	4/8	4/8	50.0	5/8	6/8	68.8
Control	10	0/5	0/5	0	0/5	0/5	0

Group 1 was inoculated with spiral H. pylori, group 2 was in-oculated with water-induced coccoid H. pylori, and control group received sterile tap water.

Table 4 Scores for urease tests of tissue samples

Groups	Color development				Urease activity(mean score)
	-	+	++	+++
1	1a	5	7	3	1.75b
2	8	7	1	0	0.56
Control	10	0	0	0	0

^aNumbers of mice;

^bRefers to text for scoring and calculation.

Table 5 Pathogogical alterations of gastric mucosa from mice

Groupe	Histopathological event (no. of mice)
	Normal	Gentle erosion	Deep erosion	Ulcer	Total
1	1	7	6	2	16
2	6	9	1	0	16
Control	10	0	0	0	10