cagA and vacA genotype of Helicobacter pylori associated with gastric diseases in Xi’an area

Table 1 Oligonucleotide primers used for vacA typing

Gene and region amplified	Genotype identified	Primer designation	Primer sequence	Size of PCR product(bp)
Mid-region	m1/m2	VAG-F	5’CAATCTGTCCAATCAAGCGAG3’	567/642
		VAG-R	5’GCGTCAAAATAATTCCAAGG3’
Signal sequence	s1/s2*	VA1-F	5’ATGGAAATACAACAAACACAC3’	259/286*
		VA1-R	5’CTGCTTGAATGCGCCAAAC3’
	s1a	SS1-F#	5’GTCAGCATCACACCGCAAC3’	190
	s1b	SS3-F#	5’AGCGCCATACCGCAAGAC3’	187

vacA types s1 and s2 were differentiated on the size of the PCR product. # Used with reverse primer VA1-R.

Table 2 The system of PCR

Constituents	Volume/per tube (μL)	Final concentration
Water	36
10×PCR buffer	5	1×
4dNTP, 2.5mmol/L /each	4	0.2mmol/L each
primer 1.25 μmol/L	1	0.5 μmol/L
primer 2.25 μmol/L	1	0.5 μmol/L
MgCl2, 50 mmol/L	1.5	1.5 mmol/L
Taq DNA polymerase, 5MU/L	0.5	0.1 MU/L
Template DNA	1

Table 3 H.pylori signal sequence typing and gastric diseases

s type	GC	CSG	CAG	GU	DU	Total(%)
s1a	43a	14	37	5	12	111 (57.8)
s1b	10	13	25	8	7	63 (32.8)
s2	3	4	7	3	1	18 (9.4)
Total	56	31	69	16	20	192 (100.0)

^aP < 0.05 vs GU, CSG, CAG.

Table 4 H.pylori signal sequence typing and gastric diseases

m type	GC	CSG	CAG	GU	DU	Total(%)
m1	31	13	36	7	12	99 (51.6)
m2	25	18	33	9	8	93 (48.4)
Total	56	31	69	16	20	192 (100.0)

No difference at all.

Table 5 Relationship between vacA typing and grade of vacu-olating cytotoxin activity

vacA type	Grade of vacuolating cytotoxin activity
	None	Low	High
s1a	5	38	68
s1b	17	24	22
s2	18	0	0
m1	10	30	59
m2	30	32	31

P < 0.05, each group vs s1a, s1b, s2.

Table 6 Relationship between vacA typing, cagA gene and gastric diseases for 192 H. pylori isolates

vacA type	cagA+					Total(%)
	GC	CSG	CAG	GU	DU
s1a	43	14	37	4	12	110 (66.7)
s1b	10	10	22	6	7	55 (33.3)
s2	0	0	0	0	0	0 (0.0)
m1	31	12	36	6	12	97 (58.8)
m2	22	12	23	4	7	78 (46.2)