Mucosal polymerase chain reaction for diagnosing Helicobacter pylori infection in patients with bleeding peptic ulcers

Table 1 Oligonucleotide primers used for cagA , vacA and iceA genotyping.

Region detected	Primer designation	Primer sequence	PCR product (bp)
s1 and s2	VA1-F	5’ATGGAAATACAACAAACACACC3'	259/286
	VA1-R	5’CTGCTTGAATGCGCCAAACTTTATC3'
s1a	SS1-F	5’GTCAGCATCACACCGCAAC3'	190
s1b	SS3-F	5’AGCGCCATACCGCAAGAG3'	187
s1c	S1C-F	5’CTYGCTTTAGTRGGGYTA-3'	213
m1	VA3-F	5’GGTCAAAATGCGGTCATGG3'	290
	VA3-R	5’CCATTGGTACCTGTAGAAAC3'
m1T	m1T-F	5’GGCCACAATGCAGTCATGG3'	290
	m1T-R	5’CTCTTAGTGCCTAAAGAAACA3'
m2	VA4-F	5’GGAGCCCCAGGAAACATTG3'	352
	VA4-R	5’CATAACTAGCGCCTTGCAC3'
iceA1	iceA1F	5’GTGTTTTTAACCAAAGTATC3'	247
	iceA1R	5’CTATAGCCASTYTCTTTGCA3'
iceA2	iceA2F	5’GTTGGGTATATCACAATTTAT3'	229
	iceA2R	5’TTRCCCTATTTTCTAGTAGGT3'
lcagA	lcagAD008	5’ATAATGCTAAATTAGACAACTTGAGCGA3'	297
	lcagAR008	5’TTAGAATAATCAACAAACATCACGCCAT3'

Table 2 Positive urease test, histology, bacterial culture and mucosal PCR in patients with bleeding and non-bleeding peptic ulcers.

	Bleeding peptic ulcers (n = 88, %)	Non-bleeding peptic ulcers (n = 81, %)	CG (n = 37, %)
Urease test	42/88 (48)	67/79 (85)	18/37 (49)
Histology	41/86 (48)	61/80 (76)	14/30 (47)
Culture	44/76 (58)	68/72 (94)	16/35 (46)
PCRb	54/88 (61)	70/81 (86)	20/37 (54)

^bP<0.001 between bleeding peptic ulcers and non-bleeding peptic ulcers, and between non-bleeding peptic ulcers and chronic gastritis (CG).

Table 3 Results of PCR test in patients with chronic gastritis, non-bleeding and bleeding peptic ulcers (PU).

Patients	PCR results	Hp (+)	Hp (-)	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	Accuracy (%)
Chronic gastritis	Positive	20	0	100	100	100	100	100
	Negative	0	17	(99.9-100.1)	(99.9-100.1)	(99.9-100.1)	(99.9-100.1)	(99.9-100.1)
Non-bleeding	PU Positive	70	1	99	90	99	90	98
	Negative	1	9	(98.9-99.1)	(89.9-90.1)	(98.9-99.1)	(89.9-90.1)	(97.9-98.1)
Bleeding PU	Positive	38	10	84b	77	79d	83a	81f
	Negative	7	33	(83.9-84.1)	(76.9-77.1)	(78.9-79.1)	(82.9-83.1)	(80.9-81.1)

^bP<0.001 vs non-bleeding, P = 0.02 vs chronic gastritis;

^dP<0.01 vs non-bleeding;

^fP = 0.001 vs chronic gastritis, P<0.001 vs non-bleeding;

^aP=0.02 vs chronic gastritis. Hp+: either positive H pylori culture or both positive rapid urease test and histology. PPV: positive predictive value, NPV: negative predictive value.