Antimicrobial susceptibility testing for Helicobacter pylori in times of increasing antibiotic resistance

Table 1 Proposed clinical antimicrobial breakpoints for Helicobacter pylori

Antibiotic	Susceptible (mg/L)	Resistant (mg/L)
Amoxicillin	≤ 0.12	> 0.12
Clarithromycin	≤ 0.25	> 0.5
Metronidazole	≤ 8	> 8
Levofloxacin	≤ 1	> 1
Rifampicin1	≤ 1	> 1
Tetracycline	≤ 1	> 1

¹Although rifabutin is used clinically, rifabutin E tests are not available routinely and rifampicin is used to screen for rifabutin resistance. Adapted from European Committee on Antimicrobial Susceptibility Testing[48].

Table 2 Sensitivity and specificity of molecular tests for detecting Helicobacter pylori antibiotic resistance

Molecular test	Antibiotic	Sensitivity	Specificity	Ref.
PCR	Clarithromycin	82%	100%	[64]
Genotype HelicoDR assay	Clarithromycin	94%	99%	[57]
	Levofloxacin	87%	98.5%
PCR	Clarithromycin	90.6%	95.8%	[59]
PCR	Clarithromycin	89.2%	100%	[62]
Genotype HelicoDR assay	Clarithromycin	100%	86.2%	[72]
	Levofloxacin	82.6%	95.1%
PCR	Clarithromycin	83.3%	100%	[65]

PCR: Polymerase chain reaction.

Table 3 Summary of Europe-wide studies on antibiotic resistance rates over time

Antibiotic	1991[93]	1998[74]	2008/9[42]
Metronidazole	27.5%	33.1%	34.9%
Clarithromycin	ND	9.9%	17.5%
Amoxicillin	ND	0.8%	0.7%
Levofloxacin	ND	ND	14.1%
Tetracycline	ND	ND	0.9%
Rifampicin	ND	ND	1.1%

ND: No data.

Table 4 Recent data on Helicobacter pylori antibiotic resistance rates in different regions and countries

Ref.	Region	Antibiotic resistance rates
		Clar	Met	Levo
Tveit et al[94]	Alaska	30%2	42%2	19%2
Gao et al[71]	China; Beijing	37.2%2	63.9%2	50.3%2
Su et al[83]	China; South East coastal region	21.5%2	95.4%2	20.6%2
McNulty et al[19]	England	3%2	22%2	1%2
Megraud et al[42]	Europe; Northern countries	7.7%1	28.6%1	7.7%1
Megraud et al[42]	Europe; Southern countries	21.5%1	29.7%1	13.1%1
Megraud et al[42]	Europe; Western and central countries	18.7%1	43.8%1	18.6%1
Abadi et al[95]	Iran	45.2%2	65.5%2	34.5%2
O’Connor et al[81]	Ireland	9.3%1	29.1%1	ND
O’Connor et al[82]		13.2%2	31.5%2	11.7%2
Yamade et al[84]	Japan	38.8%1	ND	34%1
		55.6%2	ND	38.6%2
Lee et al[85]	Korea	23.7%1	ND	28.1%1
Seck et al[96]	Senegal	1%1	85%1	15%1
Vilachione et al[70]	Thailand	3.7%1	36%1	7.2%1
McNulty et al[19]	Wales	18%2	43%2	13%2

¹Primary antibiotic resistance rates;

²Overall resistance rates. Clar: Clarithromycin; Met: Metronidazole; Levo: Levofloxacin; ND: No data presented in this study.