Treatment of Helicobacter pylori infection: Past, present and future

Table 1 Factors reported to negatively affect the outcome of therapies for Helicobacter pylori infection

Pathogen-related	Host-related
Development of resistance to antibiotics	Non-compliance to treatment
High bacterial load in the stomach	Non-ulcer dyspepsia
Protective effect of the gastric mucus layer	Smoking
Intracellular location of many bacteria	CYP2C19 status (rapid metabolizer)
CagA negative
Presence of dormant coccoid forms (not susceptible to antibiotics)
Heteroresistant status (co-existence of strains susceptible and resistant to the same antibiotic)

Table 2 Current regimens to treat Helicobacter pylori infection

Treatment	Regimen
Bismuth-containing quadruple therapy	A PPI (standard dose, bid), bismuth (standard dose, qid) tetracycline (500 mg, qid) and metronidazole (500 mg, qid) for 10-14 d
Sequential therapy	A 5-d dual therapy with a PPI (standard dose, bid) and amoxicillin (1 g, bid) followed by a 5-d triple therapy with a PPI (standard dose, bid), clarithromycin (500 mg, bid) and metronidazole (500 mg, bid)
Concomitant therapy	A PPI (standard dose, bid), clarithromycin (500 mg, bid), amoxicillin (1 g, bid) and metronidazole (500 mg, bid) for 7-10 d
Hybrid therapy	A 7-d dual therapy with a PPI (standard dose, bid) and amoxicillin (1 g, bid) followed by a 7-d quadruple therapy with a PPI (standard dose, bid), amoxicillin (1 g, bid), clarithromycin (500 mg, bid) and metronidazole (500 mg, bid)
Levofloxacin-based triple therapy	A PPI (standard dose, bid), levofloxacin (500 mg, bid) and amoxicillin (1 g, bid) for 10 d

PPI: Proton pump inhibitor.