The effect of CagA status on response to Helicobacter pylori eradication therapy in Western Turkey

Abstract

If cytotoxin-associated gene A (CagA) status affects the response rates of therapy, then it may be possible to predict Helicobacter pylori eradication rates. We aimed to evaluate the response to eradication treatment of H. pylori infection in CagA-positive and CagA-negative patients. A total of 184 patients (93 males, 91 females, mean age 42.6 ± 12.8 years) with H. pylori-positive chronic gastritis were studied. Subjects underwent a gastroscopy and biopsy specimens were taken from the gastric antrum, body, and fundus. Before the eradication therapy was given all patients were tested for CagA, TNF-= and gastrin levels. They were then prescribed lansoprazole (30 mg bid), clarithromycin (500 mg bid), and amoxicillin (1.0 mg bid) for one week. On the 8th week a second endoscopy was performed and further biopsy specimens were obtained from the same sites as in the initial endoscopy. One hundred and twenty-seven patients (69.1%) were found to be CagA positive and 57 patients (30.9%) were CagA negative. The total eradication rate was 82.6%. In the CagA-positive group this rate was 87.4%, and in the CagA-negative group it was 71.9% (P = 0.019). TNF-= levels were higher in the CagA-positive than in the CagA-negative group (P = 0.001). However, gastrin levels were not different between groups (P = 0.421). Our findings revealed that CagA-negative status might be a risk factor for failure of H. pylori triple therapies. The CagA pathogenicity island gives a growth advantage to H. pylori strains and has been associated with an increase in the inflammatory response at the gastric mucosal level. These properties could make CagA-positive H. pylori strains more susceptible to antibiotics.

Analysis of drug resistance and virulence‐factor genotype of Irish Helicobacter pylori strains: is there any relationship between resistance to metronidazole and cagA status?

“…The acquisition of MTZ resistance occurred with higher frequency in cagA ‐negative strains than in cagA ‐positive strains and there is a possible relationship between absence of cagA and spontaneous MTZ resistance (Table 3). The relationship between cagA ‐positive status and successful treatment with antibiotics was reported previously 38–41 . They indicated that in infected patients, the cagA ‐positive strain seemed to be more easily eradicated using antibiotics than in those with cagA ‐negative strains.…”

Relationship Between Drug Resistance and cagA Gene in Helicobacter pylori

“…Similarly, some studies also failed to find any general association between virulence markers and antibiotic resistance (18,22,37). This result is inconsistent with other studies that suggesting the statistically relation between drug resistance and cagA-positive strains (27,31,38,39). There is little information about the relation between the variability of the strain and any outcome on the drug resistance rates of H. pylori.…”

The efficacy, safety and tolerability of pantoprazole-based one-week triple therapy in H. pylori eradication and duodenal ulcer healing

“…In Turkey, the efficacy of two other PPI containing regimens, namely omeprazole and lansoprazole-based therapies, in the eradication of H. pylori has been investigated in several studies [9][10][11] . A gradual decrease in success rates of these eradication regimens has been observed in some recent regional studies conducted in Turkey, and there are possible explanations for the observed loss of efficacy [12][13][14] .…”