Primary clarithromycin resistance in Italy assessed on Helicobacter pylori DNA sequences by TaqMan real-time polymerase chain reaction

Background Helicobacter pylori clarithromycin resistance is increasing worldwide and different mutations are involved in its mechanisms. Recently, molecular methods have been proposed to assess these mutations. Aim To assess prevalence of primary clarithromycin resistance in two Italian areas, and the distribution of involved mutations, by using a novel method for real-time polymerase chain reaction. Methods Two hundred and thirty-two H. pylori-positive patients undergoing oesophagogastroduodenoscopy in two Italian towns (Rome, centre Italy; Foggia, south Italy) were enrolled. Helicobacter pylori infection was detected by histology, rapid urease and urea breath tests. Clarithromycin resistance was assessed by TaqMan real-time polymerase chain reaction on paraffin-embedded antral biopsies. Results Primary clarithromycin resistance was detected in 62 (26.7%) patients. Its prevalence did not differ between the two areas (31.5%, centre vs. 23.3%, south; P = 0.17) and between non-ulcer dyspepsia and peptic ulcer patients (28.4% vs. 20.7%, P = 0.2). The A2143G point mutation was detected in 35 (56.4%) patients, A2142G in 14 (22.6%), A2142C in eight (12.9%), whilst a double mutation (A2143G plus A2142C or A2142G) was present in the remaining five (8.1%) cases. Conclusions Our study found that primary clarithromycin resistance is highly prevalent in both central and southern Italy, and that A2143G is the most frequent point mutation involved in these areas.