Resistance to clarithromycin and genotypes in Helicobacter pylori strains isolated in Sicily

Abstract

The resistance of Helicobacter pylori strains to clarithromycin is increasing in several developed countries and their association with a genetic pattern circulation has been variously explained as related to different geographical areas. In this study we have reported: the prevalence of the resistance of H. pylori, isolated in Sicily, to clarithromycin; the principal point of mutation associated with this resistance; and the more frequent association between resistance to clarithromycin and cagA, the EPIYA motif, and the vacA and oipA genes. Resistance to clarithromycin was detected in 25 % of cases, the main genetic mutation involved being A2143G. The cagA gene was present in 48 % of cases and the distribution of the EPIYA motif was: ABC in 35 cases; ABCC in 8 cases; ABCCC in 2 cases; ABC-ABCC in 2 cases; and ABC-ABCC-ABCCC in 1 case. Regarding the vacA allele, an s1i1m1 combination was detected in 35 % of cases, s1i1m2 in 12 %, s1i2m2 in 12 %, s2i2m2 in 40 %, and a double s1m1-m2 mosaic in 1 % of cases. The status of the oipA gene was 'off' in 45 % of cases and 'on' in 55 %. Resistance to clarithromycin was found to be high in Sicily, but no correlation was found among resistance to clarithromycin, the vacA gene and oipA status; a higher correlation was observed between resistant strains and cagA-negative strains.

Eradication Rates in Italian Subjects Heterogeneously Managed for Helicobacter pylori Infection. Time to Abandon Empiric Treatments in Southern Europe

“…However, this drug became available in Italy only from March 2016, and data on its efficacy in southern Italy are still scarce. Our data confirm the high eradication rates with Pylera®, which seems able to overwhelm the limits linked to antibiotic resistance in the explored geographical area, characterized by a clarithromycin resistance rate higher than 15% [6,7,13,16,41].…”

“…However, as expected in an area where clarithromycin resistance is quite high -approximately 30% in Italy [6,13,16,41], and >15% in Apulia [7], the eradication rate was low and below what should be expected for an infectious disease [5,42]. In this respect, some additional considerations are required: i) the rising prevalence of clarithromycin-resistant H. pylori in southern Europe [41,43] and therefore in Italy [13], with regional differences [7], makes the PPI-clarithromycin-containing triple therapy unacceptable [5], at least in these geographical areas; ii) the duration of the PPI-clarithromycin-containing triple therapy was 7 days in our area, instead of 10 or 14 days, a policy aimed to further increase the success rate by another 4-5% [5] and possibly >80% [44,45] and, iii) the majority of PPI-clarithromycin-containing triple therapy used the PPI omeprazole 20 mg twice daily, instead of the more potent second-generation PPIs, i.e.…”

Protein signature characterizing Helicobacter pylori strains of patients with autoimmune atrophic gastritis, duodenal ulcer and gastric cancer

“…Strains were revitalized after a median of 9 months (range of 2–98 months) in H. pylori Selective Medium, expanded in Columbia sheep blood agar, and then used for proteome extraction. Bacterial DNA extraction and PCR on the virulence factor CagA gene were performed in H. pylori strains isolated from patients accordingly to Repetto et al [14] and Fasciana et al [15]. …”

Molecular Assessment of Resistance to Clarithromycin in Helicobacter pylori Strains Isolated from Patients with Dyspepsia by Fluorescent In Situ Hybridization in the Center of Iran

“…The breakpoint clarithromycin resistance was >0. 5 μg/mL [17]. MIC values were classified into low (MIC from >0.5 to ≤8 μg/mL) and high (MIC from >8 to 256 μg/mL) groups [18].…”