title: Primary clarithromycin resistance in Helicobacter pylori: the Multicentric Italian Clarithromycin Resistance Observational (MICRO) study.
abstract: BACKGROUND
  Primary clarithromycin resistance markedly reduces Helicobacter pylori eradication rate following standard therapies. Prevalence of primary clarithromycin resistance in H. pylori is increasing, and three point mutations are mainly involved. AIM. To assess both the prevalence of primary clarithromycin resistance in Italy, and the distribution of the involved point mutations.
  
  
  METHODS
  Primary clarithromycin resistance was assessed by TaqMan real-time polymerase chain reaction on antral biopsies of 253 consecutive, H. pylori infected patients enrolled in 13 Italian centres between January and September 2010.
  
  
  RESULTS
  Primary clarithromycin resistance was detected in 25 (9.9%) patients, with prevalence values widely ranging from 0 to 25%. Clarithromycin resistance rate was higher in female as compared to male patients (13.4% vs. 5.3%, p=0.03), and it tended to be higher in non-ulcer dyspepsia than in peptic ulcer patients (10.6% vs. 6.9%, p=0.5), female patients with non-ulcer dyspepsia showing the highest value (15.4%). The A2143G point mutation was detected in 13 (52.0%) patients, the A2142G in 9 (34.6%), whilst a double point mutation (A2143G plus A2142G) in 3 (11.6%) cases.
  
  
  CONCLUSIONS
  Primary clarithromycin resistance is highly variable in different Italian geographic areas. High resistance rates were observed in female and in dyspeptic patients. Among the three point mutations of clarithromycin resistance, the A2143G remains the most frequently observed.
authors.affiliation: Section of Gastroenterology, Department of Medical Sciences, University of Foggia, Ospedali Riuniti,Viale L. Pinto 71100, Foggia, Italy. vdefrancesco@ospedaliriunitifoggia.it
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Francesco
authors.forename: Floriana
authors.initials: F
authors.lastname: Giorgio
authors.forename: Enzo
authors.initials: E
authors.lastname: Ierardi
authors.forename: Mariangela
authors.initials: M
authors.lastname: Zotti
authors.forename: Matteo
authors.initials: M
authors.lastname: Neri
authors.forename: Angelo
authors.initials: A
authors.lastname: Milano
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Varasano
authors.forename: Francesco
authors.initials: F
authors.lastname: Luzza
authors.forename: Evelina
authors.initials: E
authors.lastname: Suraci
authors.forename: Riccardo
authors.initials: R
authors.lastname: Marmo
authors.forename: Armando
authors.initials: A
authors.lastname: Marone
authors.forename: Raffaele
authors.initials: R
authors.lastname: Manta
authors.forename: Vincenzo Giorgio
authors.initials: VG
authors.lastname: Mirante
authors.forename: Marina
authors.initials: M
authors.lastname: de Matthaeis
authors.forename: Antonietta
authors.initials: A
authors.lastname: Pedroni
authors.forename: Gianpiero
authors.initials: G
authors.lastname: Manes
authors.forename: Stefano
authors.initials: S
authors.lastname: Pallotta
authors.forename: Paolo
authors.initials: P
authors.lastname: Usai
authors.forename: Mauro
authors.initials: M
authors.lastname: Liggi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Gatto
authors.forename: Vittorio
authors.initials: V
authors.lastname: Peri
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Sacco
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Bresci
authors.forename: Fabio
authors.initials: F
authors.lastname: Monica
authors.forename: Cesare
authors.initials: C
authors.lastname: Hassan
authors.forename: Angelo
authors.initials: A
authors.lastname: Zullo
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017291:Clarithromycin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged
chemical_list: D000900:Anti-Bacterial Agents; D017291:Clarithromycin