title: Clinical relevance of cagA and vacA gene polymorphisms in Helicobacter pylori isolates from Senegalese patients.
abstract: The molecular epidemiology of Helicobacter pylori in Africa is poorly documented. From January 2007 to December 2008, we investigated 187 patients with gastric symptoms in one of the main tertiary hospitals in Dakar, Senegal. One hundred and seventeen patients were culture-positive for H. pylori. Polymorphisms in vacA and cagA status were investigated by PCR; the 3'-region of cagA was sequenced, and EPIYA motifs were identified. Bacterial heterogeneity within individuals was extensively assessed by using an approach based on vacA and cagA heterogeneity. Fourteen per cent of H. pylori-positive patients displayed evidence of mixed infection, which may affect disease outcome. Patients with multiple vacA alleles were excluded from subsequent analyses. Among the final study population of 105 patients, 29 had gastritis only, 61 had ulcerated lesions, and 15 had suspicion of neoplasia based on endoscopic findings. All cases of suspected neoplasia were histologically confirmed as gastric cancer (GC). The cagA gene was present in 73.3% of isolates. CagA proteins contained zero (3.7%), one (93.9%) or two (2.4%) EPIYA-C segments, and all were western CagA. Most of the isolates possessed presumed high-vacuolization isotypes (s1i1m1 (57.1%) or s1i1m2 (21.9%)). Despite the small number of cases, GC was associated with cagA (p 0.03), two EPIYA-C segments in the C-terminal region of CagA (p 0.03), and the s1 vacA allele (p 0.002). Multiple EPIYA-C segments were less frequent than reported in other countries, possibly contributing to the low incidence of GC in Senegal.
authors: Institut Pasteur, Unité de Biologie Médicale et Environnementale, Dakar, Senegal. sbreurec@pasteur.sn
authors: S
authors: S
authors: Breurec
authors: R
authors: R
authors: Michel
authors: A
authors: A
authors: Seck
authors: S
authors: S
authors: Brisse
authors: D
authors: D
authors: Côme
authors: F B
authors: FB
authors: Dieye
authors: B
authors: B
authors: Garin
authors: M
authors: M
authors: Huerre
authors: M
authors: M
authors: Mbengue
authors: C
authors: C
authors: Fall
authors: D N
authors: DN
authors: Sgouras
authors: J M
authors: JM
authors: Thiberge
authors: D
authors: D
authors: Dia
authors: J
authors: J
authors: Raymond
mesh_terms: D000293:Adolescent; D000328:Adult; D000349:Africa; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D060085:Coinfection / Q000382:microbiology / Q000473:pathology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005260:Female; D005756:Gastritis / Q000382:microbiology / Q000473:pathology; D005838:Genotype; D016481:Helicobacter Infections / Q000382:microbiology* / Q000473:pathology*; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010437:Peptic Ulcer / Q000382:microbiology / Q000473:pathology; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012675:Senegal; D017422:Sequence Analysis, DNA; D013274:Stomach Neoplasms / Q000382:microbiology / Q000473:pathology; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori