BACKGROUND & AIMS: Specific regions of the cag pathogenicity island (PAI) believed to enhance the virulence of Helicobacter pylori, as well as vacuolating cytotoxin gene alleles and IS605 inserts, were investigated to define diversity within infecting strain populations from patients with peptic ulcer disease and from healthy individuals. METHODS: The H. pylori studied comprised 67 isolates from 26 subjects and 14 reference strains. Specific polymerase chain reaction assays were used to test for cagA and picB in the cagI region, the virD4 homologue in the cagII region, IS605 in the genome and in the cag PAI, the "empty site" indicating absence of the cag PAI, and different vacA gene alleles. RESULTS: Most (89%) subjects were infected by H. pylori with a contiguous cag PAI. No intermediate forms were found. IS605 was not detected within the cag PAI of any strain but was present elsewhere in the genomes of strains from 62% of subjects. Twenty individuals were infected with genotypically conserved populations of H. pylori. Six subjects had mixed infections, and in 3 of these cag(+)/cag(-) variants were present. CONCLUSIONS: The cag PAI-positive H. pylori was a feature of most infected individuals, irrespective of severity of associated disease. Combined genotyping showed that 8 individuals (31%) had mixed infections, which suggests that strain population structure may be an additional contributing factor in disease development.
BACKGROUND & AIMS: Specific regions of the cag pathogenicity island (PAI) believed to enhance the virulence of Helicobacter pylori, as well as vacuolating cytotoxin gene alleles and IS605 inserts, were investigated to define diversity within infecting strain populations from patients with peptic ulcer disease and from healthy individuals. METHODS: The H. pylori studied comprised 67 isolates from 26 subjects and 14 reference strains. Specific polymerase chain reaction assays were used to test for cagA and picB in the cagI region, the virD4 homologue in the cagII region, IS605 in the genome and in the cag PAI, the "empty site" indicating absence of the cag PAI, and different vacA gene alleles. RESULTS: Most (89%) subjects were infected by H. pylori with a contiguous cag PAI. No intermediate forms were found. IS605 was not detected within the cag PAI of any strain but was present elsewhere in the genomes of strains from 62% of subjects. Twenty individuals were infected with genotypically conserved populations of H. pylori. Six subjects had mixed infections, and in 3 of these cag(+)/cag(-) variants were present. CONCLUSIONS: The cag PAI-positive H. pylori was a feature of most infected individuals, irrespective of severity of associated disease. Combined genotyping showed that 8 individuals (31%) had mixed infections, which suggests that strain population structure may be an additional contributing factor in disease development.
Authors: Rajashree Patra; Santanu Chattopadhyay; Ronita De; Simanti Datta; Abhijit Chowdhury; T Ramamurthy; G Balakrish Nair; Douglas E Berg; Asish K Mukhopadhyay Journal: Int J Med Microbiol Date: 2010-12-30 Impact factor: 3.473
Authors: Farhana Kauser; Aleem A Khan; M Abid Hussain; Ian M Carroll; Naheed Ahmad; Santosh Tiwari; Yogesh Shouche; Bimal Das; Mahfooz Alam; S Mahaboob Ali; C M Habibullah; Rafaela Sierra; Francis Megraud; Leonardo A Sechi; Niyaz Ahmed Journal: J Clin Microbiol Date: 2004-11 Impact factor: 5.948
Authors: Christina Nilsson; Anna Sillén; Lena Eriksson; Mona-Lisa Strand; Helena Enroth; Staffan Normark; Per Falk; Lars Engstrand Journal: Infect Immun Date: 2003-11 Impact factor: 3.441
Authors: Steffen Backert; Tobias Schwarz; Stephan Miehlke; Christian Kirsch; Christian Sommer; Terry Kwok; Markus Gerhard; Ulf B Goebel; Norbert Lehn; Wolfgang Koenig; Thomas F Meyer Journal: Infect Immun Date: 2004-02 Impact factor: 3.441