Genomic changes during chronic Helicobacter pylori infection.
The gastric pathogen Helicobacter pylori shows tremendous genetic variability within human populations, both in gene content and at the sequence level. We investigated how this variability arises by comparing the genome content of 21 closely related pairs of isolates taken from the same patient at different time points. The comparisons were performed by hybridization with whole-genome DNA microarrays. All loci where microarrays indicated a genomic change were sequenced to confirm the events. The number of genomic changes was compared to the number of homologous replacement events without loss or gain of genes that we had previously determined by multilocus sequence analysis and mathematical modeling based on the sequence data. Our analysis showed that the great majority of genetic changes were due to homologous recombination, with 1/650 events leading to a net gain or loss of genes. These results suggest that adaptation of H. pylori to the host individual may principally occur through sequence changes rather than loss or gain of genes.
Kraft
Christian
C
Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
Stack
Allison
A
Josenhans
Christine
C
Niehus
Eike
E
Dietrich
Guido
G
Correa
Pelayo
P
Fox
James G
JG
Falush
Daniel
D
Suerbaum
Sebastian
S
D000328:Adult; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002908:Chronic Disease; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial; D044404:Genomic Islands / Q000235:genetics; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080866:cagA protein, Helicobacter pylori