Open AccessVariable numbers of tandem repeat loci in genetically homogeneous Haemophilus influenzae strains alter during persistent colonisation of cystic fibrosis patients
Author(s) -
Renders Nicole,
Licciardello Lidia,
IJsseldijk Cathelijn,
Sijmons Marly,
Alphen Loek,
Verbrugh Henri,
Belkum Alex
Publication year - 1999
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1999.tb13489.x
Subject(s) - variable number tandem repeat , biology , haemophilus influenzae , genetics , tandem repeat , locus (genetics) , virulence , cystic fibrosis , southern blot , gene , genotype , bacteria , genome
Serial sputum isolates of Haemophilus influenzae ( n = 69 ) were obtained from eight patients suffering from cystic fibrosis. For two of these patients all strains were analysed for polymorphism in the major outer membrane protein profile. For all patients the strains were genetically characterised by random amplification of polymorphic DNA analysis. All strains were included in a survey for polymorphism in regions containing moieties of repetitive DNA as well. A single locus containing trinucleotide repeat units, three loci harbouring tetranucleotides, one region comprising pentanucleotide units and two hexanucleotide repeat unit‐containing loci were analysed for repeat number variability. Most of the regions were previously shown to be directly adjacent to or even within virulence genes. All regions behaved as genuine variable number of tandem repeat loci in the sense that genetic polymorphism based on the presence of varying numbers of repeat units could be demonstrated among different strains. Interestingly, several of the repeats showed variation in the absence of the variability as assessed by major outer membrane protein or random amplification of polymorphic DNA analysis. These observations indicate that the repeat loci may vary independently from major chromosomal polymorphism. Consequently, H. influenzae appears to modify its virulence gene regions of the chromosome during persistent colonisation of the lung in cystic fibrosis patients.