Characterization of Helicobacter felis by pulsed-field gel electrophoresis, plasmid profiling and ribotyping.
BACKGROUND
Helicobacter felis, an organism naturally infecting both canine and feline gastric mucosa, has been largely used as in animal models to study the ecology and treatment of human Helicobacter pylori infections. H. felis has not yet been studied at the genetic level.


METHODS
The aims of this study were to modify an in situ DNA isolation method suitable for H. felis and, by the use of pulsed-field gel electrophoresis (PFGE), plasmid profiling, and ribotyping, to determine the degree of genetic variation among H. felis strains isolated from cats and dogs from various geographic locations, and to determine the genome size of H. felis. Furthermore, the ability of these new H. felis strains to colonize mice was tested.


RESULTS
Most H. felis strains were distinguishable from each other, and 20 distinct PFGE types were detected. Four pairs of strains within a country and animal species produced identical patterns. All strains tested were found to carry several plasmids and plasmid profiling was equally discriminatory to PFGE. Ribotyping was not able to discriminate all the strains.


CONCLUSIONS
The genome size of H. felis was found to be approximately 1.6 Mb.
Jalava
K
K
Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, University of Helsinki, Finland. katri.jalava@helsinki.fi
De Ungria
M C
MC
O'Rourke
J
J
Lee
A
A
Hirvi
U
U
Hänninen
M L
ML
D000818:Animals; D002415:Cats; D004269:DNA, Bacterial / Q000032:analysis* / Q000378:metabolism; D004275:DNA, Ribosomal / Q000032:analysis* / Q000378:metabolism; D004285:Dogs; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D014644:Genetic Variation; D016680:Genome, Bacterial; D016998:Helicobacter / Q000737:chemistry / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D051379:Mice; D008807:Mice, Inbred BALB C / Q000382:microbiology; D008810:Mice, Inbred C57BL / Q000382:microbiology; D010957:Plasmids / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D015183:Restriction Mapping; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms
D004269:DNA, Bacterial; D004275:DNA, Ribosomal