DNA‐DNA hybridization and analysis of restriction endonuclease and rRNA gene patterns of atypical (catalase‐weak/negative) Campylobacter jejuni from paediatric blood and faecal cultures

Abstract

Sixteen strains of atypical (catalase-weak or negative), hippurate-hydrolysing campylobacters from paediatric blood and faecal cultures were identified by DNA-DNA slot hybridization. All were closely related (greater than or equal to 67%) to Campylobacter jejuni and representative strains had G + C contents of 30 +/- 1 mol%. Numerical analysis of chromosomal DNA HaeIII digest patterns revealed two clusters of strains at the 55%S level corresponding to C. jejuni subsp. jejuni and C. jejuni subsp. doylei; most strains belonged to the latter subspecies. No two strains had identical patterns but within each subspecies two subgroups were identifiable, corresponding to Lior biotypes I and II. Southern blot hybridization analysis with a 16 + 23S rRNA cistron probe from Escherichia coli also showed differences between the various strains, and in a numerical analysis three groupings were formed at 70%S corresponding to C. jejuni subsp. jejuni Lior biotypes I and II, and C. jejuni subsp. doylei. Four of the subspecies doylei strains contained a 3.4-MDa plasmid. These analyses showed that catalase-negative C. jejuni subsp. jejuni were genomically distinguishable from C. jejuni subsp. doylei as were Lior biotypes within subsp. jejuni. Ability to produce catalase is not a feature common to all C. jejuni strains, and our results confirm that some strains of subspecies jejuni may be negative in that character although typical in other respects. DNA pattern heterogeneity was consistent with serological differences between strains.

Molecular subtyping by genome and plasmid analysis ofCampylobacter jejuniserogroups O1 and O2 (Penner) from sporadic and outbreak cases of human diarrhoea

“…Ribopatterns provide a well validated and reproducible means of discriminating between strains in many bacterial species [39], and have proved to be particularly effective in identifying strains of C. jejuni [14,17,[21][22][23][24]. We have shown in previous studies that overall ribopattern similarities broadly reflect the taxonomic affinities of strains within the thermophilic campylobacters.…”

“…The described previously [17,29]. Isolates were biotyped according to the extended scheme of Lior [10].…”

“…Phage typing has been developed but utilized in only a limited number of studies on C. jejuni [13][14][15]. Similarly, DNA (molecular) typing, based on total genomic DNA digest patterns from conventional [14,[16][17][18][19] and pulse field gel electrophoresis [20], ribosomal RNA gene restriction digest patterns [14,17,[21][22][23][24], and plasmid profiling [25], has been applied to a limited extent. Recently, the polymerase chain reaction (PCR) was used to obtain randomly amplified polymorphic DNA (RAPD) profiles.…”

Flagellin gene polymorphism analysis ofCampylobacter jejuniinfecting man and other hosts and comparison with biotyping and somatic antigen serotyping

“…DNA-based typing (genotyping) methods such as restriction endonuclease digest analysis and ribosomal RNA gene [4][5][6][7][8][9][10]. A more simple method of DNA-typing based on arbitrary primer PCR profiling was recently evaluated for C. jejuni and sufficient discrimination was found for epidemiological purposes [10].…”

Revision of species delineation in the genus Ectothiorhodospira.

“…DNA-DNA hybridization was performed following the filter hybridization method of Hernandez et al (1991) with some modifications (Surico et al, 1996). DNA stock solutions were prepared in 0n4 M NaOH, 10 mM EDTA, pH 8, adjusting the concentration to 20 µg ml − ".…”