Clonality of Campylobacter sputorum bv. paraureolyticus determined by macrorestriction profiling and biotyping, and evidence for long-term persistentinfection in cattle

Eighteen strains of Campylobacter sputorum by. paraureolyticus (isolated ov er a 12-month period from seven dairy cows contained in a single herd) were examined by resistotyping, and macrorestriction profiling using pulsed fie ld gel electrophoresis (PFGE). The resistotypes of these strains were ident ical, although repeat testing indicated resistance to metronidazole was not a reliable trait for typing purposes. Five SmaI-derived genotypes were ide ntified among the 18 strains. In 5 of 7 cows, isolates obtained from the sa me animal, but from different time periods, were genotypically indistinguis hable, indicating persistence of infection. Macrorestriction profiles of 5 strains representing the 5 SmaI genotypes and 8 other strains of C, sputoru m from various sources, were prepared using 4 endonucleases (SmaI, SalI, Ba mHI and KpnI). The only other strain of C. sputorum by. paraureolyticus exa mined (a Canadian isolate from human faeces), was found to have a SmaI macr orestriction profile identical with one of the five clones isolated from th e cattle. Moreover, SalI and BamHI profiles of all by. paraureolyticus stra ins were similar, while digestion with KpnI was not observed. By contrast, the seven strains of C, sputorum by. sputorum yielded various macrorestrict ion profiles with all the enzymes used, and features distinguishing the two biovars studied could be identified. This study indicates that C. sputorum can persist in cattle for at least 12 months and exhibits a clonal populat ion genetic structure.