Amplified fragment length polymorphism, serotyping, and quinolone resistance of Campylobacter jejuni and Campylobacter coli strains from chicken-related samples and humans in Taiwan.

The high-resolution genotyping method of amplified fragment length polymorphism (AFLP) analysis was used to study the genetic relationships between Campylobacter jejuni isolates from chicken-related samples (n = 32) and humans (n = 27) as well as between Campylobacter coli isolates from chicken-related samples (n = 27) and humans (n = 5). These isolates were collected between 1994 and 2003 in Taiwan. All C. jejuni and C. coli isolates showed highly heterogeneous fingerprints. C. jejuni isolates were separated in two distinct genetic clusters (A and B) at 40% genetic similarity and 42 different AFLP types at 90% similarity. However, three clusters at 40% genetic similarity and 33 different AFLP types at 90% similarity were observed in C. coli isolates. These results showed that AFLP analysis could be used to identify individual isolates of two Campylobacter species. Among C. jejuni isolates, the predominant AFLP type 1 was observed in five (7.9%) isolates, and types 5 and 12 in four (6.3%) isolates each. Cluster B consisted of 10 isolates, while the majority of isolates (n = 53) belonged to cluster A. In some AFLP types (1, 5, 12, 14 and 31), AFLP fingerprints of chicken-related isolates were closely related genetically to those of isolates from humans with gastroenteritis. The predominant serotypes in C. jejuni isolates were B:2 and Y:37. All isolates belonging to serotype O:19 grouped into one single AFLP type. Some chicken samples yielded multiple isolates of Campylobacter harboring simultaneously quinolone-resistant and quinolone-sensitive isolates attributed to the same species, or harboring C. jejuni and C. coli that have the characteristics of quinolone resistance.