Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/29/2016
Publication Date: N/A
Technical Abstract: Bordetella bronchiseptica is a widespread bacterial pathogen that infects a variety of domesticated and wild animals. Multilocus sequence typing (MLST) and PvuII ribotyping have proven useful to distinguish among strains of B. bronchiseptica. Both are highly discriminatory and have been used to infer relationships among isolates and identify likely sources of exposure. It is unclear which of these methods is most discriminatory since they have not been directly compared using a single set of isolates and relatively few isolates have been typed by both methods. The purpose of this study was to compare the discriminatory power of these methods using a single set of geographically and genetically diverse strains. A total of 122 isolates were analyzed, including representatives of the 22 PvuII ribotypes so far recognized and 25 of the 61 MLST sequence types currently associated with B. bronchiseptica isolates in the Bordetella PubMLST database. Isolates were sourced from the United States, Europe, Israel and Australia and include 24 from humans, 20 from seals, 17 from pigs, 13 from turkeys, 12 from rabbits, 10 from dogs, 8 from guinea pigs, 7 from horses, 6 from cats, 3 from koalas, 1 from a leopard and 1 of unknown origin. A total of 32 ribotype patterns were identified based on various combinations of 35 restriction fragments ranging in size from ~1.8 Kb to 5.9 Kb. DNA from one isolate could not be digested completely with PvuII such that a ribotype could not be assigned. In comparison, all isolates were typeable by MLST and a total of 30 sequence types were identified. The discrimination indices for ribotyping and MLST are nearly identical, 0.920 and 0.919, respectively. Nonetheless, for 10 ribotypes and 10 MLST sequence types, the alternative method discriminates among isolates that otherwise type identically. These data indicate PvuII ribotyping and MLST are complementary but equally discriminatory methods. Because MLST offers practical advantages over ribotyping, including ease of standardization, scalability, portability and the ability to type all isolates, it is the preferred primary typing tool for B. bronchiseptica. PvuII ribotyping provides a secondary method that may be applied to further discriminate isolates not distinguishable by MLST.