Multilocus sequence typing reveals genetic diversity of foodborne Arcobacter butzleri isolates in the North of Spain

•We analyzed forty-five foodborne Arcobacter butzleri isolates by MLST.•We observed great genetic diversity among A. butzleri isolates.•Seventy-four new alleles and 33 new STs were identified.•For the first time, gene transfer from A. skirrowii to A. butzleri was observed.

The emerging pathogen Arcobacter butzleri is being increasingly isolated from different animal food products but the routes of its transmission to human are not well established yet. Typing methods would be useful in gaining such knowledge. Here we report the great genetic diversity observed among A. butzleri isolates from different food products. Forty-five isolates were analyzed by Multilocus Sequence Typing (MLST). A total of 157 alleles were identified across all seven loci, ranging from 16 alleles at glnA to 31 at glyA. MLST differentiated the isolates into 34 sequence types (STs), with the majority of isolates containing a unique sequence type. Seventy-four new alleles were identified, which resulted in the assignment of 33 new STs. No association of alleles or STs with food source was observed. For the first time, lateral gene transfer from Arcobacter skirrowii to A. butzleri at the glyA locus is also reported.