Identification of C. jejuni subsp. doylei strains by multiplex PCR. A. napAB multiplex PCR. C. jejuni genomic DNAs were amplified with either the nap mpx 1 ("1") or mpx 2 ("2") primer sets; the PCRs were run on a 1% agarose gel. D1: Cjd strain RM2095; D2: Cjd strain 269.97; D3: Cjd strain RM2096; D4: Cjd strain CCUG 18266; J1: Cjj strain NCTC 11168; J2: Cjj strain RM1221. Band sizes in bp are indicated on the left side of the gel. B. Combination speciation and subspeciation PCR. Campylobacter genomic DNAs were amplified with the combined nap mpx 2 and thermophilic lpxA Campylobacter speciation primer sets; PCRs were run on a 2% agarose gel. Cj: Cjj strain NCTC 11168; D1: Cjd strain CCUG 18266; D2: Cjd strain 269.97; Cc: C. coli strain RM2228; Cl: C. lari strain RM2100; Cu: C. upsaliensis strain RM3195; Ch: C. helveticus strain ATCC 51209. Band sizes in bp are indicated on the right side of the gel. Bands resulting from the speciation primer sets are indicated with an asterisk (*).