Table 4.
Substitutions in amino acids in the N-terminal hypervariable region of the spaA gene and number of C-terminal tandem repeats in 165 E. rhusiopathiae field isolates and serotype reference strains compared with the corresponding sequence of E. rhusiopathiae Fujisawa strainc
| E. rhusiophatiae strain or group (no. of isolates) | Substitutions in N-terminal nucleotides (amino acid position)a,b | No. of C-terminal tandem repeats | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Nucleotide (aa 55) | Nucleotide (aa 70) | Nucleotide (aa 101) | Nucleotide (aa 178) | Nucleotide (aa 195) | Nucleotide (aa 203) | Nucleotide (aa 257) | Nucleotide (aa 303) | |||
| Fujisawa serotype 1a | GTA (Val) | AAA (Lys) | AAC (Asn) | GGT (Gly) | GAT (Asp) | ATT (Ile) | CTT Leu | GGG (Gly) | 9 | |
| Field isolates (No.) | Group I (87) | ATA (Ile) | AAT (Asn) | GAT (Asp) | AAT (Asn) | ATT (Ile) | GAG (Gln) | 8-11, 13 | ||
| Group II (36) | AGC (Ser) | ATT (Ile) | 7-10 | |||||||
| Group III (37) | ATT (Ile) | 8, 9 | ||||||||
| Group IV (1) | ATT (Ile) | GAG (Gln) | 8 | |||||||
| Group V (4) | ATG (Met) | ATT (Ile) | 9 | |||||||
| Serotype reference strains | Serotype 1a (Koganei) 5, 15 | ATA (Ile) | AAT (Asn) | GAT (Asp) | AAT (Asn) | ATT (Ile) | GAG (Gln) | 9 | ||
| Serotype 8, 17 | AGC (Ser) | ATT (Ile) | 9 | |||||||
| Serotype 1b, 9, 12, 16, N | ATT (Ile) | 8, 9 | ||||||||
| Serotype 2 | ATA (Ile) | AAT (Asn) | ATT (Ile) | 9 | ||||||
aAsp aspartic acid; Asn asparagine; Gln glutamine; Ile isoleucine; Leu leucine; Lys lysine; Met methionine; Val valine.
bUnderlined character, nucleotide different from those at the same position; empty fields indicate absence of amino acid substitutions compared with the Fujisawa strain.
cNucleotide sequences of spaA genes of Fujisawa strain and of E. rhusiopathiae serotype reference strains were obtained from GenBank (AB259652, strain Fujisawa, serotype 1a; AB024082, Koganei, serotype 1a; AB259653, 442/1E1, serotype 1b; AB259654, ATCC19414T, serotype 2; AB259655, Pècs 67, serotype 5; AB259656, Goda, serotype 8; AB290347, Kaparek, serotype 9; AB259657, Pècs 9, serotype 12; AB259658, Pècs 3597, serotype 15; AB259659, Tanzania, serotype 16; AB259660, 545, serotype 17; AB259661, MEW22, serotype N) and translated into amino acid sequences using RidomSeqSphere. Reference strains for other serotypes were not included as they chiefly harbor spaB genes (serotypes 4, 6, 11, 19, and 21) or a spaC gene (serotype 18), respectively [15].