Table 2. Mean specific activities of β-lactamase (blaA) variants of Y.enterocolitica biotype 1A strains.

blaA variant	No. of strains in which the variant was present(n)	Mean specific activity (μmol/min/mg of protein) of β-lactamase
blaA1	12	0.150 ± 0.02
blaA2	1	0.853
blaA3	16	0.153 ± 0.04
blaA4	4	0.030 ± 0.02
blaA5	1	0.10
blaA6	1	0.20

All values are represented as mean ± standard error of mean (SEM).