Biochemical, immunological and physicochemical comparisons between OHIO-1 and four SHV-type β-lactamases

The biochemical, immunological and physicochemical properties of the beta-lactamase OHIO-1 were compared to those of four beta-lactamases commonly found in Klebsiella pneumoniae: SHV-1, SHV-3 and the beta-lactamases of strains GN 11-03 and GN 422. The substrate profile of SHV-1, OHIO-1 and of the beta-lactamases GN 11-03 and GN 422 were similar, while that of SHV-3 appeared comparable to that of the extended spectrum SHV-2. Moreover, anti-TEM-1 serum inactivated OHIO-1 as well as SHV-1 and the beta-lactamases of strains GN 11-03 and GN 422. Analysis of the electrophoretic mobilities, isoelectric points and titration curves demonstrated that OHIO-1 and the 4 other beta-lactamases examined were closely related variants. From these findings it appears that OHIO-1 could be classified among the SHV-type beta-lactamases.