Immunological comparison of constitutive β-lactamases of gram-negative bacteria by neutralization in zymogram gels: Properties of anti-TEM-1 and anti-TEM-2 sera

Abstract

The zymogram technique was applied to a β-lactamase neutralization assay with anti-TEM-1 and anti-TEM-2 sera. Both were shown to contain neutralizing antibodies directed towards various β-lactamases of Gram-negative bacteria. The quantitative neutralization allowed classification into five groups of the 28 β-lactamases used as standards and 61 from clinical isolates. In the first were enzymes such as TEM-1 and TEM-2 including TLE-1, SHV-1, SHV-2, penicillinases of Klebsiella pneumoniae and CTX-1. Partial neutralization distinguished two groups containing the CARB group of enzymes, which are different from PSE-2 and PSE-3, and the MAL penicillinases of Levinea malonatica, which are different from L. amalonatica enzymes. Broad spectrum β-lactamases of K. oxytoca constituted a unique group of partially neutralized enzymes. Among the β-lactamases not neutralized by either serum were the plasmid-mediated OXA-enzymes, various species-specific β-lactamases and cephalosporinases.

The antigenic similarities of the enzymes appeared to correlate with the extent of similarities of their catalytic properties, namely those of penicillinases. Such comparisons between the β-lactamase groups provide an indirect approach to the physiological and structural analysis of established and recently evolved β-lactamases.