The ACT gene encodes a plasmid-borne AmpC β-lactamase that confers resistance to broad-spectrum cephalosporins. In clinical Klebsiella pneumoniae isolates ACT-1 is inducible by cephalosporins, and when combined with porin loss it can drive high-level carbapenem/cephalosporin resistance. Including ACT in the panel flags AmpC-mediated resistance that may otherwise be missed (Philippon et al. 2002, Reisbig & Hanson 2002).
Philippon, A., Arlet, G., & Jacoby, G. A. (2002). Plasmid-determined AmpC-type beta-lactamases. Antimicrobial agents and chemotherapy, 46(1), 1–11. https://doi.org/10.1128/AAC.46.1.1-11.2002
Reisbig, M. D., & Hanson, N. D. (2002). The ACT-1 plasmid-encoded AmpC beta-lactamase is inducible: detection in a complex beta-lactamase background. The Journal of antimicrobial chemotherapy, 49(3), 557–560. https://doi.org/10.1093/jac/49.3.557
