Common β-lactamase genes, examples of pathogenic hosts and the antibiotics that they hydrolyse³⁹ (compiled with the aid of the Comprehensive Antibiotic Resistance Database; CARD; https://card.mcmaster.ca)⁴⁰.

β-Lactamase class	Examples of β-lactamase genes	Host pathogens	Substrates	Ref.
Class A	IMI	Enterobacter cloacae	Imipenem	41
	CTX-M	Escherichia coli, K. pneumoniae	Cephalosporins (cefotaxime [CTX] activity greatest)	42
		Salmonella enterica, P. mirabilis
	KPC	K. pneumoniae, A. baumannii	Carbapenems, cephalosporins	43–45
		P. aeruginosa, S. enterica
	SME	Serratia marcescens	Carbapenems	46
	BlaZ	S. aureus	Penicillin, cephalosporin, carbapenem	47
	SHV	K. pneumonia	Penicillins, cephalosporins, carbapenem	48
		E. coli
Class B (metallo-)	IMP	Enteric Gram negative bacteria	Carbapenem, cephalosporins	49
		Pseudomonas spp., Acinetobacter spp.
	VIM	P. aeruginosa	Penicillins, cephalosporins, carbapenem	49, 50
	NDM-1	E. coli, K. pneumoniae, E. cloacae	Carbapenems, cephalosporins, aztreonam, penicillins	51
		Proteus spp., Citrobacter freundii
Class C	AmpC	Enterobacteriaceae	Cephalosporins, penicillin	52
Class D	OXA	Enterobacter spp., Serratia spp., C. freundii, Aeromonas spp., Proteus spp., Providencia spp., Morganella morganii (ESCAPPMs)	Penicillins, cephalosporins, carbapenems	53