TABLE 1.

MIC of biocides against pre‐ and post‐primed strains of bacteria

Strain	MIC (mg l−1), n = 3
	Hydrogen peroxide	Glutaraldehyde	Benzalkonium chloride	Chlorhexidine
E. coli	32	1024	16	15.6
EcH2O2	64 a	1024	16	15.6
S. aureus	4	512	4	7.8
SaCHG	4	512	4	7.8
P. aeruginosa	32	1024	64	31.3
PaGTA	32	1024	—	31.3
PaBZK	—	—	128 b	—

Note: EcH₂O_2, H₂O₂ primed E. coli; SaCHG, CHG primed S. aureus; PaGTA, GTA primed P. aeruginosa; and PaBZK, BZK primed P. aeruginosa.

^a EcH₂O₂ tolerance to H₂O₂ was unstable.

^b Only in PaBZK was there a stable twofold increase to tolerance BZK.