Efficacy of peroxygen compounds against glutaraldehyde-resistant mycobacteria.
BACKGROUND
To prevent cross-infection of patients, semicritical devices must be high-level disinfected by a product capable of destroying mycobacteria. Glutaraldehyde is commonly used; however, recent studies showed that glutaraldehyde-resistant mycobacteria could survive treatment with this chemical for extended exposure times. Our study tested hydrogen peroxide, peracetic acid, and a germicide (Cidex PA, Advanced Sterilization Products, Irvine, Calif) containing a mixture of the 2 peroxygen compounds for their ability to kill both glutaraldehyde-resistant and nonresistant (control) mycobacteria.


METHODS
Bacterial suspensions were exposed to the test chemicals for various periods followed by neutralization and enumeration of survivors.


RESULTS
Hydrogen peroxide at 10% and acidified hydrogen peroxide at 6% had low activity (<4 log reduction in 60 minutes exposure) against glutaraldehyde-resistant strains and slightly higher activity (4 log to 6 log reduction in 60 minutes) against the control strains. Peracetic acid at 0.07% had low to moderate activity (0.6 log to 6 log reduction in 60 minutes) against the resistant organisms and moderate to high activity (4 log to 6 log reduction in 10 minutes) against the control strains. Cidex PA, which contains a mixture of 0.07% peracetic acid and 1% hydrogen peroxide, had high activity (6 log reduction in 10 minutes) against all organisms. Efficacy of 0.8% phenol, a standard reference solution, did not correlate with efficacy of the peroxygen compounds.


CONCLUSIONS
Hydrogen peroxide and peracetic acid had much higher activity toward mycobacteria when combined as a synergistic mixture than when evaluated individually.
Stanley
P M
PM
Minntech Corporation, Minneapolis, MN 55447, USA.
D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D005976:Glutaral / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D016015:Logistic Models; D008826:Microbial Sensitivity Tests; D009161:Mycobacterium / Q000187:drug effects*; D009163:Mycobacterium bovis / Q000187:drug effects; D016877:Oxidants / Q000494:pharmacology*; D010463:Peracetic Acid / Q000494:pharmacology; D010545:Peroxides / Q000494:pharmacology*; D010756:Phosphoric Acids / Q000494:pharmacology
D004202:Disinfectants; D016877:Oxidants; D010545:Peroxides; D010756:Phosphoric Acids; D006861:Hydrogen Peroxide; D010463:Peracetic Acid; D005976:Glutaral