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Efficacy of peroxygen compounds against glutaraldehyde-resistant mycobacteria
1Minntech Corporation, Minneapolis, MN 55447, USA.
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.
Insights
A new germicide combining hydrogen peroxide and peracetic acid effectively kills glutaraldehyde-resistant mycobacteria, addressing a critical gap in high-level disinfection. This synergistic mixture offers superior disinfection for semicritical devices compared to individual agents.
Area of Science:
- Microbiology
- Infectious Disease Prevention
- Sterilization and Disinfection
Background:
- Semicritical medical devices require high-level disinfection to prevent patient cross-infection.
- Mycobacteria resistant to glutaraldehyde pose a challenge for current disinfection protocols.
- The efficacy of alternative disinfectants against resistant strains needs thorough evaluation.
Purpose of the Study:
- To assess the efficacy of hydrogen peroxide, peracetic acid, and a combined germicide (Cidex PA) against glutaraldehyde-resistant and nonresistant mycobacteria.
- To determine if a synergistic effect exists between hydrogen peroxide and peracetic acid for mycobacterial disinfection.
Main Methods:
- Bacterial suspensions of resistant and control mycobacteria were exposed to test chemicals.
- Exposure times varied, followed by neutralization and enumeration of surviving microorganisms.
- Efficacy was measured by log reduction in bacterial counts.
Main Results:
- Individual hydrogen peroxide (10%) and acidified hydrogen peroxide (6%) showed limited activity against resistant strains.
- Peracetic acid (0.07%) demonstrated low to moderate activity against resistant mycobacteria.
- Cidex PA (0.07% peracetic acid, 1% hydrogen peroxide) achieved a 6-log reduction in 10 minutes against all strains, indicating high efficacy.
Conclusions:
- A synergistic mixture of hydrogen peroxide and peracetic acid (Cidex PA) is highly effective against both glutaraldehyde-resistant and nonresistant mycobacteria.
- The combined formulation offers superior antimycobacterial activity compared to individual peroxygen compounds.
- This finding supports the use of synergistic peroxygen mixtures for high-level disinfection of semicritical devices.