OxyFile #494

Ozone Inactivation of Streptococcus Faecalis and Staphylococcus 
Aureus in Water as Models of Gram (-) Bacteria

I. Lezcano, R. Pérez-Rey, E. Sánchez, Ch. Baluja, C. Alvarez.

Ozone Research Center, Cuba.

Ozone is a potent germicidal agent.  Inactivation kinetics of 
Pseudomonas aeruginosa and Escherichia coli towards ozone in 
water, as models of Gram (-) bacteria, were studied.  For this 
purpose, water suspensions of 104 - 106 CFU/ml of Pseudomonas 
aeruginosa and Escherichia coli isolated from polluted water and 
Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922, 
were prepared in sterile conditions and treated in a 100 mL bubble 
reactor with ozone, achieving concentrations from 0.3 to 2.61 mg 
of dissolved ozone/L of water, in contact with microorganisms.  
Total inactivation obtained by this procedure varied from 1.04 to 
19.23 minutes depending on the bacterial resistance and the ozone 
concentration applied.  The ATCC strains showed to be more 
sensitive than the environmental isolates; Pseudomonas aeruginosa 
was the most resistant wild strain.  First order inactivation 
kinetics respect to both the concentrations of ozone and 
microorganisms were found, resulting an overall second order 
inactivation kinetics.

Source: 2nd International Symposium on Ozone Applications
        Havana, Cuba - Mach 24-26, 1997.