Inactivation of Chlamydia trachomatis and Chlamydia (Chlamydophila) pneumoniae by ozone

Aims: To clarify the inhibitory effects of ozone on Chlamydia trachomatis and C. pneumoniae. Methods and Results: Cell culture was performed using HeLa229 cells for C. trachomatis, and Human Line cells for C. pneumoniae. C. trachomatis strain D/UW-3/Cx and C. pneumoniae strain AR-39 were used. Ozone water was generated by an ozone water dispenser and diluted to desired concentration just before each experiment. Preinoculation minimum cidal concentration (MCC) and postinoculation MCC methods were employed. In preinoculation MCC, chlamydial strains were treated with serially diluted ozone water followed by inoculation to cells. In postinoculation method, chlamydial strains were inoculated to cells and incubated for 24 h. Then infected cells were treated with ozone water, followed by additional incubation for 48 It. Complete inactivation was obtained in preinoculation MCC method at 0.5 ppm of ozone water for 30 s, or 4 ppm for 5 s. Conclusion: Ozone at a concentration of 4 ppm was enough for immediate inactivation of both C. trachomatis and C. pneumoniae. Significance and Impact of the Study: Ozone water at 4 ppm should be applicable for prevention of C trachomatis urogenital infections.