VARIATION IN HYDROGEN-PEROXIDE SENSITIVITY BETWEEN DIFFERENT STRAINS OF NEISSERIA-GONORRHOEAE IS DEPENDENT ON FACTORS IN ADDITION TO CATALASE ACTIVITY

Catalase, which catalyzes the reduction of hydrogen peroxide to oxygen and water, is considered the primary defense of Neisseria gonorrhoeae against exogenous hydrogen peroxide. Recent reports have demonstrated drastically different sensitivities of the organism to hydrogen perox ide ranging from greater than 80% survival after challenge with 30 mM hydrogen peroxide to less than 0.001% survival after challenge with 10 mM hydrogen peroxide. In this study we have examined the hydrogen per oxide sensitivities of six clinical gonococcal isolates. The study dem onstrates that the variations in gonococcal hydrogen peroxide sensitiv ities previously reported can be attributed to (i) differences in expe rimental methods employed or (ii) variation among different gonococcal strains. All of the gonococcal isolates examined generated similar co ncentrations of catalase, implying that the differences in the H2O2 se nsitivity observed may depend on factors in addition to catalase.