Epidemiologic aspects of control of penicillinase-producing Neisseria gonorrhoeae.

Although first identified in 1976, penicillinase-producing Neisseria gonorrhoeae (PPNG) began to have significant epidemiologic impact in the United States only after 1980. The epidemic curve has been marked by a series of successive sigmoidal increases, the result of staggered epidemic activity in Los Angeles, California, New York, New York, and Miami. The most recent increase and current plateau has led to a provisional total of 16,608 cases for 1986, with the proportion of PPNG isolates as high as 30% in some communities. The intensity of PPNG transmission appears to parallel that of gonorrhea in general, with high attack rates in central city areas (i.e., among core groups) and with a dimmishing gradient outward from the center. The endemicity of PPNG is related in a general way to the size of the inoculum. A county experiencing seven cases in a month at the time of introduction, for example, has less than a 50% probability of reverting to zero cases during the next 12 months. It would appear that the inoculation of PPNG organisms into a community leads to a "take" when high-level transmitters of gonorrhea are affected. Though current projections suggest as many as 35,000-40,000 cases of PPNG infections by 1991, control programs that focus resources on core-group transmitters of gonorrhea may alter that course.