Continuing Evolution of the Pattern of Quinolone Resistance in Neisseria gonorrhoeae Isolated in Sydney, Australia

Abstract

BACKGROUND AND OBJECTIVES: Multiple phenotypes of quinolone-resistant Neisseria gonorrhoeae isolated in Sydney since 1984 originated in Asia and increased in number and level of resistance in 1995. GOAL: To study the origins, characteristics, and infection pattern of quinolone-resistant Neisseria gonorrhoeae in Sydney from 1995 to 1997 and to compare these results with prior findings. STUDY DESIGN: Quinolone minimal inhibitory concentrations, phenotype, and geographic source of quinolone-resistant Neisseria gonorrhoeae isolated in Sydney from 1995 to 1997 were analyzed. RESULTS: Two hundred nineteen episodes of infection with quinolone-resistant Neisseria gonorrhoeae from 2,236 gonococcal isolates occurred during 1995 through 1997. The rate of isolation of quinolone-resistant Neisseria gonorrhoeae increased significantly at the end of 1996 and was maintained through 1997. The increase resulted from sustained domestic transmission of a limited number of phenotypes in heterosexual patients. CONCLUSION: The pattern of isolation of quinolone-resistant Neisseria gonorrhoeae in Sydney changed from the sporadic isolation of multiple phenotypes of imported quinolone-resistant Neisseria gonorrhoeae to a higher rate of endemic disease caused by a few subtypes. Alterations in antibiotic treatment regimens in the affected patient group were required.