Quinolone-resistant Neisseria gonorrhoeae isolated in Sydney, Australia, 1991 to 1995

Background and Objectives: Quinolone antibiotics are used widely for the treatment of gonorrhea, but resistant strains appeared in Sydney in 1984, treatment failure with high-dose regimens in 1991, and isolates with very high minimal inhibitory concentrations (MICs) (16 mg/l) in 1994. Goals: To examine the frequency, source, and characteristics of Quinolone-resistant Neisseria gonorrhoeae (QRNG) in Sydney from 1991 to 1995 and to compare these data with those obtained from 1984 to 1990. Study Design: The antibiotic sensitivity, auxotype-serovar class, and geographic source of QRNG isolated in Sydney from January 1, 1991 to June 30, 1995 were analyzed. Results: One hundred seven QRNG were isolated from 97 patients from 1991 to 1995. The number, proportion, and MICs of QRNG increased slowly in the first 4 years of the study and rapidly in the last 6 months. Most QRNG were isolated from travelers entering Sydney from Asia. Twenty-seven different auxotype-serovar classes were detected including 6 auxotype-serovar classes in 14 isolates with high-level quinolone resistance (MIC, 16 mg/l). Conclusions: QRNG isolated in Sydney during the past decade originated in Asia as multiple gonococcal subtypes and increased substantially in numbers and levels of resistance in 1995.