Antimicrobial susceptibility patterns of gonococcal isolates in Pretoria, South Africa, over a 20-year period (1984-2004)

Abstract

This paper reviews the susceptibility profiles of Neisseria gonorrhoeae over a 20-year period in the Pretoria region. Endourethral specimens were collected from adult men with symptoms of urethritis attending primary health care clinics and private medical practitioners. These swabs were plated on enriched media for isolation of N. gonorrhoeae. Antimicrobial susceptibility of the organisms was performed using the disc diffusion and agar dilution methods. Plasmid analyses were performed on beta-lactamase-producing isolates. Penicillase-producing N. gonorrhoeae strains increased from 4% to 16%, whilst chromosomally mediated penicillin-resistant strains increased dramatically from 0% to 16% from 1984 to 2004. There was an equal distribution of the 3.2 MDa African and 4.4 MDa Asian plasmids. High-level tetracycline-resistant strains (36%) were detected for the first time in 2004. Ciprofloxacin resistance emerged at 7% in the same year. Gonococcal isolates remained susceptible to cefoxitin, ceftriaxone, cefpodoxime, and spectinomycin. However, the minimum inhibitory concentration values for spectinomycin were very close to the breakpoint. We have shown a continuing increase in resistance to penicillin (plasmid and chromosomal), the emergence of high-level tetracycline resistance and an emergence of resistance to ciprofloxacin. Susceptibility testing is essential for successful therapeutic outcomes and needs to be performed in an ongoing basis.