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Antibiotic Susceptibility Patterns and Plasmid Profiles of Penicillinase-Producing Neisseria gonorrhoeae Strains in Durban, South Africa, 1990–1993

1997; Lippincott Williams & Wilkins; Volume: 24; Issue: 1 Linguagem: Inglês

10.1097/00007435-199701000-00005

1537-4521

Hafizah Y. Chenia, Balakrishna Pillay, A A Hoosen, Deenan Pillay,

Pneumonia and Respiratory Infections

The appearance of strains of Neisseria gonorrhoeae resistant, both chromosomally and plasmid-mediated, to penicillin and other antibiotics makes this versatile pathogen difficult to treat. There is, therefore, a need for surveillance of N. gonorrhoeae strains to determine the efficacy of current therapeutic measures.To survey the antibiotic susceptibilities and plasmid profiles of penicillinase-producing N. gonorrhoeae strains isolated over a 4-year period.Penicillinase-producing N. gonorrhoeae strains were detected by the chromogenic cephalosporin test. Minimum inhibitory concentrations to penicillin G, tetracycline, ceftriaxone, and ciprofloxacin were determined using the E-test. Plasmid DNA was obtained by the alkaline lysis method and profiles generated.Penicillinase-producing N. gonorrhoeae strains increased from 16.4% to 19.0% in the period from 1990 through 1993. Although all strains were resistant to penicillin, strains were susceptible to varying levels of ciprofloxacin, ceftriaxone, and even tetracycline. All penicillinase-producing N. gonorrhoeae strains possessed the 2.6-megadalton cryptic plasmid, and in addition 87.7% contained the 24.5-megadalton conjugative plasmid. Of the six known gonococcal beta-lactamase plasmids, the 4.4-megadalton Asian and 3.2-megadalton African plasmids were predominant. The most prevalent plasmid profile contained the 2.6-megadalton cryptic, 24.5-megadalton conjugative, and 4.4-megadalton Asian plasmids.To ensure effective treatment of gonorrhea, continued surveillance of the antimicrobial susceptibilities and plasmid profiles of penicillinase-producing N. gonorrhoeae strains is necessary.In South Africa, 321 gonococcal strains were isolated from urethral exudates of adult men presenting with acute urethritis at the Sexually Transmitted Diseases Clinic at King Edward VIII Hospital in Durban during 1990-1993. The purpose was to examine the in vitro susceptibility patterns and plasmid profiles of penicillinase-producing Neisseria gonorrhoeae (PPNG) strains. 17.8% of the strains were PPNG strains. During 1990-1993, the PPNG prevalence increased from 16.4% to 19%. 96.5% of the PPNG strains were sensitive to ceftriaxone with minimum inhibitory concentrations (MICs) of no more than 0.25 g/ml. 94.7% were sensitive to ciprofloxacin with MICs of no more than 0.06 g/ml. 82.5% were sensitive to tetracycline with MICs of no more than 0.25 g/ml. The fact that all PPNG strains had the 2.6 megadalton (MDa) cryptic plasmid suggests that this plasmid confers a selective advantage to the gonococcus. 87.7% also had the 24.5 MDa conjugative plasmid. High prevalence of this plasmid in the PPNG strains may account for the increased prevalence of these strains. The predominant beta-lactamase plasmid type was the 4.4 MDa Asian plasmid (77.2%), not the 3.2 MDa African plasmid. The high prevalence of the Asian plasmid may be because Durban is an important port city and tourist destination for people from Asia. The most common plasmid profile of the PPNG strains contained the 2.6 MDa cryptic, 24.5 MDa conjugative, and 4.4 MDa Asian plasmids (68.4%). Since N gonorrhoeae has several antibiotic resistance mechanisms, epidemiologists should monitor the effectiveness of single-dose treatment and conduct surveillance of trends in resistance in order to achieve effective control of gonorrhea.