Antimicrobial resistance of Neisseria gonorrhoeae in Liberia

The prevalence and molecular characteristics of penicillinase-producing Nei sseria gonorrhoeae (PPNG) and tetracycline-resistant N. gonorrhoeae (TRNG) were determined in 10 clinics in Monrovia, Liberia, to assess the likely ef fectiveness of the current standard treatment with penicillin or tetracycli ne. One hundred gonococcal strains were isolated from 146 urethral swabs an d 261 cervical swabs and screened for susceptibility to ceftriaxone, penici llin, spectinomycin and tetracycline by the disk diffusion method; 83% were resistant to penicillin and 63% to tetracycline. Twenty-one strains from 1 8 men and 3 women with uncomplicated gonorrhoea were subjected to more deta iled characterization. These 21 strains belonged to 5 auxotype/serovar clas ses; 86% were PPNG/TRNG. Three PPNG harboured the 4.4 MDa penicillinase pla smid and 16 the 3.2 MDa plasmid. All TRNG harboured the 25.2 MDa plasmid an d their MICs for tetracycline were >32 mg/L. They gave a PCR product which, according to its restriction pattern, corresponded to the American type te tM gene. By the agar dilution method, all strains exhibited intermediate re sistance to sulphamethoxazole-trimethoprim (19:1) (co-trimoxazole) with MIC s of 8-32 mg/L. Al strains were susceptible to spectinomycin and ciprofloxa cin. The MICs for gentamicin were 4-8 mg/L. The use of effective and afford able antimicrobial chemotherapy with either 500 mg ciprofloxacin or a singl e dose of gentamicin is discussed, with consideration of molecular biologic al, pharmacological and public health aspects.