Effect of penicillin and spectinomycin given for urethritis and cervicitis with Neisseria gonorrhoeae: high prevalence of penicillin-resistant isolates.

Efficacy of single-dose spectinomycin (TRO: 2 g intramuscularly) was compared with that of aqueous procaine penicillin G (APPG:4.8 x 10(6) units) plus 1 g of probenecid for treatment of gonococcal urethritis and cervicitis. Cure rates of the 210 patients who received TRO and 190 patients who received APPG were 97.6% and 91.1%, respectively. MICs of antibiotics were determined using the agar dilution method. Those isolates with MICs of APPG of less than 1.0 microgram/ml had low failure rates (2.9%), while strains with increased resistance to APPG (MICs greater than or equal to 1.0 microgram/ml) had higher failure rates (24%). Treatment failures seen with TRO were not correlated to isolates with the higher MICs. Clinical results suggest TRO could be given for treatment of genital gonorrhoea in Puerto Rico due to the high prevalence of both chromosomally-mediated penicillin-resistant Neisseria gonorrhoeae (20%) and penicillinase-producing Neisseria gonorrhoeae (7.5%) strains and the high rate of failure seen with the use of APPG.