The
antibiotic susceptibilities of Neisseria gonorrhoeae isolates obtained from patients attending
sexually transmitted disease clinics in Cholburi and Bangkok, Thailand, were determined by
agar dilution. Some 28.2% of isolates produced
beta-lactamase. A total of 97.9% of
beta-lactamase-positive and 51% of
beta-lactamase-negative isolates tested were resistant to
penicillin (MICs, greater than or equal to 2 micrograms/ml), 70% of isolates tested were resistant to
tetracycline (MICs, greater than or equal to 2 micrograms/ml), and 91% of isolates tested were susceptible to
spectinomycin (MICs, less than or equal to 64 micrograms/ml). The MICs for 90% of isolates for the other drugs tested were 2 micrograms/ml for
erythromycin, 2 micrograms/ml for
cefoxitin, 1 micrograms/ml for
cefuroxime, 0.125 micrograms/ml for
cefpodoxime, 0.06 micrograms/ml for
cefotaxime, 0.25 micrograms/ml for
ceftazidime, 0.03 micrograms/ml for
ceftizoxime, 0.03 micrograms/ml for
ceftriaxone, 0.03 micrograms/ml for
cefixime, 0.06 micrograms/ml for
aztreonam, 0.008 micrograms/ml for
ciprofloxacin, 0.125 micrograms/ml for
norfloxacin, and 0.075 micrograms/ml for
ofloxacin. Fewer than 1.5% of isolates were resistant to the extended-spectrum
cephalosporins tested. Some 0.3% or fewer isolates were resistant to broad-spectrum
cephalosporins,
fluoroquinolones, or the
monobactam aztreonam. Antibiotic resistance among N. gonorrhoeae isolates from Cholburi and Bangkok in May 1990 appeared to be primarily limited to
penicillin and
tetracycline, which are no longer used to control
gonorrhea.
Spectinomycin, which has been in general use against
gonorrhea in Thailand since 1983, has dwindling utility, with resistance at a level of 8.9%.