Table 1

Susceptibilities of high-level cefixime- and ceftriaxone-resistant N. gonorrhoeae strain F89 to various antimicrobials

Class, subclass, and antimicrobialMIC Etesta (S, I, or R)b,cCDS (mm)d
β-Lactams, penicillins
    Penicillin G1 (I)b,c5 (I)
    Ampicillin0.5NDe
    Amdinocillin128ND
    Oxacillin64ND
    Piperacillin0.125ND
    Piperacillin-tazobactam0.016ND
β-Lactams, monobactams, aztreonam64ND
β-Lactams, cephalosporins
    Cefuroxime16 (R)bND
    Cefpodoxime16 (R)b6 (R)
    Ceftazidime16 (R)bND
    Cefotaxime4 (R)b,cND
    Cefixime4 (R)b,cND
    Ceftriaxone2 (1)a (R)b,c3 (R)
    Cefepime16 (R)bND
β-Lactams, carbapenems
    Ertapenem0.016ND
    Meropenem0.016ND
    Imipenem0.5ND
Fluoroquinolones
    Ciprofloxacin>32 (R)b,c4 (R)
    Levofloxacin8ND
    Moxifloxacin4ND
Macrolides
    Azithromycin1 (R)cND
    Erythromycin2ND
Aminoglycosides
    Gentamicin8ND
    Kanamycin16ND
    Tobramycin8ND
Aminocyclitol, spectinomycin16 (S)b,c13 (S)
Tetracyclines, tetracycline2 (R)cND
Glycylcycline, tigecycline0.5ND
Folic acid antagonists, trimethoprim-sulfamethoxazole1ND
Rifamycins, rifampin0.5ND
Chloramphenicol4ND
Nitrofurantoin1ND
Fusidic acid2ND
  • a MICs were determined using the Etest method (AB bioMérieux, Solna, Sweden) according to the instructions from the manufacturer. Agar dilution was additionally performed for ceftriaxone (the result is in parentheses) according to the method described by the Clinical Laboratory and Standards Institute (CLSI) (9). The Etest method is capable of providing half-MIC steps; however, in accordance with the interpretation of the agar dilution method described by the CLSI (9), only whole-MIC steps are given.

  • b Where available, interpretative criteria (S, susceptible; I, intermediate susceptible; R, resistant) from the CLSI (9) were used.

  • c Interpretative criteria (susceptible, intermediate susceptible, resistant) from the European Committee on Antimicrobial Susceptibility Testing (EUCAST; available online at www.eucast.org/Clinical breakpoints [accessed 20 November 2011]) are also reported where available.

  • d The calibrated dichotomous sensitivity (CDS) disc diffusion method (40; http://web.med.unsw.edu.au/cdstest) is used for antimicrobial resistance testing in many countries in the World Health Organization (WHO) Western Pacific Region.

  • e ND, not determined.