Antimicrobial activity of enacyloxin IIa and gladiolin against the urogenital pathogens Neisseria gonorrhoeae and Ureaplasma spp.

AIMS To determine the antimicrobial activity of enacyloxin IIa and gladiolin against N. gonorrhoeae and Ureaplasma spp. METHODS AND RESULTS The Burkholderia polyketide antibiotics enacyloxin IIa and gladiolin were tested against 14 N. gonorrhoeae and 10 Ureaplasma spp. isolates including multi-drug resistant N. gonorrhoeae isolates WHO V, WHO X and WHO Z as well as macrolide, tetracycline and ciprofloxacin resistant ureaplasmas. Susceptibility testing of N. gonorrhoeae were carried out by agar dilution, whereas broth micro-dilution and growth kinetic assays was used for Ureaplasma spp. The MIC range for enacyloxin IIa and gladiolin against N. gonorrhoeae was 0.015 - 0.06 mg/L and 1 - 2 mg/L, respectively. The presence of resistance to front line antibiotics had no effect on MIC values. The MIC range for enacyloxin IIa against Ureaplasma spp. was 4 - 32 mg/L with a clear dose-dependent effect when observed using a growth kinetic assay. Gladiolin had no antimicrobial activity on Ureaplasma spp. at 32 mg/L and limited impact on growth kinetics. CONCLUSIONS Enacyloxin IIa and gladiolin antibiotics have antimicrobial activity against a range of antibiotic susceptible and resistant N. gonorrhoeae and Ureaplasma isolates. SIGNIFICANCE AND IMPACT OF STUDY This study highlights the potential for a new class of antimicrobial against pathogens in which limited antibiotics are available. Development of these compounds warrants further investigation in the face of emerging extensively-drug resistant strains.