Combination therapy for gonorrhoea: in vitro synergy testing

Area of Science:

• Microbiology
• Infectious Diseases
• Pharmacology

Background:

• Antimicrobial resistance in Neisseria gonorrhoeae is a growing global health concern.
• Combination antimicrobial therapy is recommended to mitigate treatment failures.
• This study evaluates current and alternative treatment regimens against Neisseria gonorrhoeae.

Purpose of the Study:

• To assess the in vitro activity of ceftriaxone or cefixime plus azithromycin.
• To evaluate the in vitro activity of gentamicin plus azithromycin.
• To determine potential future treatment options for gonorrhea.

Main Methods:

• Utilized agar dilution method to test 64 Neisseria gonorrhoeae isolates.
• Determined antimicrobial activity using fractional inhibitory concentration index (FICI).
• Evaluated combinations including ceftriaxone, cefixime, gentamicin, and azithromycin.

Main Results:

• No antagonistic interactions were observed for any tested antimicrobial combinations.
• Ceftriaxone/cefixime plus azithromycin showed additivity/indifference (mean FICI 2.0).
• Gentamicin plus azithromycin demonstrated additivity/indifference (mean FICI 1.7) against all isolates.

Conclusions:

• Current UK national guidelines for gonorrhea treatment are supported by these findings.
• Gentamicin plus azithromycin presents a viable future treatment option.
• Further in vivo and clinical studies are necessary to confirm efficacy.