Nourseothricin as a novel therapeutic agent against : and evaluations using -a pilot study.

has developed resistance to multiple antibiotics, making the search for novel antimicrobial agents essential. This pilot study evaluates the and efficacy of nourseothricin, a streptothricin family antibiotic mixture primarily composed of streptothricin F, against , a previously unexplored therapeutic option. The minimum inhibitory concentrations (MICs) of nourseothricin were determined using the agar dilution method on a panel of strains, including multidrug-resistant isolates. The efficacy was assessed using the infection model, where larvae were infected with and treated with varying concentrations of nourseothricin. Survival rates were compared to those of ceftriaxone-treated and untreated control groups. Nourseothricin inhibited the growth of all tested strains, with MIC values ranging from 16 to 32 µg/mL, independent of resistance to ceftriaxone, ciprofloxacin, or azithromycin. , treatment with nourseothricin significantly improved larval survival compared to the untreated control group ( < 0.01). The highest survival rate was observed with a 32 µg/mL dose, comparable to that of ceftriaxone-treated groups. Nourseothricin exhibited activity against , including multidrug-resistant strains. The results, obtained in a larval model, suggest that nourseothricin may warrant further investigation as a candidate compound for the treatment of gonorrhea, although its clinical potential remains to be evaluated in mammalian systems.IMPORTANCEThe emergence of multidrug-resistant has made the development of new treatments a critical priority. This study is the first to evaluate the efficacy of nourseothricin against , demonstrating its activity even against resistant strains. In addition to its efficacy, treatment with nourseothricin improved survival in an infection model, suggesting its potential as a therapeutic option. Given the increasing limitations of existing antibiotics, these findings support further investigation into nourseothricin as a candidate for future gonorrhea treatment.