Activities of Manogepix and Comparators against 1,435 Recent Fungal Isolates Collected during an International Surveillance Program (2020).

We evaluated the in vitro activity of manogepix and comparator agents against 1,435 contemporary fungal isolates collected worldwide from 73 medical centers in North America, Europe, the Asia-Pacific region, and Latin America during 2020. Of the isolates tested, 74.7% were Candida spp.; 3.7% were non-Candida yeasts, including 27 Cryptococcus neoformans var. grubii (1.9%); 17.1% were Aspergillus spp.; and 4.5% were other molds. All fungal isolates were tested by reference broth microdilution according to CLSI methods. Based on MIC90 values, manogepix (MIC50/MIC90, 0.008/0.06 mg/liter) was 16- to 64-fold more active than anidulafungin, micafungin, and fluconazole against Candida spp. isolates and the most active agent tested. Similarly, manogepix (MIC50/MIC90, 0.5/1 mg/liter) was ≥8-fold more active than anidulafungin, micafungin, and fluconazole against C. neoformans var. grubii. Based on minimum effective concentration for 90% of the isolates tested (MEC90) and MIC90 values, manogepix (MEC90, 0.03 mg/liter) was 16- to 64-fold more potent than itraconazole, posaconazole, and voriconazole (MIC90s, 0.5 to 2 mg/liter) against 246 Aspergillus spp. isolates. Aspergillus fumigatus isolates exhibited a wild-type (WT) phenotype for the mold-active triazoles, including itraconazole (87.0% WT) and voriconazole (96.4% WT). Manogepix was highly active against uncommon species of Candida, non-Candida yeasts, and rare molds, including 11 isolates of Candida auris (MIC50/MIC90, 0.004/0.015 mg/liter) and 12 isolates of Scedosporium spp. (MEC50/MEC90, 0.06/0.12 mg/liter). Additional studies are in progress to evaluate the clinical utility of the manogepix prodrug fosmanogepix in difficult-to-treat resistant fungal infections.

In Vitro Activity of APX001A (Manogepix) and Comparator Agents against 1,706 Fungal Isolates Collected during an International Surveillance Program in 2017.

Current antifungal agents cover a majority of opportunistic fungal pathogens; however, breakthrough invasive fungal infections continue to occur and increasingly involve relatively uncommon yeasts and molds, which often exhibit decreased susceptibility. APX001A (manogepix) is a first-in-class small-molecule inhibitor of the conserved fungal Gwt1 protein. This enzyme is required for acylation of inositol during glycosylphosphatidylinositol anchor biosynthesis. APX001A is active against the major fungal pathogens, i.e., Candida (except Candida krusei), Aspergillus, and hard-to-treat molds, including Fusarium and Scedosporium In this study, we tested APX001A and comparators against 1,706 contemporary clinical fungal isolates collected in 2017 from 68 medical centers in North America (37.3%), Europe (43.4%), the Asia-Pacific region (12.7%), or Latin America (6.6%). Among the isolates tested, 78.5% were Candida spp., 3.9% were non-Candida yeasts, including 30 (1.8%) Cryptococcus neoformans var. grubii isolates, 14.7% were Aspergillus spp., and 2.9% were other molds. All isolates were tested by CLSI reference broth microdilution. APX001A (MIC50, 0.008 µg/ml; MIC90, 0.06 µg/ml) was the most active agent tested against Candida sp. isolates; corresponding anidulafungin, micafungin, and fluconazole MIC90 values were 16- to 64-fold higher. Similarly, APX001A (MIC50, 0.25 µg/ml; MIC90, 0.5 µg/ml) was ≥8-fold more active than anidulafungin, micafungin, and fluconazole against C. neoformans var. grubii Against Aspergillus spp., AXP001A (50% minimal effective concentration [MEC50], 0.015 µg/ml; MEC90, 0.03 µg/ml) was comparable in activity to anidulafungin and micafungin. Aspergillus isolates (>98%) exhibited a wild-type phenotype for the mold-active triazoles (itraconazole, posaconazole, and voriconazole). APX001A was highly active against uncommon species of Candida, non-Candida yeasts, and rare molds, including 11 isolates of Scedosporium spp. (MEC values, 0.015 to 0.06 µg/ml). APX001A demonstrated potent in vitro activity against recent fungal isolates, including echinocandin- and fluconazole-resistant strains. The extended spectrum of APX001A was also notable for its potency against many less common but antifungal-resistant strains. Further studies are in progress to evaluate the clinical utility of the methyl phosphate prodrug, APX001, in difficult-to-treat resistant fungal infections.

Treatment of experimental Pseudomonas corneal ulcers with enoxacin, a quinolone antibiotic.

Enoxacin is a broad-spectrum quinolone-derivative antibiotic. In a rabbit model of keratitis caused by a Pseudomonas species, enoxacin (3 mg/mL) was as effective as gentamicin sulfate (3 mg/mL) and enoxacin (10 mg/mL) in reducing viable bacterial counts in corneas after 24 hours of hourly therapy with eye drops. Bacterial counts were reduced by about 5000-fold by enoxacin treatment when compared with placebo-treated controls. Penetration studies of topical enoxacin (3 mg/mL) showed that concentrations in cornea and aqueous humor reached levels above reported minimal inhibitory concentrations when an epithelial defect was present. Further investigation of enoxacin for treatment of ocular disease is warranted.

In vitro activity of CI-934, a quinolone carboxylic acid active against gram-positive and -negative bacteria.

CI-934 is a totally synthetic difluorinated quinolinecarboxylic acid with an ethyl-amino-methyl pyrrolidine side chain, which has broad-spectrum antibacterial activity, including particular potency directed against streptococci and staphylococci. The CI-934 MIC (micrograms per milliliter) for 90% of the strains tested was 0.4 (range, 0.2 to 0.8) for a group of streptococci (pneumococci, viridans streptococci, Streptococcus faecalis, and Lancefield groups A, B, and C), 0.2 (0.05 to 0.2) for staphylococci (including methicillin-resistant Staphylococcus aureus), 0.025 (less than or equal to 0.003 to 0.025) for Haemophilus influenzae and Neisseria gonorrhoeae, 1.6 (0.1 to 25) for Enterobacteriaceae, 25 (3.1 to 25) for Pseudomonas aeruginosa, and 1.6 (0.05 to 3.1) for non-Bacteroides anaerobe species. CI-934 was equally active in vitro against multi-drug-resistant and -sensitive isolates, and cross-resistance was not apparent. Potency increased with alkalinity and was somewhat lower in urine. CI-934 was bactericidal. Inhibitory activity was generally unaffected by anaerobiosis, light, changes in inoculum size or cation concentration, or addition of human serum or sodium cholate.

Enoxacin: in-vitro and animal evaluation as a parenteral and oral agent against hospital bacterial isolates.

Enoxacin was evaluated in in-vitro tests and in studies of effectiveness and blood concentrations in the mouse. Enoxacin was active against both susceptible and multiresistant hospital isolates of Enterobacteriaceae, Pseudomonas aeruginosa, Haemophilus influenzae, Neisseria gonorrhoeae and staphylococci. Less susceptible were streptococci and anaerobes. Of nine quinolones tested, only norfloxacin was equivalent in vitro. The MBCs of enoxacin were one- to twofold greater than the MICs, and enoxacin was rapidly bactericidal. No single-step resistant mutants could be detected at 10 mg/l against large inocula and six to 11 steps were required for selection of resistant clones. In systemic mouse infections, enoxacin was effective in a single oral or subcutaneous dose against one strain each of Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Providencia rettgeri and Ps. aeruginosa, and two Staphylococcus aureus strains. Single oral and subcutaneous enoxacin doses (50 mg/kg) gave peak mouse blood levels of 4.9 and 9.5 mg/l and an elimination half-life of 1.8 h.