RX-04C

Pyrrolocytosines RX-04A to -D are designed to bind to the bacterial 50S ribosomal subunit differently from currently used antibiotics. The four analogs had broad anti-Gram-negative activity: RX-04A—the most active analog—inhibited 94.7% of clinical Enterobacteriaceae , Acinetobacter baumannii , and Pseudomonas aeruginosa at 0.5 to 4 μg/ml, with no MICs of >8 μg/ml.