Anti-bacterial activity of synthetic N-heterocyclic oxidizing compounds

Synthetic chlorochromate derivatives of pyridine and quinoline were active in vitro against type cultures of Escherichia coli (ATCC 128), Staphylococcus aureus (ATCC 14775), Pseudomonas aeruginosa (ATCC 10145) and Bacillus subtilis (NCTC 8236). The minimum inhibitory concentrations (MIC) were 125-250 micrograms ml-1 and 250-500 micrograms ml-1 for pyridinium chlorochromate and quinolinium chlorochromate, respectively. An established derivative of quinoline (Perfloxacin) had an MIC of 125-250 micrograms ml-1. The extinction time for 10(5) cfu in broth was 90 min for pyridinium chlorochromate and 120 min for quinolinium chlorochromate, except for B. subtilis which survived up to about 180 min and 360 min. A combination of the two compounds produced an antagonistic effect. The 50% lethal dose (LD50 toxicity) in mice was estimated at 76 micrograms g-1 and 33 micrograms g-1 body weight for the quinolinium and pyridinium chlorochromates. The compounds also exhibited some potential for suppressing a simulated staphylococcal infection in mice at the dosage levels of ca 22 micrograms g-1 for pyridinium chlorochromate and 45 micrograms g-1 for quinolinium chlorochromate.