Structure of Pyrrolomycin B, A chlorinated nitro-pyrrole antibiotic.

We examined the antibacterial activity of MX in comparison with those of other CEPs, using aerobic Gram-positive cocci, aerobic Gram-negative bacilli and anaerobic bacteria, 870 strains in total, all isolated from clinical specimens, in 1979 and 1980. Against Streptococcus, CMX showed superior antibacterial activity than those of CFX, CMZ, CXM and CTM. Against H. influenzae, CMX also showed superior antibacterial activity than those of CFX, CMX, CXM, CTM and CEZ. ABPC-and PIPC-resistant strains were sensitive to CMX. CTX, CPZ and CZX also showed antibacterial activities equivalent to that of CMX. Against enteric bacteria, E. coli, Klebsiella, E. cloacae, Serratia, C. freundii and Proteus, CMX showed superior antibacterial activity than those of CFX, CMZ, CXM, CTM and CEZ. Especially, against E. coli, Klebsiella, P. mirabilis, P. rettgeri and P. inconstans, CMX showed strong antibacterial activity. As to non-fermentation bacteria, CMX's antibacterial activity was relatively weak except P. putrefaciens, Alcaligenes and Comamonas. However, it was superior than that of CEZ. In comparison with other CEPs, the strength of CMX varied according to the kinds of bacteria. As to anaerobic bacteria, CMX showed strong antibacterial activity against Peptococcus, Peptostreptococcus, Lactobacillus, Propionibacterium, C. perfringens, Veillonella and Fusobacterium. However, its antibacterial activity against Bacteroides was similar to those of other CEPs.