title: Studies on beta-lactam antibiotics V. Effect on antimicrobial activity of 2- and/or 3-methyl group (S) in a cephem nucleus.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D055598:Chemical Phenomena; D002621:Chemistry; D004926:Escherichia coli / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D013329:Structure-Activity Relationship; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D047090:beta-Lactams