Queen and worker policing in the monogynous and monandrous ant

Novel cephalosporins shown by the general formula: wherein Y is an acyloxy group, a quaternary ammonium group or a group of the formula: -S-R in which R is a nitrogen-containing heterocyclic group, and pharmaceutically acceptable salts thereof have high antibacterial properties against Gram-positive and Gram-negative bacteria including Pseudomonas aeruginosa and Serratia marcescens.