Abstract: Broad spectrum beta-lactamase inhibitors. Certain inhibitors also exhibit potent antibiotic activity in addition to beta-lactamase inhibition. Compounds of the invention are designed such that on cleavage of the beta-lactam ring reactive moieties are generated which can inactivate beta-lactamase. Compounds of the invention include those of formula: and pharmacologically acceptable salts thereof where variables Z, Y, M, y, n, R, R4, R5, R1 and R2 are as defined in the specification. M most generally represents a chemical moiety which is in conjugation with the nitrogen of the core beta-lactam ring system of the compound, such that one or more reactive species, e.g., electrophilic or nucleophilic sites are generated on modification of M which is initiated by cleavage of the beta-lactam ring. Also provided are methods of making beta-lactamase inhibitors and beta-lactam antibiotics exhibiting such inhibition.