Cefsulodin sodium salt hydrate is a third generation β lactam antibiotic and member of the cephems subgroub of antibiotics. The compound displays a mechanism of action like many β lactam antibiotics through inhibition of cell wall synthesis by competitively inhibiting penicillin binding protein (PBP) crosslinking of peptidoglycan resulting in inhibition of the final transpeptidation step. Through the inability for Cefsulodin sodium salt hydrate to inhibit cefsulodin-resistant mutants of Pseudomonas aeruginosa PAO4089 growth displayed that Cefsulodin sodium salt hydrate may compete with PBP3 in addtion to PBP1A and PBP1B. Cefsulodin sodium salt hydrate is a third generation β lactam antibiotic and member of the cephems subgroub of antibiotics. The compound displays a mechanism of action like many β lactam antibiotics through inhibition of cell wall synthesis by competitively inhibiting penicillin binding protein (PBP) crosslinking of peptidoglycan resulting in inhibition of the final transpeptidation step. Through the inability for Cefsulodin sodium salt hydrate to inhibit cefsulodin-resistant mutants of Pseudomonas aeruginosa PAO4089 growth displayed that Cefsulodin sodium salt hydrate may compete with PBP3 in addtion to PBP1A and PBP1B. A β lactam antibiotic.