During the isolation and purification of PS-5, PS-6 and PS-7 (PS-group of carbapenem compounds) from the culture broths of Streptomyces cremeus subsp. auratilis A 271, we have discovered a new minor component designated PS-8. Same as other carbapenem antibiotics, PS-8 possesses an excellent antimicrobial activity against Grampositive and Gram-negative bacteria as well as a potent β-lactamase-inhibitory property.