Abstract: N-tetrazolyl beta-lactams of the Formula: ##STR1## and the pharmaceutically acceptable salts thereof wherein R.sup.2 is hydrogen, alkyl having 1 to 6 carbon atoms or carboalkoxy having 2 to 7 carbon atoms; andZ is ##STR2## and W is ##STR3## thus forming a zwitterion, or Z is ##STR4## wherein R.sup.1 is benzyl, phenyloxymethyl or ##STR5## wherein Y is alkoxy or substituted alkoxy having 1 to 6 carbon atoms wherein the substituent on the alkoxy group is --COOH; andW is ##STR6## wherein R.sup.3 is H, M or --CH.sub.2 COOM, wherein M is a pharmaceutically acceptable cation are disclosed. The compounds are useful as antibiotics.

Abstract: 3-Phosphonate carbapenems of the Formula: wherein R.sup.1 is hydrogen, alkyl, amino, --NHCO-alkyl, hydroxy, alkoxy, halo, hydroxyalkyl, carboxyl or trifluoromethyl; R.sup.2 is alkyl, substituted alkyl, heterocyclic or substituted heterocyclic; R.sup.3 is hydrogen, alkyl or substituted alkyl; and M is a metal cation of H.sup.+ are disclosed. The compounds are useful as antibiotics.

Abstract: Disclosed is the antibiotic 6-(1-hydroxyethyl)-2-substituted-thio-3-tetrazolyl-1-carbadethiapen-2-em and its pharmaceutically acceptable salts (I): ##STR1## wherein Z is C.sub.1 -C.sub.3 alkylamino, C.sub.1 -C.sub.3 alkylguanidino, C.sub.1 -C.sub.3 alkylamidino, or heterocycloalkyl and, M=H, a synthetically useful cation, or pharmaceutically acceptable cation. Such compounds as well as their pharmaceutically acceptable salts are useful as antibiotics. Also disclosed are processes for the preparation of such compounds; novel intermediates; pharmaceutical compositions comprising such compounds; and methods of treatment comprising administering such compounds and compositions when an antibiotic effect is indicated.