For use in the treatment of the following infections when caused by susceptible strains of the designated microorganisms: (1) uncomplicated urinary tract infections caused by Escherichia coliand Proteus mirabilis, (2) otitis media caused by Haemolus influenzae (beta-lactamase positive and negative strains), Moraxella catarrhalis (most of which are beta-lactamase positive), and S. pyogenes, (3) ryngitis and tonsillitis caused by S. pyogenes, (4) acute bronchitis and acute exacerbations of chronic bronchitis caused by Streptococcus pneumoniae and Haemolus influenzae (beta-lactamase positive and negative strains), and (5) uncomplicated gonorrhea (cervical/urethral) caused by Neisseria gonorrhoeae (penicillinase- and non-penicillinase-producing strains).