THIRD-GENERATION CEPHALOSPORIN - Most third-generation cephalosporins have a high degree of stability in the presence of beta-lactamase (penicillinase and cephalosporinase), and, therefore, they have excellent activity against a wider spectrum of gram-negative bacteria, including penicillinase-producing strains of N. gonorrhoeae and most Enterobacteriaceae (E. coli, Citrobacter, Enterobacter, Klebsiella, Morganella, Proteus, Providencia, and Serratia species). Third-generation cephalosporins include cefixime, cefoperazone, cefotaxime, cefpodoxime, ceftazidime, ceftizoxime, and ceftriaxone.