Activity of moxalactam and cefotaxime alone and in combination with ampicillin or penicillin against group B streptococci

Antimicrob Agents Chemother. 1981 May;19(5):794-7. doi: 10.1128/AAC.19.5.794.

Abstract

The activities of moxalactam and cefotaxime, alone and combined with ampicillin or penicillin, against 40 isolates of group B streptococci were assessed by using the microtiter broth dilution, checkerboard, and time-kill techniques. Penicillin and cefotaxime were bactericidal for all isolates at concentrations of 0.06 micrograms/ml or less. Ampicillin was slightly less active. Moxalactam was bactericidal for all strains at concentrations of 4 to 8 micrograms/ml. The ampicillin- moxalactam combination was partially synergistic for 60% of the isolates tested; the ampicillin-cefotaxime combination was partially synergistic for 35% of these isolates. No instances of antagonism were observed. In time-kill evaluations, ampicillin (3.0 micrograms/ml) and penicillin (0.75 micrograms/ml) effected 2.5 to 3.5 log10 reductions in numbers of colony-forming units. The addition of 4 micrograms of cefotaxime per ml or 8 to 16 micrograms of moxalactam per ml to penicillin or ampicillin did not alter killing kinetics. Moxalactam and cefotaxime neither enhanced nor decreased the activity of ampicillin or penicillin against group B streptococci.

Publication types

  • Comparative Study

MeSH terms

  • Ampicillin / pharmacology*
  • Cefotaxime / pharmacology*
  • Cephalosporins / pharmacology*
  • Cephamycins / pharmacology*
  • Drug Synergism
  • Humans
  • Moxalactam
  • Penicillin G / pharmacology*
  • Penicillin Resistance
  • Streptococcal Infections / microbiology
  • Streptococcus agalactiae / drug effects*
  • Streptococcus agalactiae / growth & development

Substances

  • Cephalosporins
  • Cephamycins
  • Ampicillin
  • Cefotaxime
  • Penicillin G
  • Moxalactam