Rationale for treating community-acquired lower respiratory tract infections with amoxicillin/sulbactam combination through pharmacodynamic analysis in the setting of aminopenicillin-resistant organisms

J Chemother. 2001 Aug;13(4):402-6. doi: 10.1179/joc.2001.13.4.402.

Abstract

In order to establish a rationale for treating community-acquired lower respiratory tract infections, we assess here the pharmacodynamics of amoxicillin/sulbactam, 500mg/500mg, a formulation marketed in Argentina since 1988 and currently available in 17 countries, against the major pathogens, in comparison with that of a novel formulation (875mg/125mg, see J Chemother 2000; 12: 223-227). In time-kill studies, both bactericidal and inhibitory activity were seen in the 1.5- and 6-h sera, obtained from 12 volunteers after a single oral dose, against both a penicillin-susceptible and an -intermediate Streptococcus pneumoniae strain, as well as against Moraxella catarrhalis and a beta-lactamase-negative Haemophilus influenzae strain. Only the 1.5-h sera proved bactericidal against a penicillin-resistant S. pneumoniae strain (MIC, 2 microg/ml) and a beta-lactamse-positive H. influenzae isolate. This study suggests that amoxicillin/sulbactam (500mg/500mg) is still a suitable option for treating community-acquired lower respiratory tract infections, allowing a b.i.d. dosing schedule. Caution should be taken with pneumonia caused by beta-lactamase-positive H. influenzae or penicillin-resistant (MIC > or =2 microg/ml) S. pneumoniae isolates. Either shorter dosing intervals (t.i.d.) or a higher amoxicillin content in the formulation (i.e. 875 mg) may be required in these situations.

MeSH terms

  • Administration, Oral
  • Adult
  • Amoxicillin / pharmacology
  • Community-Acquired Infections / drug therapy*
  • Community-Acquired Infections / microbiology
  • Drug Therapy, Combination / pharmacology*
  • Female
  • Haemophilus influenzae / drug effects*
  • Haemophilus influenzae / isolation & purification
  • Humans
  • Male
  • Microbial Sensitivity Tests
  • Moraxella catarrhalis / drug effects*
  • Moraxella catarrhalis / isolation & purification
  • Penicillin Resistance
  • Pneumonia, Bacterial / drug therapy*
  • Pneumonia, Bacterial / microbiology
  • Serum Bactericidal Test
  • Streptococcus pneumoniae / drug effects*
  • Streptococcus pneumoniae / isolation & purification
  • Sulbactam / pharmacology

Substances

  • Amoxicillin
  • Sulbactam