Canadian beta-lactamase-negative Haemophilus influenzae isolates showing decreased susceptibility toward ampicillin have significant penicillin binding protein 3 mutations

Diagn Microbiol Infect Dis. 2009 Apr;63(4):379-83. doi: 10.1016/j.diagmicrobio.2008.12.015. Epub 2009 Feb 26.

Abstract

Nineteen beta-lactamase-negative ampicillin-resistant (BLNAR) and 2 beta-lactamase-positive amoxicillin-clavulanic acid-resistant Canadian Haemophilus influenzae strains were characterized. All 21 isolates were found to have the N526K mutations in their ftsI genes, and their ampicillin MIC(50) values were 4-8 times that of beta-lactamase-negative ampicillin-susceptible strains. The difficulty in detection of BLNAR strains was discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Aged
  • Aged, 80 and over
  • Amino Acid Substitution / genetics
  • Amoxicillin-Potassium Clavulanate Combination / pharmacology
  • Ampicillin / pharmacology
  • Ampicillin Resistance*
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins / genetics*
  • Canada
  • Child, Preschool
  • DNA, Bacterial / genetics
  • Female
  • Haemophilus Infections / microbiology*
  • Haemophilus influenzae / drug effects*
  • Haemophilus influenzae / enzymology
  • Haemophilus influenzae / isolation & purification
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Mutation, Missense*
  • Penicillin-Binding Proteins / genetics*
  • beta-Lactamases / biosynthesis

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • DNA, Bacterial
  • Penicillin-Binding Proteins
  • Amoxicillin-Potassium Clavulanate Combination
  • Ampicillin
  • beta-Lactamases