Increase in Quinolone Resistance in a Haemophilus Influenzae Strain Isolated From a Patient With Recurrent Respiratory Infections Treated With Ofloxacin

Antimicrob Agents Chemother. 1999 Jan;43(1):161-2.


The increase in the level of quinolone resistance of Haemophilus influenzae clinical isolates during ofloxacin therapy of a patient with recurrent respiratory infections was investigated. The first isolate (MIC of ciprofloxacin of 2 microg/ml) and the second isolate (MIC of 32 microg/ml) belonged to the same clone, as shown by pulsed-field gel electrophoresis, and the increase in the resistance level was associated with a substitution in Ser-84 to Arg in the ParC protein. These results emphasize the potential risk of development of quinolone-resistant H. influenzae during fluoroquinolone therapy in patients with recurrent respiratory infection.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Anti-Infective Agents / pharmacology*
  • Anti-Infective Agents / therapeutic use
  • DNA Topoisomerase IV
  • DNA Topoisomerases, Type II / genetics
  • DNA Topoisomerases, Type II / metabolism
  • Female
  • Haemophilus Infections / drug therapy
  • Haemophilus Infections / genetics
  • Haemophilus Infections / microbiology*
  • Haemophilus influenzae / drug effects*
  • Haemophilus influenzae / isolation & purification
  • Haemophilus influenzae / metabolism
  • Humans
  • Microbial Sensitivity Tests
  • Middle Aged
  • Mutation
  • Ofloxacin / pharmacology*
  • Ofloxacin / therapeutic use
  • Polymerase Chain Reaction
  • Recurrence
  • Respiratory Tract Infections / drug therapy
  • Respiratory Tract Infections / microbiology*


  • Anti-Infective Agents
  • Ofloxacin
  • DNA Topoisomerase IV
  • DNA Topoisomerases, Type II