Antimicrobial resistance in Haemophilus influenzae from England and Scotland in 1991

J Antimicrob Chemother. 1992 May;29(5):547-54. doi: 10.1093/jac/29.5.547.


Twenty-two laboratories in England and Scotland sent 2212 clinical isolates of Haemophilus influenzae to The London Hospital Medical College (LHMC) between 1 January and 31 March 1991. After confirmation of identity, the prevalence of resistance was determined and compared with results from previous similar surveys. beta-Lactamase was produced by 8.3% of non-capsulate isolates and 21% of 52 type b isolates; both figures were higher than the 6% and 18% figures recorded, respectively, in 1986. There was an increase in the prevalence of non-beta-lactamase-mediated diminished susceptibility to ampicillin (5.8%) and co-amoxiclav (6.1%) compared with 1986 (4%). Whereas fewer H. influenzae isolates were resistant to tetracycline (1.4%) or chloramphenicol (0.8%), there was an increase in resistance to trimethoprim (6.8%) and to sulphamethoxazole (16.9%) compared with 1986 (4.2% and 3.5% respectively). In addition, 95 isolates (4.3%) were resistant to both of these anti-folate antimicrobials. Six isolates (one type b from CSF) were resistant to all drugs tested, except for co-amoxiclav. Overall, the results demonstrated that changes have occurred in the last decade in England and Scotland, such that H. influenzae isolates are increasingly likely to be resistant to ampicillin, co-amoxiclav and co-trimoxazole.

Publication types

  • Comparative Study

MeSH terms

  • Chloramphenicol Resistance
  • Drug Resistance, Microbial*
  • Haemophilus influenzae / drug effects*
  • Haemophilus influenzae / enzymology
  • Haemophilus influenzae / physiology
  • Humans
  • Microbial Sensitivity Tests
  • Respiratory Tract Infections / microbiology
  • Sulfamethoxazole / pharmacology
  • Tetracycline Resistance
  • Trimethoprim Resistance
  • beta-Lactamases / physiology


  • beta-Lactamases
  • Sulfamethoxazole