title: Antimicrobial resistance among respiratory Haemophilus influenzae isolates from pulmonology services over a six-year period.
abstract: BACKGROUND
  Respiratory tract infections (RTI) are frequently caused by Haemophilus influenzae. Widespread antibacterial resistance among respiratory microorganisms complicates empirical RTI treatment. Therefore, national data on antibiotic resistance for H. influenzae are important for guiding optimal antibiotic choice.
  
  
  METHODS
  The antibiotic susceptibility of H. influenzae strains isolated from respiratory specimens of patients admitted to the pulmonology services between 2005 and 2010 was assessed. Isolates were collected annually from 13 hospitals in the Netherlands as part of the national intramural antimicrobial resistance surveillance performed by the Dutch Working Group on Antibiotic Policy (SWAB). Breakpoints for resistance were in accordance with the criteria of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Trend analysis was performed using logistic regression analysis.
  
  
  RESULTS
  In total, 1606 H. influenzae strains were analyzed. The prevalence of antibiotic resistance to amoxicillin, co-amoxiclav, doxycycline, co-trimoxazole, and clarithromycin was stable over the 6-y period, and there was a trend towards a decrease in the prevalence of beta-lactamase-producing isolates. Regarding prevalences, no significant trends were observed.
  
  
  CONCLUSIONS
  Our study showed no significant changes in antibiotic resistance for H. influenzae isolated at different hospitals in the Netherlands over a 6-y period. Regular surveillance remains important in controlling the prevalence of resistance, since actual resistance data should be taken into account when the choice of an empiric antibiotic is made.
authors.affiliation: Department of Medical Microbiology, Research Institute NUTRIM, Maastricht University Medical Centre, the Netherlands.
authors.forename: Tanja H
authors.initials: TH
authors.lastname: Geelen
authors.forename: Frank R
authors.initials: FR
authors.lastname: Stassen
authors.forename: Jacomina A A
authors.initials: JA
authors.lastname: Hoogkamp-Korstanje
authors.forename: Cathrien A
authors.initials: CA
authors.lastname: Bruggeman
authors.forename: Ellen E
authors.initials: EE
authors.lastname: Stobberingh
mesh_terms: D000328:Adult; D024881:Drug Resistance, Bacterial; D005260:Female; D006192:Haemophilus Infections / Q000453:epidemiology / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000302:isolation & purification; D006761:Hospitals; D006801:Humans; D015994:Incidence; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D015272:Pulmonary Medicine; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000382:microbiology*