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.

Keywords::

• Antibiotic surveillance study
• Haemophilus influenzae isolates
• antibiotic resistance
• respiratory tract infections

Acknowledgements

We gratefully acknowledge the laboratory technicians from the Department of Medical Microbiology of Maastricht University Medical Centre. The members of the Antibiotic Resistance Surveillance Group are (participating centres from north to south): Dr K. Waar, Regional Public Health Laboratory Leeuwarden; Dr W.H.M. Vogels, Martini Hospital Groningen; Dr P. Bloembergen, Laboratory Zwolle; Dr A.J. Beunders, Public Health Laboratory Kennemerland Haarlem; Dr M.G.R. Hendrix, Laboratory of Microbiology Twente Achterhoek; Dr H.A. Bijlmer, Bronovo Hospital Den Haag; Dr B.M. Dejongh, St. Antonius Hospital Nieuwegein; Dr W.D.H. Hendriks, Medical Centre Rotterdam loc. Clara; Dr P. Sturm, University Medical Centre St. Radboud Nijmegen; Dr A.G.M. Buiting, St. Elisabeth Hospital Tilburg; Dr L.J.M. Sabbe, Regional Laboratory Zeeland Goes; Dr T.A.M. Trienekens, VieCuri Medical Centre Venlo; Dr H. van Dessel, Maastricht University Medical Centre.

Declaration of interest: The project was supported by the Dutch Working Group on Antibiotic Policy (SWAB).