Evolution of H. influenzae resistance in a chest diseases hospital, for the period 2001–2006

Abstract number: 1733_1371

Tsagarakis N., Gioga A., Makarona M., Moraitou H., Kentrou N., Panagi M., Pefanis A., Damianidou S., Kanavaki S.

Objectives: The aim of this study was to investigate the resistance patterns of H. influenzae, from strains isolated in `Sotiria' Chest Diseases Hospital of Athens, within the period September 2001 to September 2006.

Material and Methods: 700 H. influenzae strains were isolated from respiratory samples (sputum and bronchial secretions). The culture and antibiotic susceptibility tests (Kirby-Bauer) were performed according to NCCLS 2004 guidelines, including the following antibiotics: ampicillin, amoxicillin/clavulanic acid, cefalothin, cefuroxime, erythromycin, co-trimoxazole, tetracycline and ciprofloxacin. The b-lactamase production was tested with nitrocefine disks (OXOID, UK).

Results: Among all isolates: 152/700 strains were b-lactamase positive (21.7%), while a gradual increase of the percentage of b-lactamase positive strains was noted from 2001 (10.9%) to 2006 (27.93%). 167/700 strains were ampicillin-resistant (23.8%). The percentage of the ampicillin-resistant strains was gradually increased from 10.9% in 2001–02 to 29.73% in 2005–06. Within the total of ampicillin-resistant strains, 152/167 (91%) were b-lactamase positive (BLPAR), whereas 15/167 (9%) were b-lactamase negative (BLNAR). A consistent increase of the percentage of BLNAR strains is noted from 0% in 2001–02, to 9% in 2005–06. A low rate of ciprofloxacin resistance was noted for the study period (0.9%). The percentage of the strains resistant to erythromycin was almost doubled from 49.5% in 2001–02 to 90.01% in 2005–06

Conclusions: It is interesting that the prevalence of b-lactamase positive H. influenzae isolates has been significantly increased (3×) and BLNAR strains have also emerged throughout the decade. In addition, erythromycin resistance is of great concern, since it has been double raised recently.

The evolution of H. influenzae resistant patterns should be taken under consideration, when empiric antibiotic treatment is offered for upper respiratory system infections.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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