Risk factors for Stenotrophomonas maltophilia isolation from patients with cystic fibrosis

Abstract number: 1733_1031

Alexandrou-Athanasoulis H., Doudounakis S., Loucou I., Sergounioti A., Georgara M., Pangalis A.

The number of patients with cystic fibrosis (CF) whose airway secretions yielded Stenotrophomonas maltophilia (Sm) has been increasing during the last years.

The aim of our study is to determine risk factors for the initial recovery of Sm from respiratory secretions of patients with Cystic Fibrosis.

Material and Method: We reviewed retrospectively the clinical and laboratory data of 87 patients with CF who have been colonised with Sm between 01/2000 and 11/2006 and 87 matched controls of similar age (±1 yr) who never had a positive culture for Sm. Variables included age, gender, mean values of FEV as well as the use of oral, intravenous or inhaled antibiotics in the three months prior to the first isolation of S. maltophilia from airway secretions.

Results: (1) Eighty-seven out of the 428 patients who have attended our departments were found to be colonised with Sm. The incidence rate of Sm acquisition has increased from 3.6% in 2000 to 4.5% in 2006. (2) The mean age at the initial recovery of Sm was 6.9±4.6 years. (3) Patients positive for Sm were not found to have significantly worse spirometric values than Sm-negative matched controls. (4) Consumption of oral antibiotics (amoxicillin + clavulate/ciprofloxacin/macrolides) as well as the number of days on intravenous antibiotics were significantly higher in Sm-positive patients. (5) Treatment with inhaled antibiotics was not found to be a significant risk factor for Sm acquisition in our patients.

Conclusions: Patients with CF with Sm in their airway secretions do not have an overall worse clinical status at the time of initial Sm acquisition than Sm-negative patients. Although oral antibiotics or days of intravenous antibiotic therapy seems to be a significant risk factor for initial Sm acquisition the inhaled antibiotic therapy was not.