Stenotrophomonas maltophilia in cystic fibrosis: serologic response and effect on lung disease.
BACKGROUND
Stenotrophomonas maltophilia is one of the more common multidrug-resistant organisms isolated from the respiratory tract of patients with cystic fibrosis (CF), but the effect of chronic S. maltophilia infection on CF lung disease is unknown.


OBJECTIVE
To determine the impact of chronic S. maltophilia infection on lung disease in CF.


METHODS
We developed a serologic assay specific for S. maltophilia and in a cross-sectional study, measured serum antibodies to S. maltophilia in patients with CF to determine if a definition of chronic S. maltophilia isolation based on culture results corresponded to an immunologic response (serologic study). We then used this validated definition to examine the effect of chronic S. maltophilia on the severity of lung disease in a retrospective cohort study using the Toronto CF Database from 1997-2008 (cohort study).


RESULTS
Serum antibody levels to S. maltophilia were measured in 179 patients with CF. Patients with chronic S. maltophilia had significantly higher mean antibody levels to S. maltophilia flagellin (P < 0.0001) and whole cell (P = 0.0004) compared with patients with intermittent or no S. maltophilia. The cohort study included 692 patients with an average follow-up of 8.3 years. In an adjusted log linear model, patients with chronic S. maltophilia infection had a significantly increased risk of pulmonary exacerbation requiring hospitalization and antibiotics compared with patients who had never had S. maltophilia (relative risk = 1.63; P = 0.0002).


CONCLUSIONS
Chronic S. maltophilia infection in patients with CF is associated with a specific immune response to this organism and is an independent risk factor for pulmonary exacerbations.
Waters
Valerie
V
Division of Infectious Diseases, Department of Pediatrics, Hospital for Sick Children, Toronto, ON, Canada. valerie.waters@sickkids.ca
Yau
Yvonne
Y
Prasad
Sudha
S
Lu
Annie
A
Atenafu
Eshetu
E
Crandall
Ian
I
Tom
Stephanie
S
Tullis
Elizabeth
E
Ratjen
Felix
F
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D000907:Antibodies, Bacterial / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000097:blood / Q000276:immunology* / Q000382:microbiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D016905:Gram-Negative Bacterial Infections / Q000097:blood* / Q000276:immunology* / Q000382:microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D020615:Stenotrophomonas maltophilia / Q000276:immunology* / Q000302:isolation & purification; D055815:Young Adult
D000907:Antibodies, Bacterial