Cystic Fibrosis (CF) Lower Respiratory Culture
For the isolation and identification of microörganisms associated with pulmonary disease in patients with cystic fibrosis
Sputum culture results from patients with CF have been shown to correlate well with the presence of microörganisms in the lower airways. The number of microbial species associated with CF lung disease is relatively limited. Emphasis is placed on the recovery of these organisms, including mucoid and nonmucoid Pseudomonas aeruginosa, Staphylococcus aureus, Burkholderia cepacia complex (which includes B cepacia genomovars I, III, and VI; Burkholderia multivorans; Burkholderia stabilis; Burkholderia vietnamiensis; Burkholderia ambifaria; Burkholderia anthina; and Burkholderia pyrrocinia), Burkholderia gladioli, Ralstoniapickettii, Ralstonia mannitolilytica, Stenotrophomonas maltophilia, Achromobacter species, other nonglucose-fermenting, gram-negative rods, Haemophilus influenzae and Streptococcus pneumoniae.
Screening of sputa for specimen quality based on Gram stain evaluation is not appropriate since limited organisms are associated with CF lung disease and their presence on culture is considered clinically significant regardless of Gram stain findings. Specimens from CF patients will grow potential pathogens >90% of the time, although approximately 40% would be rejected based on the Gram stain evaluation.
Sputum, endotracheal aspirate, bronchoalveolar lavage (BAL), bronchial brushing, transbronchial biopsy, deep pharyngeal swab
5 to 10 mL sputum, 10 to 50 mL lavage fluid, 5 mL bronchial washing, one swab
Sterile screw-cap container (preferred) or bacterial swab transport system. Label container as obtained from a CF patient.
For sputum collection, the patient should be instructed to remove dentures, rinse mouth, and gargle with water. Instruct the patient to cough deeply and expectorate sputum into proper container. Be sure the patient understands the difference between sputum and saliva.
Sputum: The patient should brush his/her teeth and/or rinse mouth well with water before attempting to collect the specimen, in order to reduce the possibility of contaminating the specimen with food particles, oropharyngeal secretions, etc. Instruct the patient that only a specimen brought forth by deep cough should be expectorated into the container. After the specimen has been collected, it should be examined to make sure it contains a sufficient quantity (at least 1 mL) of thick mucus (not saliva). Only the screw-cap container should be submitted to the laboratory.
Deep pharyngeal swab (cough or gagged throat specimen): Place a plastic shaft polyester- or rayon-tipped swab in the back of the throat and induce coughing. Remove the swab when coughed secretions have been collected on the swab. Place swab in plastic transport sleeve containing preservative medium and submit to the laboratory.
Note: This technique is used in those CF patients who are unable to produce sputum.
Refrigerate at 2°C to 8°C.
Unlabeled specimen or name discrepancy between specimen and test request label; inappropriate specimen transport device; leaking specimen; specimen received after prolonged delay (usually >72 hours); expired transport