Lower Respiratory Culture, Other Than Expectorated Sputum

Aspirates, biopsy, tissue, bronchial washing

1 g tissue, 10 to 50 mL lavage fluid, 5 mL bronchial washing

Sterile screw-cap container

In bronchoscopy and aspirated specimens reduction of contamination may be accomplished by a head-down position to reduce gravitational flow of saliva. Oral contamination may successfully be reduced by using a telescoping double catheter with a plug to protect the brush or a sheathed brush. The use of the telescoping plugged catheter (TPC) and bronchoalveolar lavage (BAL) increases the overall diagnostic yield, however, a high frequency of false-positives, circa 25%, is a drawback. Bronchial washings are unfortunately commonly diluted with topical anesthetics, which are bacteriostatic, and with irrigating solutions. If anaerobic bacteria are suspected in a transtracheal aspiration, a properly collected specimen for anaerobic culture should be submitted.

Culture

Potential pathogens recovered by usual culture methods include Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus parainfluenzae, Pseudomonas aeruginosa, Escherichia coli, Proteus sp, Moraxella catarrhalis, and (rarely) many other organisms. Haemophilus sp and Neisseria sp may not be routinely isolated and identified. Thus, if their presence is clinically suspected, they should be specifically requested.

Agents such as Bordetella pertussis, Chlamydia pneumoniae, Corynebacterium diphtheriae, Legionella pneumophila, Mycoplasma pneumoniae, and Mycobacterium tuberculosis require special laboratory measures for isolation. Clinical suspicion of involvement by these agents should be communicated to the laboratory.