Respiratory samples

Coliforms in sputum are most often colonising the upper respiratory tract, and not true pathogens. The commonest scenario would be after a recent course of antibiotics, where the normal upper respiratory tract flora has been disrupted.  This does not require treatment with further antibiotics.

Patient groups where the coliform cultured may be significant and require treatment include those with severe underlying lung disease e.g. bronchiectasis, immunosuppressed patients or patients for whom a hospital acquired pneumonia (HAP) is clinically suspected.

Similar to coliforms, Pseudomonas spp in sputum is most often colonising. The commonest scenario would be after a recent course of antibiotics, where the normal upper respiratory tract flora has been disrupted.

Patient groups where a Pseudomonas may be significant and require treatment include those with severe underlying lung disease e.g. bronchiectasis, immunosuppressed patients or patients for whom a hospital acquired pneumonia (HAP) is clinically suspected.

Growth of candida from sputum/respiratory tract samples (without clinical evidence of thrush) most commonly indicates colonisation and does not require treatment.

The significance of isolating Aspergillus spp in sputum samples depends on the immune status of the patient. In immunocompetent patients, isolation of Aspergillus spp from the sputum almost always represents colonisation. 

Isolation of Aspergillus spp in immunocompromised patients (and a small percentage of immunocompetent patients) may be associated with clinical infection and further investigations would be warranted.