Microbial yield from physiotherapy assisted sputum production in respiratory outpatients

Philip J. Langridge, Reyenna L. Sheehan, David W. Denning

Sputum is a key diagnostic sample for those with chronic chest conditions including chronic and allergic aspergillus-related disease, but often not obtained in clinic. The objective of this study was to evaluate physiotherapeutic interventions to obtain sputum from those not able to spontaneously produce and the subsequent microbiological result. Sputum samples were collected by physiotherapists from patients attending routine outpatient clinics managing their aspergillus-related diseases who were unable to spontaneously produce. Active Cycle of Breathing Techniques (ACBT) technique was applied first, for 10 min, followed by hypertonic saline induction using a Pari LC plus or Pari Sprint nebuliser, if necessary and deemed safe to do so. Samples processed in the laboratory using standard microbiological techniques for bacterial and fungal culture with the addition of Aspergillus real-time PCR. Samples were procured from 353 of 364 (97 %) patients, 231 (65 %) by ACBT and 119 (34 %) with administration of hypertonic saline. Three of 125 (2.4 %) patients had significant bronchospasm during sputum induction. Sixteen patients' sputum tested positive for Aspergillus culture, contrasting with 82 whose Aspergillus PCR was positive, 59 with a strong signal. PCR improved detection of Aspergillus by 350 %. Sputum from 124 (34 %) patients cultured other potentially pathogenic organisms which justified specific therapy. Physiotherapeutic interventions safely and effectively procured sputum from patients unable to spontaneously produce. The method for sputum induction was well-tolerated and time-efficient, with important microbiological results.