Molecular epidemiology of Pseudomonas aeruginosa in an unsegregated bronchiectasis cohort sharing hospital facilities with a cystic fibrosis cohort

Abstract

While (PA) cross-infection is well documented among patients with cystic fibrosis (CF), the equivalent risk among patients with non-CF bronchiectasis (NCFB) is unclear, particularly those managed alongside patients with CF. We performed analysis of PA within a single centre that manages an unsegregated NCFB cohort alongside a segregated CF cohort. We found no evidence of cross-infection between the two cohorts or within the segregated CF cohort. However, within the unsegregated NCFB cohort, evidence of cross-infection was found between three (of 46) patients. While we do not presently advocate any change in the management of our NCFB cohort, longitudinal surveillance is clearly warranted.

Transmission of bacteria in bronchiectasis and chronic obstructive pulmonary disease: Low burden of cough aerosols

“…Our results found that no major Australian CF shared P. aeruginosa strains were detected in our current cohort. In fact, our study found no evidence of shared P. aeruginosa strain infections, which is in keeping with the published data that shared P. aeruginosa strains are uncommon in patients with bronchiectasis or COPD . The P. aeruginosa strains detected in our study are commonly found in other niches, such as the natural environment and non‐CF infections .…”

“…Our study demonstrates that patients with bronchiectasis and COPD can release aerosols containing viable P. aeruginosa during coughing; however, no shared strains of P. aeruginosa respiratory infection were detected in study participants. Our results support the published data that cross-infection of P. aeruginosa affects a minority of patients with bronchiectasis [14][15][16] and provides much needed evidence to understanding cross-infection in bronchiectasis, which was highlighted as a research priority in a recent review. 30 Whilst we have demonstrated that aerosol transmission is an unlikely transmission route, it is worth noting that the participants selected for the study were all low producers 26 of P. aeruginosa cough aerosols and also that the study participants had very few opportunities for transmission events to occur during hospital visits, thus reducing the risk of potentially being exposed to each other's cough aerosols.…”

“…In fact, our study found no evidence of shared P. aeruginosa strain infections, which is in keeping with the published data that shared P. aeruginosa strains are uncommon in patients with bronchiectasis or COPD. [14][15][16][17]19,20 The P. aeruginosa strains detected in our study are commonly found in other niches, such as the natural environment and non-CF infections. 3,6,14,33 Our longitudinal analysis of P. aeruginosa isolates showed that the majority of participants retained the same unique P. aeruginosa strain over time, which is consistent with other recent studies.…”

“…13 Yet, unlike CF, cross-infection with P. aeruginosa is reported to be uncommon in patients with bronchiectasis and COPD. [14][15][16][17][18][19][20] Although the evidence for crossinfection is infrequent in non-CF suppurative lung diseases, 15,16 the transmission mechanism of possible person-to-person transmission events has not been studied previously. Therefore, we sought to determine if (i) patients with bronchiectasis or COPD can produce cough aerosols containing P. aeruginosa and (ii) if respiratory infections with shared P. aeruginosa strains occur in patients with bronchiectasis and COPD attending a centre that is co-located with a large adult CF centre.…”

“…In (non‐CF) bronchiectasis and chronic obstructive pulmonary disease (COPD), P. aeruginosa predominantly causes infection in those with severe disease and is associated with poorer prognosis, higher mortality and increased hospital admissions . Yet, unlike CF, cross‐infection with P. aeruginosa is reported to be uncommon in patients with bronchiectasis and COPD . Although the evidence for cross‐infection is infrequent in non‐CF suppurative lung diseases, the transmission mechanism of possible person‐to‐person transmission events has not been studied previously.…”