CF airborne cross-infection risk extended

Cystic fibrosis

By Mardi Chapman

2 May 2018

Gram-negative bacteria and Staphylococcus aureus in the sputum of patients with cystic fibrosis can travel up to four metres during coughing and remain viable for up to 45 minutes.

The findings suggest that person-to-person transmission of the organisms is possible, similar to more common pathogens in cystic fibrosis such as Pseudomonas aeruginosa and Mycobacterium abscessus.

The Queensland study in a small group of 30 patients with a history of infection found the bacteria could be isolated in the majority of cough aerosol samples.

61% of gram-negative organisms including S. maltophilia, Achromobacter and Burkholderia spp. could be cultured at four metres and 53% at 45 mins after extraction.

“…whereas for the S.aureus group, 8/16 (50.0%) had viable aerosol at 4m and 4/16 (25%) at 45 min, with no significant difference in the number of bacterial CFUs between the groups at any distance or duration.”

Each organism detected in cough aerosols was an identical genotype to an organism in the paired sputum sample.

The authors said their findings highlight the importance of universal infection control practices for all people with cystic fibrosis.

“As found in our earlier cough aerosol studies with P. aeruginosa an association between aerosol CFUs and sputum CFU concentrations for GNB and S. aureus has been demonstrated, suggesting those with a higher burden of microbial load in the sputum may pose a greater risk of airborne transmission.”

“Taken together, these data provide further support for surgical mask wear to minimise potential cross-infection within CF healthcare facilities.”

 

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