Airway Colonization with Resistant Microbiota: Can a Non-Invasive Ventilator be a Source of Cross-Infection?
Authors List
Olivia McGuiness1,3,4, Collette Menadue1,4, Sebastiaan Van Hal2,4, Rania Salama,3,5, Daniela Traini3,5, Amanda Piper1,3,4, Sheila Sivam1,3,4,
1. Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia
2. Department of Infectious Diseases, Royal Prince Alfred Hospital, Sydney, NSW, Australia
3. Woolcock Institute of Medical Research, Sydney, NSW, Australia
4. Faculty of Medicine and Health, University of Sydney, NSW, Australia
5. Faculty of Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie Park, NSW, Australia
Introduction
Non-invasive ventilators (NIV) are used to manage a wide range of patients with type 2 respiratory failure. It remains unclear if NIV devices are a possible reservoir for pathogens and if cleaning practices, in accordance with current manufacturer’s recommendations, are adequate in preventing cross-infection between patients when using these devices, particularly amongst patients colonised with difficult to treat airway microbiota. Patients with suppurative lung disease, like cystic fibrosis (CF) are at risk of colonising organisms which are difficult to eradicate and could preclude lung transplantation. In practice, NIV devices used in this population are carefully selected, avoiding use in other patients not colonised with similar microbes.
Objectives
We evaluated the possible presence of bacterial organisms on accessible surfaces and air samples from an NIV device used by a critically ill patient with CF, colonised with intermediate resistant Pseudomonas aeruginosa (PsA) and Methicillin Sensitive Staphylococcus aureus (MSSA). He last grew multi-resistant Mycobacterium abscessus (MAbs) 3 years prior and Burkholderia cepacia complex in his sputum 3 months prior.
Method
A ResMedTM Stellar 150 NIV device used for 7 hours immediately prior to intubation was assessed within 48 hours of use. The device was cleaned as recommended in the manufacturer’s clinical guide prior to the microbiological testing outlined below. The air inlet and outlet pathway were sampled using sterile moist cotton environmental sampling swabs, streaked onto growth media and incubated aerobically. Air samples were taken from bacterial viral filters within the circuit which were extracted, cut into two parts and added Middlebrook 7H9 broth to assess for mycobacterium species and to nutrient broth respectively. Samples were incubated aerobically for 48 hours at 37°C.
Results
No growth was demonstrated from either NIV surfaces or air samples.
Conclusions
We acknowledge the limitations of our experiment including the need to replicate these findings in a larger number of NIV devices, under controlled laboratory conditions using an Andersen Cascade Impactor and in devices that have been used for a longer duration for acute or chronic respiratory failure. While this experiment does not dispel the theoretical risk of cross-infection posed by portable ventilation equipment, it suggests that current cleaning practices may be adequate to allow re-use of devices by patients colonised with selected resistant microbiota with minimal risk of cross-infection.
Olivia McGuiness1,3,4, Collette Menadue1,4, Sebastiaan Van Hal2,4, Rania Salama,3,5, Daniela Traini3,5, Amanda Piper1,3,4, Sheila Sivam1,3,4,
1. Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia
2. Department of Infectious Diseases, Royal Prince Alfred Hospital, Sydney, NSW, Australia
3. Woolcock Institute of Medical Research, Sydney, NSW, Australia
4. Faculty of Medicine and Health, University of Sydney, NSW, Australia
5. Faculty of Medicine, Health and Human Sciences, Macquarie Medical School, Macquarie Park, NSW, Australia
Introduction
Non-invasive ventilators (NIV) are used to manage a wide range of patients with type 2 respiratory failure. It remains unclear if NIV devices are a possible reservoir for pathogens and if cleaning practices, in accordance with current manufacturer’s recommendations, are adequate in preventing cross-infection between patients when using these devices, particularly amongst patients colonised with difficult to treat airway microbiota. Patients with suppurative lung disease, like cystic fibrosis (CF) are at risk of colonising organisms which are difficult to eradicate and could preclude lung transplantation. In practice, NIV devices used in this population are carefully selected, avoiding use in other patients not colonised with similar microbes.
Objectives
We evaluated the possible presence of bacterial organisms on accessible surfaces and air samples from an NIV device used by a critically ill patient with CF, colonised with intermediate resistant Pseudomonas aeruginosa (PsA) and Methicillin Sensitive Staphylococcus aureus (MSSA). He last grew multi-resistant Mycobacterium abscessus (MAbs) 3 years prior and Burkholderia cepacia complex in his sputum 3 months prior.
Method
A ResMedTM Stellar 150 NIV device used for 7 hours immediately prior to intubation was assessed within 48 hours of use. The device was cleaned as recommended in the manufacturer’s clinical guide prior to the microbiological testing outlined below. The air inlet and outlet pathway were sampled using sterile moist cotton environmental sampling swabs, streaked onto growth media and incubated aerobically. Air samples were taken from bacterial viral filters within the circuit which were extracted, cut into two parts and added Middlebrook 7H9 broth to assess for mycobacterium species and to nutrient broth respectively. Samples were incubated aerobically for 48 hours at 37°C.
Results
No growth was demonstrated from either NIV surfaces or air samples.
Conclusions
We acknowledge the limitations of our experiment including the need to replicate these findings in a larger number of NIV devices, under controlled laboratory conditions using an Andersen Cascade Impactor and in devices that have been used for a longer duration for acute or chronic respiratory failure. While this experiment does not dispel the theoretical risk of cross-infection posed by portable ventilation equipment, it suggests that current cleaning practices may be adequate to allow re-use of devices by patients colonised with selected resistant microbiota with minimal risk of cross-infection.
