Risk of bacterial cross infection associated with inspiration through flow-based spirometers.
BACKGROUND
Bacterial contamination of spirometers has been documented in water-sealed devices, mouthpieces, and connection tubes. Little information is available about bacterial contamination of flow-based apparatuses such as turbine-type spirometers and pneumotachographs. Inspiration through contaminated equipment is a potential source of cross infection. To investigate bacteria mobilization (ie, bacteria detachment and aerosolization from the instrument) during routine spirometric testing, 2 types of flow-based spirometers were used. Bacteria mobilization during artificial inspiration through in-line filters or cardboard mouthpieces was evaluated.


METHODS
Nine hundred workers undergoing periodic spirometric testing were enrolled at the occupational physician office in 30 sessions of 30 subjects each. The participants were asked to perform a forced vital capacity test in a turbine-type spirometer and in an unheated pneumotachograph fitted with disposable in-line filters or cardboard mouthpieces. To evaluate bacterial mobilization, an artificial inspiration was performed and bacterial growth determined. The bacterial growth analysis was assessed after the first and the thirtieth spirometric tests of each session without disinfecting the instruments between tests. In addition, instrument bacterial contamination was evaluated.


RESULTS
No significant bacterial mobilization and instrument contamination were found in spirometric tests executed with in-line filters. Conversely, a significant bacterial mobilization and instrument contamination were observed in tests performed with cardboard mouthpieces. Differences between the 2 spirometers were not significant.


CONCLUSIONS
In-line filters may effectively reduce the risk of bacterial cross infection. Inspiration through flow-based spirometers fitted with disposable cardboard mouthpieces is completely safe when combined with spirometer disinfection/sterilization between subjects.
Bracci
Massimo
M
Department of Molecular Pathology and Innovative Therapies, Occupational Medicine, Polytechnic University of Marche, Via Tronto 10/a, Torrette, Ancona, Italy. m.bracci@email.it
Strafella
Elisabetta
E
Croce
Nicola
N
Staffolani
Sara
S
Carducci
Annalaura
A
Verani
Marco
M
Valentino
Matteo
M
Santarelli
Lory
L
D000328:Adult; D001419:Bacteria / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000517:prevention & control*; D003428:Cross Infection / Q000517:prevention & control*; D004864:Equipment and Supplies / Q000382:microbiology*; D006801:Humans; D008875:Middle Aged; D018570:Risk Assessment; D013147:Spirometry / Q000009:adverse effects*