Monitoring airborne fungi and bacteria in a major teaching hospital, Brisbane, Australia

Salonen, Heidi Johanna

Monday, March 19, 2012

Ground Floor (Cancun Center)

Heidi Johanna Salonen, Developing Indoor Environments, Finnish Institute Of Occupational Health, Helsinki, Finland

Luke Knibbs, International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia

Heidi Salonen, Developing Indoor Environments, Finnish Institute of Occupational Health, Helsinki, Finland

Chaminda Ranasinghe, Cell and Molecular Biosciences, Queensland University of Technology, Brisbane, Australia

Sam Clifford, International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia

Piotr Grzybowski, Faculty of Chemical and Process Engineering, Warsaw University of Technology, Warsaw, Poland

Scott Bell, School of Medicine, The University of Queensland, Brisbane, Australia

Congrong He, International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia

Megan Hargreaves, Cell and Molecular Biosciences, Queensland University of Technology, Brisbane, Australia

Lidia Morawska, International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, Australia

Introduction
Hospitals represent locations where an understanding indoor bioaerosols is an important component of ensuring appropriate air hygiene for patients and staff. This study aimed to determine the levels of indoor airborne fungi and bacteria in several locations within a large hospital and assess their correlation.

Methods
Samples of airborne fungi and bacteria were collected in an emergency department, respiratory patient ward, respiratory investigation unit, and an outpatient waiting room. Measurements were performed with an Andersen six-stage cascade impactor. Samples were collected on cetrimide agar plates. Measurements were conducted in the morning and afternoon on Monday-Thursday over three weeks in December, 2009. Statistical tests were carried out using the Student’s t-test and Analysis of Variance (ANOVA).

Results
Fungi and bacteria concentrations were greatest in the outpatient waiting room, and the arithmetic mean of bacteria concentration during individual sample periods ranged from 5.67 to 54.33 cfu/m3. The mean fungi levels ranged from 3.17 to 16.17 cfu/m3. The lowest levels were measured in respiratory patient ward, with mean bacteria levels from 2.50 to 23.83 cfu/m3 and fungi from 1.17 to 6.67 cfu/m3. Based on p-values associated with the ANOVA, there was no difference between the morning and afternoon levels of fungi and bacteria. The concentrations varied markedly over the sampling days, and we also observed spatial variation in concentrations, which was more pronounced for fungi than bacteria.

Discussion
Airborne microbe concentrations indoors generally vary temporally and spatially, and our initial results are in agreement with this. In our study, time of day had no statistically significant impact on fungi and bacteria concentrations. Instead, concentrations varied on each day of the week, and spatial variation was substantial. Room ventilation may be one key parameter that affected the concentrations we measured, and this and other factors will be investigated in our on-going analyses.

A1009 Monitoring airborne fungi and bacteria in a major teaching hospital, Brisbane, Australia