Abstract
The main purpose was to validate the use of outdoor-indoor volumetric impaction sampler with Hirst-type spore traps (HTSTs) to continuously monitor fungal load in order to prevent invasive fungal infections during major structural work in hospital settings. For 4 weeks, outdoor fungal loads were quantified continuously by 3 HTSTs. Indoor air was sampled by both HTST and viable impaction sampler. Results were expressed as particles/m3 (HTST) or colony-forming units (CFU)/m3 (biocollector). Paired comparisons by day were made with Wilcoxon’s paired signed-rank test or paired Student’s t-test as appropriate. Paired airborne spore levels were correlated 2 by 2, after log-transformation with Pearson’s cross-correlation. Concordance was calculated with kappa coefficient (κ). Median total fungal loads (TFLs) sampled by the 3 outdoor HTSTs were 3,025.0, 3,287.5 and 3,625.0 particles/m3 (P = 0.6, 0.6 and 0.3).—Concordance between Aspergillaceae fungal loads (AFLs, including Aspergillus spp. + Penicillium spp.) was low (κ = 0.2). A low positive correlation was found between TFLs sampled with outdoor HTST and indoor HTST with applying a 4-hour time lag, r = 0.30, 95% CI (0.23–0.43), P<0.001. In indoor air, Aspergillus spp. were detected by the viable impaction sampler on 63.1% of the samples, whereas AFLs were found by HTST-I on only 3.6% of the samples. Concordance between Aspergillus spp. loads and AFLs sampled with the 2 methods was very low (κ = 0.1). This study showed a 4-hour time lag between increase of outdoor and indoor TFLs, possibly due to insulation and aeraulic flow of the building. Outdoor HTSTs may permit to quickly identify (after 48 hours) time periods with high outdoor fungal loads. An identified drawback is that a too low sample area read did not seem to enable detection of Aspergillaceae spores efficiently. Indoor HTSTs may not be recommended at this time, and outdoor HTSTs need further study. Air sampling by viable impaction sampler remains the reference tool for quantifying fungal contamination of indoor air in hospitals.
Highlights
Environmental fungal contamination by moulds, such as Aspergillus spp., during major hospital renovation is a serious risk factor for outbreaks of nosocomial invasive fungal infections (IFI) in immunocompromised patients
Our objective was to assess the use of outdoor-indoor volumetric methods of air sampling by impaction with 7-day Hirst-type spore traps (HTST) [6,7], Two points were evaluated: (i) the correlation and concordance between fungal loads sampled with several outdoor HTSTs and between fungal loads sampled with outdoor and indoor HTSTs; (ii) the correlation and concordance between indoor fungal loads sampled with HTST and with a viable impaction sampler
Median total fungal loads (TFLs) sampled by the 3 outdoor HTSTs were 3,025.0 particles/m3 (2,056.3–4,381.3), 3,287.5 particles/m3 (1,768.8–5,768.8) and 3,625.0 particles/m3 (2,425.0–5,500.0) for HTST-O1, O2 and C, respectively (Fig 2)
Summary
Environmental fungal contamination by moulds, such as Aspergillus spp., during major hospital renovation is a serious risk factor for outbreaks of nosocomial invasive fungal infections (IFI) in immunocompromised patients. Air sampling is an interesting tool to check efficiency of barrier measures in order to prevent IFI in high-risk patients [3]. The reference tool for monitoring fungal loads in hospitals is currently the viable impaction sampler (biocollector) [4,5]. Air sampling is time-consuming, and results are obtained several days after sampling, as fungal colonies needs time to grow. If fungal load in air is increasing, the same time interval is needed to detect the increase and to implement adequate barrier measures for patients; in the meantime, patients have a higher risk to develop IFI. There is a need to develop new tools that provide real-time results of air fungal load
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
