Without more reliable solution, evaluation of airborne fungal spores is an essential tool to prevent fungal infections prevention and monitoring environmental colonization at hospital. Spores may be suspended during demolition and exposed immunocompromised patients to severe invasive aspergillosis (IA). One central block of the 32 blocks of Edouard Herriot (France) is being entirely demolished, while care activities continued in the near blocks. The aim of this study was to 1) evaluate the influence of meteorological parameters (MP) on airborne A. fumigatus conidia contamination variability indoor and outdoor hospital ward and 2) determine the A. fumigatus diversity and 3) to evaluate the correlation between environmental and clinical data.
Since February 2015, daily environmental survey of fungal loads was started in 8 wards located around the demolition site: 4 intensive care units (ICU), 1 unit of kidney and liver transplantation and 3 medical wards. Air sampling was realized indoor and outdoor selected wards with an agar impact sampler (Air-Ideal 90 mm, Biomérieux) by impaction onto Sabouraud Chloramphenicol agar. At each sample location 2 nutritive agars were realized and incubated 48h at 37°C for Aspergillus spp. identification and 5 days at 30°C for total fungal load count (TFL).
Furthermore outdoor was continuously monitored by volumetric sampler model Lanzoni VPPS-2000 (Bologna, Italy, Airtest) with a mean flow rate of 10 L.min-1. This sampler was placed on the roof of a block. Spores were impacted on adhesive tape and identified using a microscope. Aspergillaceae spores identified were expressed by spore/m3/day. Daily temperature, wind direction and speed, relative humidity were obtained from Meteociel® site. Genomic variability of A. fumigatus strains will be genotyping by Multiple–Locus Variable number tandem repeat Analysis (MLVA) technique. Susceptibility to antifungal will be tested using E-test® performed on RPMI buffered agar.
Until now, about 3200 air samples were realized. By the end of sampling period on December 2015, results of A. fumigatus, Aspergillus spp. and total fungal flora (TFL) collected outdoor with the agar impact sampler will be compared with the volumetric sampler data to see if it can further replace manual sampling. The evaluation of the impact of MP on outdoor and indoor fungal airborne contamination will be used to update recommendations for the preventing of IA during demolition. Genotype of environmental and clinical strains could be interesting to describe diversity of strains and eventually identification of probable transmission. Susceptibility to antifungal will permit us to estimate the proportion of azole resistance in environmental strains.
The growing impact of fungal infection and the extra cost related to antifungal curative therapy require the evaluation of adequacy of current technique of environmental monitoring in hospital. The first results obtained helped us to improve health protective measures and professional practice.