A 10-year survey of fungal aerocontamination in hospital corridors: a reliable sentinel to predict fungal exposure risk?

BACKGROUND

Invasive mould infections represent a threat for high-risk patients hospitalized in haematology units. French guidelines recommend that fungal aerocontamination monitoring should be performed quarterly. Since 2002, Besançon University Hospital has expanded to include several new buildings. Consequently, environmental surveys have been re-inforced and are now performed on a weekly basis.

AIM

To retrospectively assess the contribution of fungal aerocontamination measurement in haematology corridors and main hospital corridors as a sentinel to assess fungal exposure and risk of invasive mould infections.

METHODS

Over a 10-year period, 2706 air samples were taken by impaction every week in the same locations in haematology corridors and main hospital corridors. All fungal species were identified. The Haematology and Hospital Hygiene Departments were alerted systematically whenever a peak of opportunistic species was detected and corrective action was planned. Since 2007, each case of invasive aspergillosis has been reported to the French health authorities. Cuzick's test, Mann-Kendall's trend test, autocorrelation and Spearman's correlation rank test were used for statistical analysis.

FINDINGS

Over 10 years of surveillance, 12 peaks of Aspergillus fumigatus (>40 colony-forming units/m(3)) were observed in the main hospital corridors, and A. fumigatus contamination was detected up to six times per year in the haematology corridors. In order to limit fungal exposure, the decision was made to perform additional checks on ventilation systems and heating, increase biocleaning and develop clear instructions.

CONCLUSION

No significant link was observed between A. fumigatus detection and invasive aspergillosis. Weekly surveys have helped to improve the vigilance of the medical teams. Nevertheless, 58 cases of invasive aspergillosis have been identified since 2007.