Outdoor airborne fungi: sampling strategies

Summary A six-stage Andersens's sampler was compared with a single stage type (SAS) for the collection of airborne fungi particles. The efficiency of two non selective culture media, and namely malt agar (MA) and potato dextrose agar (PDA), which were both modified in order to inhibit bacterial growth, was compared as well. An overall assessment of quantitative results suggests that the two samplers have a comparable degree of efficiency. However, the SAS appears to collect a greater number of CFU/m³ in absence of wind and viceversa the Andersen one appears to be more efficient in the presence of wind. The number of species detected with the SAS device is smaller, thus requiring an increased number of suctions. Andersen sampler sieving, according to the aerodynamic characteristics of the particles, appears to be not too accurate: there is an overlap from stage to stage of the sampler and some larger particles settle on smaller particle-collecting stages and viceversa. The PDA, with streptomycin and chloramphenicol, is better and closer to the natural distribution pattern: the number of CFU/m³ is higher although the number of the collected species is about the same.