accounted for by being PCR positive for either P. chrysogenum
or P. rubens.
Based on rapid discrimination the 430 Penicillium isolates
recovered by air sampling and tested by PCR from conidia, 58
(13.5 %) isolates were found to be P. chrysogenum and 65
(15.1 %) isolates P. rubens. There was no overlapping of positive
results, adding further evidence that these primers are
species-specific. Of the 430 isolates, a sub-sample of 148 were
tested for P. chainii and P. floreyi, however, no positives were
detected confirming the rarity of these two species. The
locations sampled were grouped into five similar environments;
the varied populations of P. chrysogenum and P. rubens
are displayed in Table 2.
No significant difference ( p > 0.05) was found between the
numbers of P. chrysogenum and P. rubens detected in MEA and
DG18 samples taken at the same location: Bakerloo Line
( p ¼ 0.529), St Mary’s Hospital ( p ¼ 0.389) and the Outdoors
( p ¼ 0.308), nor between 500 and 1 000 l of air sample volume
( p ¼ 0.071). This allowed the data set to be statistically analysed
together to compare sample environments.
ANOVA revealed no significant difference in the distribution
of P. chrysogenum between locations ( p ¼ 0.173) but
did for P. rubens ( p ¼ 0.002). Post-hoc analysis by the
TukeyeKramer test revealed significant difference was located.
There was a statistical difference ( p < 0.05) in the number
of P. rubens between the Central and Bakerloo Lines, and
between the Central Line and the Outdoors.