No abstract

Waterborne diseases are a serious threat because of their ability to infect a high number of individuals in a short time span, such as during outbreaks of Legionellosis. This significantly highlights the need for the rapid detection and quantification of bacteria in environmental water samples. The aim of this study was to investigate the feasibility of quantitative Polymerase Chain Reaction (qPCR) for the detection of Legionellapneumophila (L. pneumophila) in environmental water samples and comparison of standard culture methods for Legionella detection with qPCR. Our study reached a negative predictive value (NPV) for L. pneumophila of 80.7% and for L. pneumophila serogroup 1 (sg1) the calculated NPV was 87.0%. The positive predictive value (PPV) for L. pneumophila was 53.9% and for L. pneumophila sg1 PPV was 21.4%. Results showed a correlation between qPCR and culture with an R2 value of 0.8973 for L. pneumophila, whereas no correlation was observed for the detection of L. pneumophila sg1. In our study, qPCR proved useful for the identification of L. pneumophila negative samples. However, despite the obvious benefits (sample handling, rapid generation of results), qPCR needs to be improved regarding the PPV before it can replace culture in water quality assessment.

In the present study the spectrum and the incidence of fungi in potting soils and compost was investigated. Since soil is one of the most important biotopes for fungi, relatively high concentrations of fungal propagules are to be expected. For detection of fungi, samples of commercial soils, compost and soils from potted plants (both surface and sub-surface) were suspended and plated onto several mycological media. The resulting colonies were evaluated qualitatively and quantitatively. The results from the different sampling series vary, but concentrations on the surface of potted plants and in commercial soils are increased tenfold compared to compost and sub-surface soils. Median values range from 9.5 × 10(4) colony forming units (CFU)/g to 5.5 × 10(5) CFU/g. The spectrum of fungi also varies in the soils. However, all sampling series show high proportion of Aspergillus and Penicillium species, including potentially pathogenic species such as Aspergillus fumigatus. Cladosporium, a genus dominant in the ambient air, was found preferably in samples which were in contact with the air. The results show that potentially pathogenic fungi are present in soils. Immunocompromised individuals should avoid handling soils or potted plants in their immediate vicinity.