Microfungi in Drinking Water: The Role of the Frog Litoria caerulea

Abstract

Microfungi were recovered from all parts of a municipal water distribution system in sub-tropical Australia even though virtually no colony-forming units were recovered from the treated water as it left the treatment plant. A study was then undertaken to determine the potential sources of the microfungal population in the distribution system. Observation of frogs (Litoria caerulea) using the internal infrastructure of a reservoir as diurnal sleeping places, together with observation of visible microfungal growth on their faecal pellets, led to an investigation of the possible involvement of this animal. Old faecal pellets were collected and sporulating fungal colonies growing on their surfaces were identified. Fresh faecal pellets were collected and analysed for microfungal content, and skin swabs were analysed for yeasts. It was found that the faeces and skin of L. caerulea carried large numbers of yeasts as well as spores of various filamentous fungal genera. While there are many possible sources of microfungal contamination of municipal drinking water supplies, this study has revealed that the Australian green tree frog L. caerulea is one of the important sources of filamentous microfungi and yeasts in water storage reservoirs in sub-tropical Australia where the animal is endemic.

Three Potential Sources of Microfungi in a Treated Municipal Water Supply System in Sub-Tropical Australia

“…Whether or not such spores can be categorised as biofilm microfungi is open to question. These probably originated as airborne spores, as discussed above, or as spores introduced into the reservoir by the frog Litoria caerulea [ 28 ]. The presence of bacterial aggregations on the coupons in the absence of fungal growth may simply represent the primary component of a very slowly developing microbial biofilm, the rate of development no doubt being controlled by the oligotrophic nature of the treated drinking water.…”

“…Formation of the microfungal component of developing biofilm on artificial coupons immersed in the oligotrophic water of storage reservoirs was also assessed. We have already established that, in areas where it is endemic, the large Australian green tree frog Litoria caerulea introduces yeasts and filamentous microfungi as well as the bacterium Escherichia coli into water storage reservoirs [ 28 , 29 ]. Whether or not some microfungal spores pass through the treatment plant, or survive the water treatment processes in a damaged state but are subsequently capable of recovering within the distribution system, is being separately investigated.…”

Forage as a Primary Source of Mycotoxins in Animal Diets

“…The issue of moulds is very topical, namely in connexion with forages from grass stands used at the end of the growing season. There are considerable differences amongst the species [ 8 , 9 ]. Mould-resistance species include Festuca arundinacea and its hybrids [ 10 ].…”

Tracking the amphibian pathogensBatrachochytrium dendrobatidisandBatrachochytrium salamandrivoransusing a highly specific monoclonal antibody and lateral‐flow technology

“…Trichosporon spp. are basidiomycete yeast-like fungi that are found in a diverse range of habitats, including soil, rivers and lakes (Colombo et al, 2011), with limited evidence for their association with the skin of frogs (Mok and Morato de Carvalho, 1985;Sammon et al, 2010). While 5C4 was reactive with H. polyrhiza in both the ELISA and LFA formats, cross-reactivity of 5C4 was not found with Chytridium and Trichosporon spp.…”