Identification of Fungal Species
Once the air or surface mould samples are collected they need to be analysed. Whether the samples are taken to a commercial laboratory or an environmental consultant either way they should be analysed by experienced individuals. Features that characterise good laboratories include the following:
- At least one year of experience with the type of sample they analyse (so make sure the Microbiology Lab actually deals with fungi and not only with bacteria). Get the name of the person who performs the identification and check their credentials. A PhD or other formal education says nothing about where and how a person learnt to identify fungi. It is better to look if there was any special training in mycology undertaken.
- The Lab / Consultant should have quality control data on hand and a written quality insurance plan. Furthermore the voluntary participation of a mycological round robin test should be performed, and participation in at least one recognised certification process is essential.
- There should be sufficient client support for all questions, including the explanation of the analytical interpretation and results.
It needs to be pointed out that no matter how good a mycologist says he is nobody is able to identify all fungi out there. It’s impossible, that way you need to know where to get a little help. For example large genera like Penicillium can take a lifetime to master, and there are currently only one or two people on the planet that is capable of identifying all of them. When we are presented with a new or difficult fungal identification we have a number of options.
First we use our skills to identify the fungi down to his genera and then down to a couple of species possible in this genera. Following that we can have a type of DNA analysis performed (PCR) or we can send samples to reference laboratories in Europe and request expert analysis from a specialist on those particular genera. Genera and species are like the first and second name for a fungus. For a correct risk assessment it is essential to get both names right.
For example Penicillium roqueforti is used for cheese production, while Penicillium fumigatus is causing severe lung infections in immuno-suppressed patients in hospitals. Knowing what you are dealing with always keeps you one step ahead of the fungal contamination. Some fungi produce masses of spores which easy become airborne, while others only have a few sticky spores hardly ever found in the air (never the less toxic).
The job in front of an environmental mycologist can be truly daunting, considering the thousands of species that are known. Fortunately however, there is a smaller range of species that occur more commonly indoors. This brings down the list of species that a mycologist needs to know to some several thousand. However this still requires considerable training and experience. Be aware of the unfortunate thing that is happening in our industry. Any body with some basic knowledge and some off the shelf equipment can go out, capture fungi and provide seemingly meaningful concentrations of airborne fungi. Some might even be able to crudely identify the fungi to fit into one of the several genera. However, very few are really able to identify fungi correctly.
Tests in the US have shown that about 40% of fungal identification is completely wrong. Our own experience here in Australia is that very often the wrong sampling techniques and agar media are used. Some of the well known laboratories have little or no identification literature (no you can’t identify fungi by there colony colour from a picture CD). A lack of education and experience in this field lead to a lot of miss identification in the absence of Government Guidelines. Lets hope that the urgent need for investigators to determine the extend and mechanisms of health effects caused by fungi let this industry mature quickly.