ABSTRACT
Cave tourism represents the main threat for caves and for their conservation. Visitors cause important changes in the microclimate and introduce organic carbon and microorganisms into caves. The visitors leave behind skin cells, hair, soil trapped on shoe soles and occasionally vomit, faeces and urine. Recently we faced a new human impact on show caves: chewing gum stuck to the walls. We have found chewing gum on the walls of Cueva del Tesoro, Rincón de la Victoria, Málaga, Spain. The bacteria colonising the chewing gum were represented by members of Actinobacteria, Alphaproteobacteria and Firmicutes while the fungi were members of the Ascomycota, order Eurotiales and Hypocreales. From the bacteria, the isolation of Brachybacterium fresconis, Microbacterium aerolatum, Sphingopyxis italica and Bacillus litoralis were noteworthy as were the presence of Aspergillus, Fusarium and Penicillium species from the fungi.
