Occurence of infected amoebae in cooling towers compared with natural aquatic environments: Implications for emerging pathogens

    Authors

    S. G. Berk; J. H. Gunderson; A. L. Newsome; A. L. Farone; B. J. Hayes; K. S. Redding; N. Uddin; E. L. Williams; R. A. Johnson; M. Farsian; A. Reid; J. Skimmyhorn;M. B. Farone

    Comments

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    Abbreviated Journal Title

    Environ. Sci. Technol.

    Keywords

    LEGIONELLA-LIKE; MICROORGANISMS; PROTOZOA; Engineering, Environmental; Environmental Sciences

    Abstract

    Many species of bacteria pathogenic to humans, such as Legionella, are thought to have evolved in association with amoebal hosts. Several novel unculturable bacteria related to Legionella have also been found in amoebae, a few of which have been thought to be causes of nosocomial infections in humans. Because amoebae can be found in cooling towers, we wanted to know whether cooling tower environments might enhance the association between amoebae and bacterial pathogens of amoebae in order to identify potential "hot spots" for emerging human pathogens. To compare occurrence of infected amoebae in natural environments with those in cooling towers, 40 natural aquatic environments and 40 cooling tower samples were examined. Logistic regression analysis determined variables that were significant predictors of the occurrence of infected amoebae, which were found in 22 of 40 cooling tower samples but in only 3 of the 40 natural samples. An odds ratio showed that it is over 16 times more likely to encounter infected amoebae in cooling towers than in natural environments. Environmental data from cooling towers and natural habitats combined revealed dissolved organic carbon (DOC) and pH were predictors of the occurrence of the pathogens, however, when cooling tower data alone were analyzed, no variables accounted for the occurrence. Several bacteria have novel rRNA sequences, and most strains were not culturable outside of amoebae. Such pathogens of amoebae may spread to the environment via aerosols from cooling towers. Studies of emerging infectious diseases should strongly consider cooling towers as a source of amoeba-associated pathogens.

    Journal Title

    Environmental Science & Technology

    Volume

    40

    Issue/Number

    23

    Publication Date

    1-1-2006

    Document Type

    Article

    Language

    English

    First Page

    7440

    Last Page

    7444

    WOS Identifier

    WOS:000242367100054

    ISSN

    0013-936X

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