Phenotypic variations of enterococci in surface waters: analysis of biochemical fingerprinting data from multi-catchments.
OBJECTIVE
The aim of this study was to identify the prevalence of environmentally adapted enterococci strains by analysing biochemical fingerprinting (BF) data of 3952 enterococci isolates collected over 5 years from the six catchments in Southeast Queensland, Australia.


RESULTS
A BF method was used to type 3952 enterococci isolates from six catchments. The environmental isolates were compared with a large existing BF library comprised of 5803 enterococci isolates from 10 host groups. Environmental isolates belonged to 801 biochemical phenotypes (BPTs), of which, an average of 29.2% was specific to each catchment. When compared with the BF library, an average of 79.5% BPTs from each catchment was identical to those in the library (i.e. host-origin BPTs). The remaining 20.5% was regarded as non-host origin BPTs, as they were not in the library and constituted only 5.3% of the total isolates tested for each catchment.


CONCLUSIONS
Our data suggest that less than 5% of studied environmental strains was not identical to those in the library and seemed to be of environmental origin. From a microbial source tracking context, such low level of environmentally adapted strains can have a minimal impact on the performance of the library-based methods if a large number of isolates were tested from both the host groups and environmental waters.


CONCLUSIONS
These data shed light on the importance of the size and representativeness of library-based source-tracking methods and their implications for the identification of faecal pollution in environmental waters.
Ahmed
W
W
Department of Natural Resources and Water, Brisbane, Queensland, Australia. Warish.Ahmed@nrw.qld.gov.au
Katouli
M
M
D000222:Adaptation, Physiological; D000818:Animals; D016172:DNA Fingerprinting / Q000379:methods; D001330:Electronic Data Processing; D016983:Enterococcus / Q000235:genetics* / Q000302:isolation & purification; D004784:Environmental Monitoring / Q000379:methods*; D005243:Feces / Q000382:microbiology; D015723:Gene Library; D005843:Geography; D006801:Humans; D010641:Phenotype; D011793:Queensland; D014871:Water Microbiology