Specificity for field enumeration of Escherichia coli in tropical surface waters

In remote rural areas in developing countries, bacteriological monitoring o ften depends on the use of commercial field media. This paper evaluates a c ommercial field medium used for the enumeration of Escherichia coli in diff erent surface waters under primitive field conditions in rural Pakistan. in order to verify the field kit, 117 presumptive E. coli isolates have been tested, finding a specificity of only 40%. Bai excluding some strains based on colony colours, the calculated specificity could he increased to 65%. T hus, it is suggested that prior to use in a tropical environment, the speci ficity of any commercial medium used should be tested with representative t ropical isolates, in order to increase the specificity. (C) 2001 Elsevier S cience B.V, Arl rights reserved.