BIOCHEMICAL FINGERPRINTING OF COLIFORM BACTERIAL-POPULATIONS - COMPARISONS BETWEEN POLLUTED RIVER WATER AND FACTORY EFFLUENTS

Bacteria from different pollution sources may consist of essentially t he same species but with different strains predominating. Therefore, s ub-typing of bacterial strains recovered in the polluted water and com parison with those present in possible pollution sources is a valuable tool for identification of the source. Since such studies require inv estigations of large numbers of isolates, simple laboratory methods co mbined with automated data evaluation and presentation are necessary. The Phene Plate (PhP) system for biochemical fingerprinting of bacteri a is based on measurements of the kinetics of biochemical tests, perfo rmed in micro-plates. The system also includes mathematical models to calculate the diversity (Di) of the bacterial flora within samples, as well as the similarities between bacterial populations in different s amples as the population similarity coefficient (Sp). We have used the PhP system to type coliform bacteria isolated from a polluted river i n Sweden and from the outlets from three paper mills that were suspect ed contamination sources. From each of 27 river water samples and 8 sa mples from factory outlets, collected on eight sampling occasions, bet ween 10 and 50 coliforms were typed, yielding altogether 1,027 isolate s. The diversity among the bacteria in river water samples was general ly high (mean Di = 0.95) compared with factory outlets (mean Di = 0.63 ) which usually were dominated by isolates belonging to a few PhP type s. These PhP types were very rarely recovered from the river water sam ples which is also reflected in low similarities between bacterial pop ulations in river water and factory outlets (mean Sp = 0.03). Thus the bacteria from factory outlets did not seem to have spread downstream. In contrast, bacterial populations from sampling sites close to each other in the river were more similar to each other (mean Sp 0.13), ind icating the presence of several, diffuse contamination sources, possib ly from animal or human faecal material. (C) 1997 IAWQ. Published by E lsevier Science Ltd.