WaterSubject

Whenrecreational waters are contaminated with pathogenic microorganisms, itis important for public health officials to determine the source of thecontamination to remedy the problem and prevent bather exposure topathogenic microorganisms. Bacterial source tracking BST is oftenused to determine the source of fecal contamination in recreationalwaters. Several phenotypic e.g. antibiotic sensitivity testing andgenotypic e.g. ribotyping, repetitive sequence PCR, s rDNA analysis,pulse-field gel electrophoresis methods have been used as BST tools .While many of these methods show promise, most are complex, costly, andoften require days to complete. Reducing the time required for many ofthese BST tools is of particular importance, because the longer ittakes to determine the source of fecal contamination, the greater riskthere is for human exposure to pathogens present in contaminated water. identified an inability of several existing BST tools to assign unknown isolates of the indicator organism Escherichia colito their respective sources. When unknown isolates were classified bysources, five out of seven antibiotic resistance patterning,ribotyping using the EcoR restriction enzyme, pulse-field gelelectrophoresis, BOX-PCR, and REP-PCR BST tools met the minimumexpectations for correct classification, with average correct sourceassignments ranging from % to %. Such low accuracy levels wereattributed to possible variation in data collection and analysis,variability in isolates collected at different times, sharing of E. colisubtypes between different sources, and fingerprint library size. Eachof these problems can be associated with many of the BST toolscurrently used.Given the time-intensive and often ineffectivenature of many existing BST tools, the development of more rapid andaccurate methods of characterizing sources of bacterial contaminationof recreational waters is warranted. One method that shows promiseinvolves characterizing bacteria using mass spectrometry, particularlymatrix-assisted laser d@
?