Chapter 11 : Classical and Molecular Methods To Measure Fecal Bacteria

Abstract:

This chapter provides an overview of classical and molecular methods to detect and enumerate fecal indicator bacteria (FIB). It summarizes general field sampling and laboratory considerations for using FIB methods, outlines the more common laboratory approaches to measure FIB, describes methods for certain key FIB, identifies standard methods, and summarizes some considerations for using FIB methods in particular situations or environments. The chapter is limited to providing an overview of some of the more common molecular approaches that have been used to detect FIB. Molecular methods such as Immunological methods, fluorescent in situ hybridization (FISH), PCR and quantitative PCR (qPCR) are also discussed. Although these new molecular methods are likely to remain research tools for years to come, they open up great potential for developing new FIB methods to expand the water quality assessment toolbox in the future. Advances in molecular methods offer potential to enumerate both culturable and non-culturable cells of Escherichia coli. The enterococci are a subgroup of the fecal streptococci. Growth of Pfizer selective enterococcus (PSE) isolates in brain-heart infusion broth confirms presence of enterococci. When collecting water samples, a maximum holding time of 24 hours has been proposed for enumerating Clostridium perfringens. Uncultured organisms that are genetically similar to cultured Bacteroides have gained popularity as indicator bacteria.