Evaluation of the methods for enumerating coliform bacteria from water samples using precise reference standards

Abstract

Aims: To use BioBallTM cultures as a precise reference standard to evaluate methods for enumeration of Escherichia coli and other coliform bacteria in water samples. Methods and Results: Eight methods were evaluated including membrane filtration, standard plate count (pour and spread plate methods), defined substrate technology methods (ColilertTM and ColisureTM), the most probable number method and the Petrifilm disposable plate method. Escherichia coli and Enterobacter aerogenes BioBallTM cultures containing 30 organisms each were used. All tests were performed using 10 replicates. The mean recovery of both bacteria varied with the different methods employed. Conclusions: The best and most consistent results were obtained with Petrifilm and the pour plate method. Other methods either yielded a low recovery or showed significantly high variability between replicates. Significance and Impact of the Study: The BioBallTM is a very suitable quality control tool for evaluating the efficiency of methods for bacterial enumeration in water samples.

ColiSense, today's sample today: A rapid on-site detection of β-d-Glucuronidase activity in surface water as a surrogate for E. coli

“…These figures agree with the work of Lebaron who in a much more extensive study using the discontinuous 4-MUG method for measuring GUS activity reported CVs less than 15% [25]. By comparison, culture based MPN methods typically report CVs of 15% to 30% [32]. …”

Investigation of an outbreak of Salmonella Typhi in Battalgazi district, Malatya-Turkey

“…from time to time (6,10,21). Upon its isolation from blood (7 isolates) and stool samples (3 isolates) of 10 individuals within two days at the Clinical Microbiology laboratory, an outbreak investigation study was performed including molecular epidemiological studies by AP-PCR method.…”

A combination of PhP typing and β-d-glucuronidase gene sequence variation analysis for differentiation of Escherichia coli from humans and animals

“…Various human enteric pathogens, such as Salmonella spp., Cryptosporidium, Hepatitis A, Norwalk virus, and enteroviruses, have been found in surface waters (Lipp et al 2001;Griffin et al 2003;Wohlsen et al 2006;Ahmed et al 2009), and incidents of outbreaks are often recorded (Craun et al 2006;Arveloa et al 2012). However, it is not technically or economically feasible for water management agencies to screen for all waterborne pathogens.…”