title: Evaluation of Techniques for Measuring Microbial Hazards in Bathing Waters: A Comparative Study.
abstract: Recreational water quality is commonly monitored by means of culture based faecal indicator organism (FIOs) assays. However, these methods are costly and time-consuming; a serious disadvantage when combined with issues such as non-specificity and user bias. New culture and molecular methods have been developed to counter these drawbacks. This study compared industry-standard IDEXX methods (Colilert and Enterolert) with three alternative approaches: 1) TECTA™ system for E. coli and enterococci; 2) US EPA's 1611 method (qPCR based enterococci enumeration); and 3) Next Generation Sequencing (NGS). Water samples (233) were collected from riverine, estuarine and marine environments over the 2014-2015 summer period and analysed by the four methods. The results demonstrated that E. coli and coliform densities, inferred by the IDEXX system, correlated strongly with the TECTA™ system. The TECTA™ system had further advantages in faster turnaround times (~12 hrs from sample receipt to result compared to 24 hrs); no staff time required for interpretation and less user bias (results are automatically calculated, compared to subjective colorimetric decisions). The US EPA Method 1611 qPCR method also showed significant correlation with the IDEXX enterococci method; but had significant disadvantages such as highly technical analysis and higher operational costs (330% of IDEXX). The NGS method demonstrated statistically significant correlations between IDEXX and the proportions of sequences belonging to FIOs, Enterobacteriaceae, and Enterococcaceae. While costs (3,000% of IDEXX) and analysis time (300% of IDEXX) were found to be significant drawbacks of NGS, rapid technological advances in this field will soon see it widely adopted.
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Monash University, Clayton, Victoria, Australia.
authors.forename: Christelle
authors.initials: C
authors.lastname: Schang
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Monash University, Clayton, Victoria, Australia.
authors.forename: Rebekah
authors.initials: R
authors.lastname: Henry
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Monash University, Clayton, Victoria, Australia.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Kolotelo
authors.affiliation: Melbourne Water, Docklands, Victoria, Australia.
authors.forename: Toby
authors.initials: T
authors.lastname: Prosser
authors.affiliation: Melbourne Water, Docklands, Victoria, Australia.
authors.forename: Nick
authors.initials: N
authors.lastname: Crosbie
authors.affiliation: Melbourne Water, Docklands, Victoria, Australia.
authors.forename: Trish
authors.initials: T
authors.lastname: Grant
authors.affiliation: Environment Protection Authority Victoria, Melbourne, Victoria, Australia.
authors.forename: Darren
authors.initials: D
authors.lastname: Cottam
authors.affiliation: Mornington Peninsula Shire, Rosebud, Victoria, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: O'Brien
authors.affiliation: Micromon, Monash University, Clayton, Victoria, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Coutts
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Monash University, Clayton, Victoria, Australia.
authors.forename: Ana
authors.initials: A
authors.lastname: Deletic
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Monash University, Clayton, Victoria, Australia.
authors.forename: David T
authors.initials: DT
authors.lastname: McCarthy
mesh_terms: D058491:Bacterial Load; D001431:Bacteriological Techniques / Q000191:economics / Q000379:methods*; D016983:Enterococcus / Q000235:genetics / Q000302:isolation & purification; D004784:Environmental Monitoring / Q000379:methods*; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification; D005618:Fresh Water / Q000382:microbiology*; D059014:High-Throughput Nucleotide Sequencing; D012680:Sensitivity and Specificity