## 1 Introduction  
The 'One Health' approach recommended by WHO recognizes the inseparable link between human, animal and environmental health [1]. The most under investigated part of One Health is the environment. A seaside represents a unique ecological system that is highly influenced by industrial development and discharge of wastewater. Fecal contamination of seawater is characterized by an increase in concentration of _Escherichia coli_ and intestinal enterococci. These bacteria are common members of gut microbiome in mammals and birds but are also opportunistic pathogens for human and animals [2]. _E. coli_ and enterococci are used as standard for waterborne pathogens and as fecal indicator bacteria in water quality testing all over the world because these bacteria are easily culturable (EU BDW 2006/7/EC). The regular monitoring of _E. coli_ content in water enables to avoid health risks, especially from exposure in the foreseeable context of short-term pollution on unusual circumstances. In addition, marine recreational waters were shown to be potential source of resistant bacteria because they may contribute to the dissemination of microorganisms carrying antimicrobial resistance genes [3]. To monitor and control microbiological quality of bathing and recreational seawater, the common routine practice is regular water sampling and analysis for _E. coli_ levels on a weekly or monthly basis. European directive 2006/7/EC concerning the management of bathing water quality refers as \"excellent quality\" coastal water with less than 250 CFU of _E. coli_ in 100 mL, and as a \"good quality\" water _E. coli_ levels between 250 and 500 CFU/100 mL based upon a 95 th-percentile of microbiological values. The number of _E. coli_ colonies should not exceed 500 CFU/100 mL upon a 90 th percentile of microbiological values to be considered as \"sufficient\". The assessment of the potential risk is dependent on detection methods that quantify bacterial indicator concentrations. The reference methods of analysis are membrane filtration methods, ISO 9308-3 or ISO 9308-1, that enable to concentrate large amount of water samples (minimum capacity is typically 250 mL) before bacteria enumeration. Official detection methods are sensitive and accurate but time consuming as they are based on bacterial culture on agar plates and colony counting. The results take 2-3 days, which does not meet the demand of rapid seawater testing because an outdated information is forwarded to the public in some cases. Rapid test ISO 9308-1:2000 is faster than the reference tests, since it provides results within 24 h. The rapid test includes 4-5 h resuscitation period after water filtration to enhance the recovery of viable bacteria, and bacterial enumeration after culturing. The specificity of the test can be compromised by background bacterial flora that can be also concentrated by the filtration and then grow on the non-selective agar plates. Another limitation of the official and rapid methods is that in seawater under multi-stress situation, bacteria may enter 'viable but nonculturable' (VBNC) status. Although VBNC bacterial cells do not divide and, thus, do not form colonies on nutritional agars that normally support their growth, they were shown to be metabolically active in seawater retaining their pathogenicity [4]. Using this survival strategy, _E. coli_ may rest undetected in seawater by routinely used methods but resuscitate and cause infections. The public expects to receive adequate and timely information on results of microbiological quality of bathing water. For this, an efficient and accurate control system of bathing water is one of the priorities of coastal touristic area. In some cases, noncompliance to water quality standard would not come to a regulatory agency's attention until the next scheduled monitoring. When monitoring is infrequent, it is often not known whether the noncompliance is due to a pollution incident that has occurred shortly prior to the monitoring or an incident that has occurred days or weeks before [5].