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The presence and level of faecal indicator bacteria are important factors in estimating the microbiological quality of surface water and the risk of human infection upon exposure to this water. Until 2014, ISO 9308-1:2000 was available and used to enumerate faecal indicator Escherichia coli in bathing water. In 2014, this ISO was technically revised and replaced by ISO 9308-1:2014. This ISO introduced a less selective method for enumeration of E. coli that allows non-specific growth from waters containing high levels of bacteria, such as surface waters. This implies that currently there is no suitable reference membrane filtration method for the compliance monitoring of official bathing sites for E. coli according to the European Bathing Water Directive. Here, the performance characteristics of three chromogenic culture media, namely Tryptone Bile X-glucuronide (TBX) agar, Chromogenic Coliform Agar (CCA), and CHROMagar E. coli/Coliform (ECC) were investigated at 44 °C for water with varying levels of bacteria according to ISO 13843:2017. Based on performance characteristics, colony counts, and practical usage, TBX appeared the most suitable culture medium for the enumeration of E. coli in bathing water and other waters with high levels of background bacteria, such as surface water in agricultural areas and wastewater discharge points. HIGHLIGHTS Performance characteristics at 44 °C, after resuscitation at 36 °C, were comparable for the tested chromogenic culture media TBX, CCA, and ECC.; Based on performance characteristics, colony counts, and practical usage, TBX was selected as the preferential culture medium.;

This paper analyses the results of microbiological analyses of bathing water at the Kravica Waterfall during 2018 and 2019 and the impact of bathers on bathing water quality. The microbiological analysis of the samples was performed by the Federal Institute of Public Health in Mostar in accordance with the regulations of Directive 2006/7 EC for management of quality of bathing water. Faecal streptococci were determined using the membrane filtration method BAS EN ISO 7899-2:2003. Escherichia coli was determined using the membrane filtration method for waters with low bacterial background flora BAS EN ISO 9308-1:2015. The quality of bathing water is assessed on the basis of parameters determined by the current Directive 2006/7/EC. The number of visitors does not have a significant impact on the quality of bathing water; the reason is that of the total number of visitors there is a small percentage of bathers. During the bathing seasons in 2018 and 2019, the bathing water at the Kravica Waterfall was of excellent quality.

Background microorganism growth on Chromogenic Coliform Agar (CCA) can be challenging. For this reason, a new alternative method with a Cefsulodin/Vancomycin (CV)-supplemented CCA should be developed in this study. CCA supplemented with CV was validated according to ÖNORM EN ISO 16140-4:2021 using water from natural sources in Styria, Austria. Results show that the alternative method using the supplemented CCA has similar values in relation to sensitivity (82.2%), specificity (98.6%) and higher selectivity (59%) compared to the reference method. Repeatability and reproducibility were acceptable for the alternative method and showed similar results with the reference method. The alternative method shows a very low false positive rate and a low false negative rate paired with good performance regarding the inclusion study. The exclusion study shows the advantage of our method by suppressing background microorganisms and facilitating the process of enumeration of Escherichia coli and other coliform bacteria on CCA plates. Aeromonas hydrophila and Pseudomonas aeruginosa growth was inhibited using the supplement. To conclude, the coliform CV selective supplement combined with CCA is an appropriate tool for coliform bacteria detection in water samples.

Vibrio cholerae belonging to serogroups other than O1 and O139 are opportunistic pathogens which cause infections with a variety of clinical symptoms. Due to the increasing number of V. cholerae non-O1/non-O139 infections in association with recreational waters in the past two decades, they have received increasing attention in recent literature and by public health authorities. Since the treatment of choice is the administration of antibiotics, we investigated the distribution of antimicrobial resistance properties in a V. cholerae non-O1/non-O139 population in a large Austrian lake intensively used for recreation and in epidemiologically linked clinical isolates. In total, 82 environmental isolates - selected on the basis of comprehensive phylogenetic information - and nine clinical isolates were analyzed for their phenotypic antimicrobial susceptibility. The genomes of 46 environmental and eight clinical strains were screened for known genetic antimicrobial resistance traits in CARD and ResFinder databases. In general, antimicrobial susceptibility of the investigated V. cholerae population was high. The environmental strains were susceptible against most of the 16 tested antibiotics, except sulfonamides (97.5% resistant strains), streptomycin (39% resistant) and ampicillin (20.7% resistant). Clinical isolates partly showed additional resistance to amoxicillin-clavulanic acid. Genome analysis showed that crp, a regulator of multidrug efflux genes, and the bicyclomycin/multidrug efflux system of V. cholerae were present in all isolates. Nine isolates additionally carried variants of blaCARB–7 and blaCARB–9, determinants of beta-lactam resistance and six isolates carried catB9, a determinant of phenicol resistance. Three isolates had both blaCARB–7 and catB9. In 27 isolates, five out of six subfamilies of the MATE-family were present. For all isolates no genes conferring resistance to aminoglycosides, macrolides and sulfonamides were detected. The apparent lack of either known antimicrobial resistance traits or mobile genetic elements indicates that in cholera non-epidemic regions of the world, V. cholerae non-O1/non-O139 play a minor role as a reservoir of resistance in the environment. The discrepancies between the phenotypic and genome-based antimicrobial resistance assessment show that for V. cholerae non-O1/non-O139, resistance databases are currently inappropriate for an assessment of antimicrobial resistance. Continuous collection of both data over time may solve such discrepancies between genotype and phenotype in the future.

In early autumn 2011, three dogs died after they had been exposed to a Microcystis aeruginosa bloom on Lake Amstelmeer, The Netherlands. The cyanobacterial scum from the lake contained up to 5.27 × 103 μg g−1 dry-weight microcystin, the vomit of one of the dogs contained on average 94 µg microcystin g−1 dry-weight. In both cases, microcystin-LR was the most abundant variant. This is the first report of dog deaths associated with a Microcystis bloom and microcystin poisoning in The Netherlands.

An electrolysed solution of sodium chloride was examined for its disinfection potential in drinking and bathing water. The electrolysis of NaCl ((=1%) in tap water was performed at room temperature using a 10 A electric current in an electrolysis apparatus. Some laboratory tests were made, initially to determine the stability and efficiency of the disinfectant. Chemical and microbiological measurements of the treated water (according to DIN 19643 for bathing water) were then carried out before and after addition of the disinfectant agent.

In order to determine the hygiene indices of bathing water, and it's water quality, a survey and laboratory analysis was recently undertaken on 34 outdoor public swimming pools out of a total 126 in Tehran metropolitan area according to simple random sampling without replacement. This survey revealed remarkable evidence of waver bacterial contamination at heavy bather load time. Examined water samples from pools failed to show the presence of any common enteric viruses, but bacteria especially Pseudeomonas aeruginosa, Staphylococcus aureus and E.coli were isolated from 76, 21 and 35 percent of samples respectively. Bacterial indices of 1100 Faecal Coliform by MPN were detected in 21 percent out of cases, results were obtained when the residual chlorine content of the pool ranged from 0.05 to Zero ppm. 21 percent out of the total public swimming pools under the study do not use any disinfecting agents and nine pools did not use any treatment. Chemical analyses of swimming pools indicated obvious degree of pollution, for instance residual chlorine level ranged from zero to 0.6 ppm while Ammonia Nitrogen ranged from 0.12 to 1.32 ppm as N and chloride ranged from 25 to 430 ppm as Cl- .