The virus SARS-CoV-2, which has caused the recent COVID-19 pandemic, may be present in the stools of COVID-19 patients. Therefore, we aimed to detect SARS-CoV-2 in wastewater for surveillance of SARS-CoV-2 in the population. Samples of untreated wastewater were collected from 33 wastewater treatment plants (WWTPs) of different sizes within the Czech Republic. SARS-CoV-2 RNA was concentrated from wastewater and viral RNA was determined using real-time reverse transcription polymerase chain reaction (RT-qPCR). SARS-CoV-2 RNA was detected in 11.6% of samples and more than 27.3% of WWTPs; in some of them, SARS-CoV-2 was detected repeatedly. Our preliminary results indicate that an epidemiology approach that focuses on the determination of SARS-CoV-2 in wastewater could be suitable for SARS-CoV-2 surveillance in the population.

Aims:  To develop a PCR‐based method for reliable detection of Escherichia coli that enables its differentiation from biochemically and phylogenetically related bacteria. Methods and Results:  Using multiplex PCR targeting four genes (cytochrome bd complex, lactose permease, β‐d‐glucuronidase, and β‐d‐galactosidase) the possibility of specific detection of various control E. coli strains was tested. It was found that four PCR fragments of the predicted size were observed only for E. coli strains, but not for relatives as close as Shigella sp. or other enterobacteria. Not surprisingly, this method enabled us to identify also E. coli strains which did not exhibit the β‐d‐glucuronidase activity. Our multiplex PCR was also successfully used for identification of 95 environmental isolates of E. coli. Conclusions:  The developed PCR‐based method, in which four genes coding for lactose permease, cytochrome bd complex, β‐d‐glucuronidase, and β‐d‐galactosidase, serve as target DNA sequences, allows precise and reliable detection of E. coli strains. Significance and Impact of the study:  The suggested approach increases the specificity of detection of E. coli since it enables to distinguish E. coli from Shigella sp. and other relative enterobacteria.

Wastewater treatment plants (WWTPs) primarily serve to protect the environment. Their task is to clean waste water from the agglomerations. On the other hand wastewater treatment plants can also negatively affect the environment in their neighbourhood. These include emissions of odour and microorganisms. This article discusses the microbial contamination of the air, called bioaerosols in selected wastewater treatment plant for 18 000 p.e. From results of the work is evident that the largest group of microorganisms in the monitored air were psychrophilic and mesophilic bacteria and microscopic fungi. The number of psychrophilic bacteria ranged from 14 to 12 000 CFU/m3 (colony forming units in 1 m3), the number of mesophilic bacteria varied in the range from 20 to 18 500 CFU/m3 and the fungi from 25 to 32 000 CFU/m3 in the air. The amount of actinomycetes ranged from 1 to 1 030 CFU/m3 and faecal coliform bacteria from 0 to 2 500 CFU/m3. Furthermore, it was confirmed that the highest air contamination was around the activation tank, area for dewatered sludge and around the building of mechanical cleaning, depending on the season. The density of studied microorganisms correlated with air temperature.

The presence of enteric pathogens in water resources represents a serious risk for public health. Therefore, their precise detection, and especially detection of E. coli, which is obviously regarded as the main indicator of faecal contamination of water, is an essential step in ensuring bacterial safety of water. Numerous PCR protocols for detection of E. coli have been published to date. They are usually based on amplification of regions derived from lacZ (beta-D-galactosidase) and uidA (beta-D-glucuronidase) gene sequences. However, these methods are not universal enough for precise detection of all E. coli strains found in water samples. We developed a novel triplex PCR method for detection of E. coli in which cyd gene coding for cytochrome bd complex was co-amplified along with lacZ and uidA genes. Our triplex PCR approach significantly increases the specificity and reliability of E. coli detection in water samples. This approach allowed us to distinguish Shigella flexneri from E. coli. In addition, we were able to detect even non-coliform Klebsiella and Raoutella spp., some of which can also cause infections to humans.

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