Environmental spreading of clinically relevant carbapenem-resistant gram-negative bacilli: the occurrence of blaKPC-or-NDM strains relates to local hospital activities

Background Aquatic matrices impacted by sewage may shelter carbapenem-resistant (CR) Gram-negative bacilli (GNB) harboring resistance genes of public health concern. In this study, sewage treatment plants (STPs) servicing well-defined catchment areas were surveyed for the presence of CR-GNB bearing carbapenemase genes (blaKPC or blaNDM). Results A total of 325 CR-GNB were recovered from raw (RS) and treated (TS) sewage samples as well as from water body spots upstream (UW) and downstream (DW) from STPs. Klebsiella-Enterobacter (KE) group amounted to 116 isolates (35.7%). CR-KE isolates were recovered from TS, DW (35.7%) and RS samples (44.2%) (p = 0.001); but not from UW samples. KE isolates represented 65.8% of all blaKPC or blaNDM positive strains. The frequency of blaKPC-or-NDM strains was positively associated with the occurrence of district hospitals located near STPs, as well as with the number of hospitalizations and of sewer connections serviced by the STPs. blaKPC-or-NDM strains were recovered from ST samples in 7 out of 14 STPs, including four tertiary-level STPs; and from 6 out of 13 DW spots whose RS samples also had blaKPC-or-NDM strains. Conclusions Clinically relevant GNB bearing blaKPC-or-NDM resist sewage treatments and spread into environmental aquatic matrices mainly from STPs impacted by hospital activities.

Sanitary sewage

The treatment and disposal of domestic sewage is one of Brazil's main challenges. Sewage composition varies with the habits of the population and the frequency with which new contaminants are released into the environment. This study is a bibliographical review of the main aspects related to the characterization and composition of sanitary sewage, types of sewage treatment systems and pertinent legislation; and toxicity of domestic effluents. The review was based on publications available on Science Direct, Google Scholar and Scielo, as well as on printed publications, relevant legislation, and normative instructions. The research period adopted for the selection of publications was from 2005 to 2021. We found out that, in addition to the levels of organic matter from domestic sewage, residues from products used in daily life, such as pharmaceuticals and cleaning products, can be found in effluents in concentrations harmful to the environment. Often, the types of treatment used in municipal sewage treatment plants do not efficiently remove these contaminants. Thus, even if sewage is treated to meet the limits required for the physical-chemical and biological parameters established by law, domestic effluent can present a high potential for toxicity to various aquatic species such as microcrustaceans, mollusks and fish. Thus, ecotoxicological analyses represent a remarkable mechanism for indicating the efficiency of removal of emerging contaminants present in treated sanitary effluent, in addition to indicating the deleterious effects caused by these residues to the environment and ecosystems associated with the receiving water body.

ANALYSIS OF THE FEATURES OF CREATING A UNIFIED SCHEME FOR THE RECONSTRUCTION OF SEWAGE TREATMENT PLANTS OF THE REPUBLIC OF CRIMEA

The article deals with the problem of construction and reconstruction of sewage treatment plants and the creation of a new unified scheme for the reconstruction of sewage treatment plants of the Republic of Crimea to bring the parameters of wastewater treatment to the norms of Russian legislation.

Surveillance of SARS-CoV-2 in Sewage Treatment Plants between January 2020 and July 2021 in Taiwan

An outbreak of a new type of coronavirus pneumonia (COVID-19) began in Wuhan, Hubei Province, China, at the end of 2019, and it later spread to other areas of China and around the world. Taiwan reported the first confirmed case from an individual who returned from Wuhan, China, in January 2020 for Chinese New Year. Monitoring microbes in environmental sewage is an important epidemiological indicator, especially for pathogens that can be shed in feces such as poliovirus. We have conducted additional SARS-CoV-2 sewage testing since January 2020 using a well-established poliovirus environmental sewage surveillance system in Taiwan. Wastewater samples were collected from 11 sewage treatment plants from different parts of Taiwan twice a month for laboratory testing. By the end of July 2021, 397 wastewater specimens had been tested, and two samples were positive for SARS-CoV-2. These two wastewater samples were collected in the northern region of Taiwan from Taipei (site A) and New Taipei City (site C) at the beginning of June 2021. This result is consistent with the significant increase in confirmed COVID-19 cases observed in the same period of time. As the pandemic ebbed after June, the wastewater samples in these areas also tested negative for SARS-CoV-2 in July 2021.

Study on the Characteristics of Antibiotic Resistance Genes in Different Biological Treatment Systems

Due to the irrational use of antibiotics, antibiotic resistance genes are widely present in the environmental media of our lives. Antibiotics have potential environmental and public health risks, and they bring harm to the environment in which we live. Sewage treatment plants are antibiotic resistance genes’ repository and important process for removing antibiotic resistance genes. The different processes they use in sewage treatment plants, the effect of removing antibiotic resistance genes is also different. In order to discuss the impact of different processes on the removal of antibiotic resistance genes, we selected three wastewater treatment plant samples with different treatment processes for testing, and used the fluorescence quantitative analysis technology of 16SrRNA gene to study the abundance, distribution and diversity of antibiotic resistance genes in different treatment processes. The results showed that the AAO process, the oxidation ditch process, and the CASS process all have high removal effect on antibiotic resistance genes, they all can reduce the diversity and abundance of antibiotic resistance genes, and the oxidation ditch process is the best process of the three treatment processes.