Analysis of chlorhexidine, antibiotics and bacterial community composition in water environments from Brazil, Cameroon and Madagascar during the COVID-19 pandemic.

The widespread of chlorhexidine and antibiotics in the water bodies, which grew during the global COVID-19 pandemic, can increase the dispersion of antibiotic resistance. We assessed the occurrence of these pharmaceutical compounds as well as SARS-CoV-2 and analysed the bacterial community structure of hospital and urban wastewaters from Brazil, Cameroon, and Madagascar. Water and wastewater samples (n = 59) were collected between January-June 2022. Chlorhexidine, azithromycin, levofloxacin, ceftriaxone, gentamicin and meropenem were screened by Ultra-High-Performance Liquid Chromatography coupled with mass spectrometer. SARS-CoV-2 was detected based on the nucleocapsid gene (in Cameroon and Madagascar), and envelope and spike protein-encoding genes (in Brazil). The total community-DNA was extracted and used for bacterial community analysis based on the 16S rRNA gene. To unravel likely interaction between pharmaceutical compounds and/or SARS-CoV-2 with the water bacterial community, multivariate statistics were performed. Chlorhexidine was found in hospital wastewater effluent from Brazil with a maximum concentration value of 89.28 µg/L. Additionally, antibiotic residues such as azithromycin and levofloxacin were also present at concentrations between 0.32-7.37 µg/L and 0.11-118.91 µg/L, respectively. In Cameroon, azithromycin was the most found antibiotic present at concentrations from 1.14 to 1.21 µg/L. In Madagascar instead, ceftriaxone (0.68-11.53 µg/L) and levofloxacin (0.15-0.30 µg/L) were commonly found. The bacterial phyla statistically significant different (P < 0,05) among participating countries were Proteobacteria, Patescibacteria and Dependentiae which were mainly abundant in waters sampled in Africa and, other phyla such as Firmicutes, Campylobacterota and Fusobacteriota were more abundant in Brazil. The phylum Caldisericota was only found in raw hospital wastewater samples from Madagascar. The canonical correspondence analysis results suggest significant correlation of azithromycin, meropenem and levofloxacin with bacteria families such as Enterococcaceae, Flavobacteriaceae, Deinococcaceae, Thermacetogeniaceae and Desulfomonilaceae, Spirochaetaceae, Methanosaetaceae, Synergistaceae, respectively. Water samples were also positive for SARS-CoV-2 with the lowest number of hospitalized COVID-19 patients in Madagascar (n = 7) and Brazil (n = 30). Our work provides new data about the bacterial community profile and the presence of pharmaceutical compounds in the hospital effluents from Brazil, Cameroon, and Madagascar, whose limited information is available. These compounds can exacerbate the spreading of antibiotic resistance and therefore pose a risk to public health.

Human microbiota drives hospital-associated antimicrobial resistance dissemination in the urban environment and mirrors patient case rates.

BACKGROUND: The microbial community composition of urban environments is primarily determined by human activity. The use of metagenomics to explore how microbial communities are shaped in a city provides a novel input that can improve decisions on public health measures, architectural design, and urban resilience. Of note, the sewage system in a city acts as a complex reservoir of bacteria, pharmaceuticals, and antimicrobial resistant (AMR) genes that can be an important source of epidemiological information. Hospital effluents are rich in patient-derived bacteria and can thus readily become a birthplace and hotspot reservoir for antibiotic resistant pathogens which are eventually incorporated into the environment. Yet, the scope to which nosocomial outbreaks impact the urban environment is still poorly understood. RESULTS: In this work, we extensively show that different urban waters from creeks, beaches, sewage spillways and collector pipes enclose discrete microbial communities that are characterized by a differential degree of contamination and admixture with human-derived bacteria. The abundance of human bacteria correlates with the abundance of AMR genes in the environment, with beta-lactamases being the top-contributing class to distinguish low vs. highly-impacted urban environments. Indeed, the abundance of beta-lactamase resistance and carbapenem resistance determinants in the urban environment significantly increased in a 1-year period. This was in line with a pronounced increase of nosocomial carbapenem-resistant infections reported during the same period that was mainly driven by an outbreak-causing, carbapenemase-producing Klebsiella pneumoniae (KPC) ST-11 strain. Genome-resolved metagenomics of urban waters before and after this outbreak, coupled with high-resolution whole-genome sequencing, confirmed the dissemination of the ST-11 strain and a novel KPC megaplasmid from the hospital to the urban environment. City-wide analysis showed that geospatial dissemination of the KPC megaplasmid in the urban environment inversely depended on the sewage system infrastructure. CONCLUSIONS: We show how urban metagenomics and outbreak genomic surveillance can be coupled to generate relevant information for infection control, antibiotic stewardship, and pathogen epidemiology. Our results highlight the need to better characterize and understand how human-derived bacteria and antimicrobial resistance disseminate in the urban environment to incorporate this information in the development of effluent treatment infrastructure and public health policies. Video Abstract.

Challenges on solar oxidation as post-treatment of municipal wastewater from UASB systems: Treatment efficiency, disinfection and toxicity.

The application of solar photo-Fenton as post-treatment of municipal secondary effluents (MSE) in developing tropical countries is the main topic of this review. Alternative technologies such as stabilization ponds and upflow anaerobic sludge blanket (UASB) are vastly applied in these countries. However, data related to the application of solar photo-Fenton to improve the quality of effluents from UASB systems are scarce. This review gathered main achievements and limitations associated to the application of solar photo-Fenton at neutral pH and at pilot scale to analyze possible challenges associated to its application as post-treatment of MSE generated by alternative treatments. To this end, the literature review considered studies published in the last decade focusing on CECs removal, toxicity reduction and disinfection via solar photo-Fenton. Physicochemical characteristics of effluents originated after UASB systems alone and followed by a biological post-treatment show significant difference when compared with effluents from conventional activated sludge (CAS) systems. Results obtained for solar photo-Fenton as post-treatment of MSE in developed countries indicate that remaining organic matter and alkalinity present in UASB effluents may pose challenges to the performance of solar advanced oxidation processes (AOPs). This drawback could result in a more toxic effluent. The use of chelating agents such as Fe3+-EDDS to perform solar photo-Fenton at neutral pH was compared to the application of intermittent additions of Fe2+ and both of these strategies were reported as effective to remove CECs from MSE. The latter strategy may be of greater interest in developing countries due to costs associated to complexing agents. In addition, more studies are needed to confirm the efficiency of solar photo-Fenton on the disinfection of effluent from UASB systems to verify reuse possibilities. Finally, future research urges to evaluate the efficiency of solar photo-Fenton at natural pH for the treatment of effluents from UASB systems.

Study on the Effectiveness of Two Biopolymer Coagulants on Turbidity and Chemical Oxygen Demand Removal in Urban Wastewater.

The present study investigated the effectiveness of two biopolymer coagulants on turbidity and chemical oxygen demand removal in urban wastewater. The biopolymers were produced from vegetal biomass using the mucilage extracted from Opuntia robusta cladodes, and Uncaria tomentosa leaves. Opuntia robusta is an abundant species in Mexico, which is not edible. Uncaria tomentosa is an exotic invasive species in Mexico and other countries, which negatively affects the ecosystems where it is introduced. A combined experimental design of mixture-process was selected to evaluate the effectiveness of both biopolymer coagulants regarding aluminum sulfate (conventional chemical coagulant). Results showed turbidity and chemical oxygen demand removal efficiencies of 42.3% and 69.6% for Opuntia robusta and 17.2% and 39.4% for Uncaria tomentosa biopolymer coagulant, respectively, at a dose of 200 mg/L. Furthermore, optimum conditions from the experimental design to reach the maximum turbidity and chemical oxygen demand removal were obtained at an Opuntia robusta biopolymer coagulant concentration of 10 mg/L, showing removal efficiencies of 68.7 ± 1.7% and 86.1 ± 1.4%, respectively. These results support using Opuntia robusta as an alternative biopolymer coagulant in urban wastewater treatment.

Long-term semi-continuous production of carbohydrate-enriched microalgae biomass cultivated in low-loaded domestic wastewater.

The production of carbohydrate-enriched biomass from waste streams as a sustainable biofuel precursor is a noteworthy endeavor. This study investigates the long-term microalgae cultivated under low domestic wastewater loads and different hydraulic retention times (HRT) in a semi-continuous photobioreactor. The influence of operational conditions, the microalgae interaction with carbon, nutrients availability, and microbial population in terms of carbohydrate content were elucidated. The results revealed that the operation at similar low nutrients and carbon loads maintained at three different hydraulic retention times (HRT) of 10, 8, and 6 days caused different patterns in nutrients uptake and biomass composition. Particularly, the carbohydrate accumulation was greatly influenced by the unbalance in the N:P ratios than complete depletion of the nutrients. Hence, during the period operated at HRT of 10 d, high nutrients removal efficiencies were observed while gradually increasing carbohydrate content up to 57% in dry cell weight (DCW). Afterward, the decrease to 8 and 6 d of HRT showed lower nutrient consumption with depleted alkalinity, reaching an appreciably high carbohydrate accumulation of up to 46%, and 56%, respectively. The biomass concentration decreased in the order of HRT of 10, 8, and 6 days. This study demonstrated that microalgae adapted to low carbon and nutrient loads could still accumulate high carbohydrate at shorter HRT using domestic wastewater as substrate.

Removal of contaminants of emerging concern (CECs) and antibiotic resistant bacteria in urban wastewater using UVA/TiO2/H2O2 photocatalysis.

The dispersion of pollutants and proliferation of antibiotic resistant bacteria in the aquatic environment are an emerging health concern worldwide. In this sense, it is essential to develop new technologies to increase the quality of wastewater treatment, which is spread throughout the environment. The present study has demonstrated evidence of the existence of antibiotic and mercury-resistant bacteria in the aquatic environment. The application of heterogeneous photocatalysis with UVA/TiO2 P25 slurry (200 mg L-1), UVA/TiO2-immobilized, and UVA/TiO2-immobilized/H2O2 were evaluated for the simultaneous elimination of a mixture of contaminants of emerging concern (acetamiprid (ACP), imazalil (IMZ) and bisphenol A (BPA)) and inactivation of antibiotic and mercury-resistant bacteria (Pseudomonas aeruginosa and Bacillus subtilis). UVA/TiO2-immobilized/H2O2 increased the inactivation and elimination of the contaminants. After the combined treatment, the mixture of BPA, IMZ and ACP decreased 62%, 21% and <5%, respectively, after 300 min at 13.10 kJ L-1 of accumulated UV energy. The Pseudomonas aeruginosa strain was inactivated after 120 min using 5.24 kJ L-1 of accumulated UV energy, whereas the Bacillus subtilis strain was shown to be extremely resistant, with a capacity to develop mechanisms to avoid the oxidation process.

On the performance of electrocatalytic anodes for photoelectro-Fenton treatment of synthetic solutions and real water spiked with the herbicide chloramben.

The destruction of the herbicide chloramben in 0.050 M Na2SO4 solutions at natural pH has been studied by photoelectro-Fenton with UVA light (PEF). The trials were carried out in a cell equipped with an air-diffusion cathode for H2O2 generation and different electrocatalytic anodes, namely active IrO2-based and RuO2-based electrodes and non-active boron-doped diamond (BDD) and PbO2 ones. Similar removal rates were found regardless of the anode nature because the herbicide was mainly oxidized by OH formed from Fenton's reaction, which was enhanced by UVA-induced photo-Fenton reaction. The use of an IrO2-based anode led to almost total mineralization at high current density, as also occurred with the powerful BDD anode, since photoactive intermediates originated from OH-mediated oxidation were degraded under irradiation with UVA light. The good performance of the IrO2-based anode in PEF was confirmed at different current densities and herbicide concentrations. The presence of Cl- in the medium caused a slight deceleration of herbicide removal as well as mineralization inhibition, owing to the production of active chlorine with consequent formation of persistent chloroderivatives. Seven aromatic products along with oxalic and oxamic acids were identified in sulfate medium. Five aromatic derivatives were detected in Cl--containing matrix, corroborating the generation of organochlorine compounds. In secondary effluent, larger mineralization was achieved by PEF with a BDD anode due to its high oxidation ability to destroy the chloroderivatives, although an acceptable performance was also obtained using an IrO2-based anode.

Performance of an integrated system combining microalgae and vertical flow constructed wetlands for urban wastewater treatment.

The present study investigated the performance of an integrated system, combining the sequential use of microalgae (MA) and vertical flow constructed wetland (VFCW) for the treatment of wastewaters produced at a university campus. Ecotoxicity and phytotoxicity assays were performed using respectively Daphnia magna and Lactuca sativa, whereas the genotoxicity of the wastewaters was assessed by using D. magna and Allium cepa. The results revealed that the major environmental impacts of the studied wastewaters are associated with the high eutrophication potential, due to high N-NH3 (68.8 ± 25.7 mg L-1), total P (7.71 ± 2.5 mg L-1), and BOD5 (526.4 ± 177 mg L-1) values, pathogenic load, and genototoxicity (p < 0.0001). The results also showed that the integrated system (MA + VFCW) was not able to satisfactory reduce the total p values (only 4%). Nevertheless, the MA + VFCW system achieved very promising results for the nitrogen removal, with emphasis on N-NH3 removal (100%) and the highest BOD5 removal (57%). Neither the raw wastewaters nor the treated wastewaters were phytotoxic. The integrated system completely eliminated the ecotoxicity (100%) and genotoxicity (n.s.) of the raw wastewater and showed decontamination potential. Thus, the integrated system emerges as an innovative environmental technology and, with minor adjustments, might be efficiently used in large scale and eventually replace conventional wastewater treatment systems.

Distribution and genetic diversity of the human polyomaviruses JC and BK in surface water and sewage treatment plant during 2009 in Porto Alegre, Southern Brazil / Distribuição e diversidade genética dos poliomavírus humanos JC e BK em águas superficiais e de estação de tratamento de esgoto durante 2009 em Porto Alegre, sul do Brasil

Abstract The human polyomaviruses JC and BK (JCPyV and BKPyV) are ubiquitous, species-specific viruses that belong to the family Polyomaviridae. These viruses are known to be excreted in human urine, and they are potential indicators of human wastewater contamination. In order to assess the distribution of both JCPyV and BKPyV in urban water samples collected from a sewage treatment plant (STP) and from a canalized water stream of Porto Alegre, Brazil, two nested-PCR assays were optimized and applied to the samples collected. The amplicons obtained were submitted to sequencing, and the sequences were analyzed with sequences of human polyomaviruses previously deposited in GenBank. Twelve out of 30 water samples (40%) were JCPyV positive, whereas six samples (20%) were BKPyV positive. The sequencing results confirmed the presence of JCPyV subtypes 1 and 3, whereas only BKPyV Ia and Ib were found. This study shows for the first time the presence of human polyomaviruses in surface water and in samples collected in a sewage treatment plant in southern Brazil.

Resumo Os poliomavírus humanos JC e BK (JCPyV e BKPyV) são virus ubíquos, espécie-específicos, pertencentes à família Polyomaviridae. Estes vírus são conhecidos por serem excretados pela urina humana, sendo considerados potenciais indicadores de contaminação por águas residuais urbanas. Buscando acessar a distribuição de JCPyV e BKPyV em amostras de águas coletadas de uma estação de tratamento de esgoto e de um arroio canalizado de Porto Alegre, Brasil, duas técnicas de nested-PCR foram otimizadas e aplicadas às amostras coletadas. Os amplificados obtidos foram submetidos ao sequenciamento e suas sequências analisadas com base em sequências de poliomavírus humanos previamente depositadas no GenBank. Doze de 30 amostras de água (40%) foram positivas para JCPyV, enquanto 6 amostras (20%) foram positivas para BKPyV. Os resultados do sequenciamento confirmaram a presença dos subtipos 1 e 3 de JCPyV, enquanto apenas os BKPyV Ia e Ib foram encontrados. Este estudo demonstra pela primeira vez a presença de poliomavírus humanos em águas superficiais e em amostras coletadas em uma estação de tratamento de esgoto na região sul do Brasil.

Distribution and genetic diversity of the human polyomaviruses JC and BK in surface water and sewage treatment plant during 2009 in Porto Alegre, Southern Brazil

Abstract The human polyomaviruses JC and BK (JCPyV and BKPyV) are ubiquitous, species-specific viruses that belong to the family Polyomaviridae. These viruses are known to be excreted in human urine, and they are potential indicators of human wastewater contamination. In order to assess the distribution of both JCPyV and BKPyV in urban water samples collected from a sewage treatment plant (STP) and from a canalized water stream of Porto Alegre, Brazil, two nested-PCR assays were optimized and applied to the samples collected. The amplicons obtained were submitted to sequencing, and the sequences were analyzed with sequences of human polyomaviruses previously deposited in GenBank. Twelve out of 30 water samples (40%) were JCPyV positive, whereas six samples (20%) were BKPyV positive. The sequencing results confirmed the presence of JCPyV subtypes 1 and 3, whereas only BKPyV Ia and Ib were found. This study shows for the first time the presence of human polyomaviruses in surface water and in samples collected in a sewage treatment plant in southern Brazil.

Resumo Os poliomavírus humanos JC e BK (JCPyV e BKPyV) são virus ubíquos, espécie-específicos, pertencentes à família Polyomaviridae. Estes vírus são conhecidos por serem excretados pela urina humana, sendo considerados potenciais indicadores de contaminação por águas residuais urbanas. Buscando acessar a distribuição de JCPyV e BKPyV em amostras de águas coletadas de uma estação de tratamento de esgoto e de um arroio canalizado de Porto Alegre, Brasil, duas técnicas de nested-PCR foram otimizadas e aplicadas às amostras coletadas. Os amplificados obtidos foram submetidos ao sequenciamento e suas sequências analisadas com base em sequências de poliomavírus humanos previamente depositadas no GenBank. Doze de 30 amostras de água (40%) foram positivas para JCPyV, enquanto 6 amostras (20%) foram positivas para BKPyV. Os resultados do sequenciamento confirmaram a presença dos subtipos 1 e 3 de JCPyV, enquanto apenas os BKPyV Ia e Ib foram encontrados. Este estudo demonstra pela primeira vez a presença de poliomavírus humanos em águas superficiais e em amostras coletadas em uma estação de tratamento de esgoto na região sul do Brasil.

Desempeño de una laguna anaerobia con bafle divisor seguida de una laguna facultativa, posible afectación de la salud pública

Esta investigación tuvo como objetivo principal evaluar la eficiencia de la estación para tratamiento de aguas residuales de la ciudad Santa Fé do Sul (São Paulo) y definir posibles efectos en la salud pública producidos por la calidad del efluente final. Se realizó un estudio batimétrico de las lagunas de estabilización anaerobia con bafle divisor y facultativa para formar un perfil de acumulación de lodos; se monitoreó durante 24 horas consecutivas el afluente bruto y los efluentes de las lagunas para diagnosticar el comportamiento de la Estación. La eficiencia media de remoción de la demanda bioquímica de oxígeno fue del 89%, mayor que la mínima eficiencia exigida por la legislación brasilera vigente. La cantidad de coliformes fecales superó en gran medida los valores permitidos; sin embargo, la concentración de sólidos sedimentables cumplió a cabalidad con la norma ambiental presentando valores menores a 1,0 mL/L. Los resultados mostraron que la estación requiere labores de mantenimiento de la laguna anaerobia, así como mayor control operacional y mantenimiento más efectivos. Se evidenció la necesidad de implementar un sistema de pos tratamiento que garantice la reducción de los coliformes fecales del efluente final como medida para disminuir posibles riesgos a la salud pública en la zona de descarga y aguas abajo del punto de vertimiento final.

The main objective in this research was to evaluate the efficiency of the sewage treatment plant of Santa Fé do Sul city (São Paulo) and to define possible effects on public health produced by the final effluent quality. A bathymetric study of the anaerobic with baffle and facultative stabilization ponds was done in order to define the sludge accumulation profile; the raw influents and the lagoons effluents were monitored during 24 consecutive hours to diagnose the Plant performance. The average efficiency of the biochemical oxygen demand was 89%, higher than the minimum efficiency allowed by the Brazilian current legislation. The amount of fecal coliforms highly exceeds the permitted values; however the settleable solids concentration achieved the environmental regulation with values lower than 1, 0 mL/L. The results indicated that the station requires maintenance works at the anaerobic pond, a better operational control and more effective maintenance. It was shown the need to install a post treatment system to guarantee the reduction of the fecal coliforms at the final effluent as an action to diminish the public health possible risks in the discharge zone and downstream of the final dump point.