RESUMEN
Introducción: La cuantificación de SARS-CoV-2 en aguas residuales es una herramienta que permite determinar la tendencia de la circulación viral en un área geográfica determinada. Objetivo: Cuantificar el virus SARS-CoV-2 en 15 plantas de tratamiento de aguas residuales en diferentes ciudades de Chile para establecer una comparación con las variables de: i) casos activos por cada 100.000 habs.; ii) positividad diaria (casos nuevos); y iii) fases del plan de confinamiento. Metodología: SARS-CoV-2 se concentró a partir de muestras de aguas residuales. Para obtener el número de genomas del virus por litro se realizó una cuantificación absoluta utilizando qRT-PCR. Resultados: Entre enero y junio de 2021 se procesaron 253 muestras, siendo todas positivas para la presencia del virus. Asimismo, se logró determinar que la tasa de casos activos por cada 100.000 habs. es la variable que mejor se ajusta a las tendencias obtenidas con la cuantificación de la carga viral en las aguas residuales. Conclusiones: La cuantificación de SARS-CoV-2 en las aguas residuales de manera permanente es una herramienta eficiente para determinar la tendencia del virus en un área geográfica determinada y, en conjunto con una vigilancia genómica, puede constituirse en una vigilancia centinela ideal generando alertas sobre futuros brotes.
Background: The quantification of SARS-CoV-2 in wastewater is a tool that allows determining the trend of viral circulation in a particular geographical area. Aim: To quantify the SARS-CoV-2 virus in 15 wastewater treatment plants in different Chilean cities to establish a comparison with the variables of: i) Active cases per 100,000 inhabitants; ii) daily positivity (novel cases); and iii) phases of the lockdown strategy. Methods: SARS-CoV-2 was concentrated from wastewater samples. To obtain the number of virus genomes per liter, absolute quantification was performed using qRT-PCR. Results: Between January and June 2021, 253 samples were processed, all of which were positive for the presence of the virus. Likewise, it will be determined that the rate of active cases per 100,000 inhabitants is the variable that best fits the trends obtained with the quantification of the viral load in wastewater. Conclusions: The quantification of SARS-CoV-2 in wastewater as a continuous strategy is an efficient tool to determine the trend of the viral circulation in a delimited geographical area and, combined with genomic surveillance, it can constitute an ideal sentinel surveillance alert on future outbreaks.
RESUMEN
Wastewater-Based Epidemiology is a tool to face and mitigate COVID-19 outbreaks by evaluating conditions in a specific community. This study aimed to analyze the microbiome profiles using nanopore technology for full-length 16S rRNA sequencing in wastewater samples collected from a penitentiary (P), a residential care home (RCH), and a quarantine or health care facilities (HCF). During the study, the wastewater samples from the RCH and the P were negative for SARS-CoV-2 based on qPCRs, except during the fourth week when was detected. Unexpectedly, the wastewater microbiome from RCH and P prior to week four was correlated with the samples collected from the HCF, suggesting a core bacterial community is expelled from the digest tract of individuals infected with SARS-CoV-2. The microbiota of wastewater sample positives for SARS-CoV-2 was strongly associated with enteric bacteria previously reported in patients with risk factors for COVID-19. We provide novel evidence that the wastewater microbiome associated with gastrointestinal manifestations appears to precede the SARS-CoV-2 detection in sewage. This finding suggests that the wastewaters microbiome can be applied as an indicator of community-wide SARS-CoV-2 surveillance.