Genomic surveillance reveals early detection and transition of delta to omicron lineages of SARS-CoV-2 variants in wastewater treatment plants of Pune, India.

The COVID-19 pandemic has emphasized the urgency for rapid public health surveillance methods to detect and monitor the transmission of infectious diseases. The wastewater-based epidemiology (WBE) has emerged as a promising tool for proactive analysis and quantification of infectious pathogens within a population before clinical cases emerge. In the present study, we aimed to assess the trend and dynamics of SARS-CoV-2 variants using a longitudinal approach. Our objective included early detection and monitoring of these variants to enhance our understanding of their prevalence and potential impact. To achieve our goals, we conducted real-time quantitative polymerase chain reaction (RT-qPCR) and Illumina sequencing on 442 wastewater (WW) samples collected from 10 sewage treatment plants (STPs) in Pune city, India, spanning from November 2021 to April 2022. Our comprehensive analysis identified 426 distinct lineages representing 17 highly transmissible variants of SARS-CoV-2. Notably, fragments of Omicron variant were detected in WW samples prior to its first clinical detection in Botswana. Furthermore, we observed highly contagious sub-lineages of the Omicron variant, including BA.1 (~28%), BA.1.X (1.0-72%), BA.2 (1.0-18%), BA.2.X (1.0-97.4%) BA.2.12 (0.8-0.25%), BA.2.38 (0.8-1.0%), BA.2.75 (0.01-0.02%), BA.3 (0.09-6.3%), BA.4 (0.24-0.29%), and XBB (0.01-21.83%), with varying prevalence rates. Overall, the present study demonstrated the practicality of WBE in the early detection of SARS-CoV-2 variants, which could help track future outbreaks of SARS-CoV-2. Such approaches could be implicated in monitoring infectious agents before they appear in clinical cases.

Comparative evaluation of advanced oxidation processes (AOPs) for reducing SARS-CoV-2 viral load from campus sewage water.

Presence of SARS-CoV-2 in wastewater is a major concern as the wastewater meets rivers and other water bodies and is used by the population for various purposes. Hence it is very important to treat sewage water in an efficient manner in order to reduce the public health risk. In the present work, various advanced oxidation processes (AOPs) have been evaluated for disinfection of SARS-CoV-2 from sewage water collected from STP inlet of academic institutional residential. The sewage water was subjected to ten AOPs, which include Ozone (O3), Hydrodynamic cavitation (HC), Ultraviolet radiation (UV), and their hybrid combinations like HC/O3, HC/O3/H2O2, HC/H2O2, O3/UV, UV/H2O2, UV/H2O2/O3, and O3/H2O2 to reduce SARS-CoV-2 viral load. Further, AOP treated sewage water was subjected to total nucleic acid isolation followed by RT-qPCR for viral load estimation. The sewage water treatment techniques were evaluated based on their viral concentration-reducing efficiency. It was found that ozone and ozone-coupled hybrid AOPs showed the most promising result with more than 98 % SARS-CoV-2 viral load reducing efficiency from sewage water. Interestingly, the best six AOPs used in this study significantly reduced both the SARS-CoV-2 and PMMoV (faecal indicator) viral load and improved water quality in terms of increasing DO and decreasing TOC.

Predatory activity of Acanthamoeba sp genotype T4 on different plant growth-promoting bacteria and their combined effect on rice seedling growth.

Heterotrophic protists play a crucial role in plant growth promotion via nutrient cycling and shift in microbial community composition in the soil ecosystem. Selective predation pressure by protists contributes to the evaluation of plant beneficial traits in rhizospheric bacteria. However, not always all plant growth-promoting bacterial (PGPB) strains are benefitted by predation. This study aimed to examine the predatory effect of Acanthamoeba sp genotype T4 on a range of PGPB strains and their combined impact on early rice seedling growth. Acanthamoeba sp isolated from rice rhizosphere soils were used to assess predation against several PGPB such as Pseudomonas, Bacillus, Enterobacter, Morganella, Stenotrophomonas, Providencia, and Lysinibacillus on Nutrient Yeast Extract agar (NYE) plate. The controlled experiment on the germinated rice seeds (Oryza sativa L.) grown in Petri dishes containing each PGPB strain and Acanthamoeba sp was performed to evaluate the combined impact on plant performance. The PGPB-Acanthamoeba combined treatments in Petri dishes showed significant rice seedling growth compared to PGPB alone, non-PGPB and control. Our results indicated the positive but different impact of Acanthamoeba sp with different PGPB species on early rice plant growth. Further in-depth research should be carried out with diverse protists and PGPB species to assess which protist species can be linked to enhancement of indigenous soil PGPB for improved plant growth.