Evaluation of two molecular detection platforms for gastroenteritis pathogens in treated sewage water in the Eastern province of Saudi Arabia.

The ability to screen environmental water samples for gastroenteritis pathogens, particularly viruses remains challenging. Here, we investigated the presence of enteric viruses in treated sewage effluent water samples collected from a cooling tower in The Kingdom of Saudi Arabia (SA) from 2018 to 2019. Our ultimate aim was to determine the optimal handling and processing conditions for the water samples and the most sensitive detection method for the assessment of viral contamination. Sewage was collected before and after treatment at three defined zones. Samples were concentrated by ultracentrifugation and analyzed using a multiplexed bead-based assay system (Luminex technology) or multiplex PCR (QIAstat-Dx). The efficiency of these modalities to accurately detect virus contamination were subsequently compared. In total, 64 samples (16 controls and four treated samples per-control) were analyzed for 26 enteric pathogens. Of the samples, 98.7% were negative for viruses following treatment. Detection rates were higher for the multiplex PCR (QIAstat-Dx) system compared to the hybridization method, highlighting its higher sensitivity. The current water sewage treatment protocols in KSA could efficiently eradicate viral pathogens, minimizing their potential for waterborne transmission. We provide the first systematic analysis of two molecular detection methods for the assessment of gastroenteritis-associated pathogens from environmental samples in KSA. We conclude that the multiplex PCR (QIAstat-Dx) system outperforms the Luminex technology for the detection of virus pathogens in treated water samples.

HIV-2 Vpx neutralizes host restriction factor SAMHD1 to promote viral pathogenesis.

SAMHD1, a human host factor found in myeloid cells which restricts HIV-1 replication. It depletes the dNTPs pool for viral cDNA syntheses, thus preventing the viral replication in the cells. The viral accessory protein, Vpx, exists only in SIVmac/HIV-2 particles. Vpx in SIVmac can induce proteosomal degradation of SAMHD1, which then leads to a decrease in the cytoplasmic dNTP pool. The protein-protein interaction between Vpx and SAMHD1 and its consequences are still unclear. Methods: In this study, we cloned, for the first time, Vpx gene from a HIV-2 infected patient and found up to 30% sequence variation compared to known HIV-2 strains. We then analyzed the role of SAMHD1 protein expression in transfected THP-1 and U937 cells by transfecting with the Vpx gene derived from SIVmac, HIV-2 from the NIH sample as well as HIV-2 from a Saudi patient. We found that Vpx gene expression led to reduced levels of intracellular SAMHD1. When the supernatants of the transfected cell lines were examined for secreted cytokines, chemokines and growth factors, Vpx expression seemed to be suppressive of pro-inflammatory response, and skewed the immune response towards an anti-inflammatory response. These results suggest that Vpx can act at two levels: clearance of intracellular restriction factor and suppression of cytokine storm: both aimed at long-term latency and host-pathogen stand-off, suggesting that Vpx is likely to be a potential therapeutic target.