Biology subjects

Sotto, A.

Publications and source records attributed to Sotto, A..

3 recordsLinked to original sources

bioRxiv2025

The Staphylococcus aureus prophage-encoded SSBP attenuates virulence and enhances IL-6-mediated macrophage clearance

Pathogens often manipulate host immune responses to promote infection. Here, we describe a novel mechanism by which a secreted prophage-encoded single-stranded DNA-binding protein (SSBP) attenuates Staphylococcus aureus virulence while enhancing host immune defenses. SSBP, encoded by the ROSA-like prophage in a colonizing, reduced-virulence strain of S. aureus (NSA1385), significantly increases bacterial susceptibility to macrophage-mediated killing in vitro and reduces pathogenicity in a zebrafish infection model. Treatment with purified recombinant SSBP decreases bacterial survival within macrophages and demonstrates therapeutic potential. Notably, SSBP activates macrophages via interleukin-6 (IL-6), a pro-inflammatory cytokine that promotes bacterial clearance and macrophage activation. These findings uncover an unexpected prophage-derived mechanism in a colonizing S. aureus strain that attenuates virulence while stimulating host immunity, offering promising avenues for anti-infective therapies and immunomodulatory strategies.

microbiology↗

bioRxiv2021

SARS-CoV-2 wildlife surveillance in Ontario and Quebec, Canada

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the COVID-19 pandemic, is capable of infecting a variety of wildlife species. Wildlife living in close contact with humans are at an increased risk of SARS-CoV-2 exposure and if infected have the potential to become a reservoir for the pathogen, making control and management more difficult. ObjectiveTo conduct SARS-CoV-2 surveillance in urban wildlife from Ontario and Quebec, Canada, increasing our knowledge of the epidemiology of the virus and our chances of detecting spillover from humans into wildlife. MethodsUsing a One Health approach, we leveraged activities of existing research, surveillance, and rehabilitation programs among multiple agencies to collect samples from 776 animals from 17 different wildlife species between June 2020 and May 2021. Samples from all animals were tested for the presence of SARS-CoV-2 viral RNA, and a subset of samples from 219 animals across 3 species (raccoons, Procyon lotor; striped skunks, Mephitis mephitis; and mink, Neovison vison) were also tested for the presence of neutralizing antibodies. ResultsNo evidence of SARS-CoV-2 viral RNA or neutralizing antibodies was detected in any of the tested samples. ConclusionAlthough we were unable to identify positive SARS-CoV-2 cases in wildlife, continued research and surveillance activities are critical to better understand the rapidly changing landscape of susceptible animal species. Collaboration between academic, public and animal health sectors should include experts from relevant fields to build coordinated surveillance and response capacity.

pathology↗

bioRxiv2020

Proteotyping SARS-CoV-2 virus from nasopharyngeal swabs: a proof-of-concept focused on a 3 min mass spectrometry window

Rapid but yet sensitive, specific and high-throughput detection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in clinical samples is key to diagnose infected people and to better control the spread of the virus. Alternative methodologies to PCR and immunodiagnostic that would not require specific reagents are worth to investigate not only for fighting the COVID-19 pandemic, but also to detect other emergent pathogenic threats. Here, we propose the use of tandem mass spectrometry to detect SARS-CoV-2 marker peptides in nasopharyngeal swabs. We documented that the signal from the microbiota present in such samples is low and can be overlooked when interpreting shotgun proteomic data acquired on a restricted window of the peptidome landscape. Simili nasopharyngeal swabs spiked with different quantities of purified SARS-CoV-2 viral material were used to develop a nanoLC-MS/MS acquisition method, which was then successfully applied on COVID-19 clinical samples. We argue that peptides ADETQALPQR and GFYAQGSR from the nucleocapsid protein are of utmost interest as their signal is intense and their elution can be obtained within a 3 min window in the tested conditions. These results pave the way for the development of time-efficient viral diagnostic tests based on mass spectrometry.

microbiology↗