Chapters authored
Biofilm and Quorum Sensing in Helicobacter pylori
Helicobacter pylori (H. pylori) is a gram-negative bacterium living in the human gastrointestinal tract considered as the most common cause of gastritis. H. pylori was listed as the main risk factor for gastric cancer. Triple therapy consisting of a proton pump inhibitor and combinations of antibiotics is the main treatment used. However, this line of therapy has proven less effective mainly due to biofilm formation. Bacteria can regulate and synchronize the expression of multiple genes involved in virulence, toxin production, motility, chemotaxis, and biofilm formation by quorum sensing (QS), thus contributing to antimicrobial resistance. Henceforth, the inhibition of QS called quorum quenching (QQ) is a promising target and alternative to fight H. pylori resistance to antimicrobials. Many phytochemicals as well as synthetic compounds acting as quorum quenchers in H. pylori were described in vitro and in vivo. Otherwise, many other compounds known as quorum quenchers in other species and inhibitors of biofilm formation in H. pylori could act as quorum quenchers in H. pylori. Here, we summarize and discuss the latest findings on H. pylori’s biofilm formation, QS sensing, and QQ mechanisms.
Part of the book: Focus on Bacterial Biofilms
Understanding the Omicron Variant in the COVID-19 Pandemic
The proposed chapter aims to provide an overview of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant and its potential effects on public health. The origins of coronavirus disease of 2019 (COVID-19) pandemic and the SARS-CoV-2 virus evolution through time will be briefly covered at the beginning of the chapter with an emphasis on the emergence of new variants. The next section will present an overview of Omicron, outlining where it was first identified, the key mutations that set it apart from prior variants, and how it has spread worldwide. In the following section, we will briefly discuss the evidence regarding Omicron’s rapid spread in comparison to other COVID-19 variants along with any possible implications in disease severity and hospitalization rates. The chapter also explores how Omicron could affect natural immunity and vaccination efficiency and will provide information on recent studies on the effectiveness of COVID-19 vaccines against Omicron. Finally, we will discuss public health responses to Omicron’s emergence and outline the effective strategies that can lessen its effects.
Part of the book: New COVID-19 Variants