Role of S. salivarius K12 in the prevention of URTI and AGE in nursery-aged children

Abstract: © This document is protected by international copyright laws. No additional reproduction is authorized. It is permitted for personal use to download and save only one file and print only one copy of this Article. It is not permitted to make additional copies (either sporadically or systematically, either printed or electronic) of the Article for any purpose. It is not permitted to distribute the electronic copy of the article through online internet and/or intranet file sharing systems, electronic mailing or any other means which may allow access to the Article. The use of all or any part of the Article for any Commercial Use is not permitted. The creation of derivative works from the Article is not permitted. The production of reprints for personal or commercial use is not permitted. It is not permitted to remove, cover, overlay, obscure, block, or change any copyright notices or terms of use which the Publisher may post on the Article. It is not permitted to frame or use framing techniques to enclose any trademark, logo, or other proprietary information of the Publisher. COPYRIGHT 2023 EDIZIONI MINERVA MEDICA LETTERS TO THE EDITOR © 2023 ediZiONi MiNerVa Medica Online version at https://www.minervamedica.it Minerva Medica 2023 Sep 28 dOi: 10.23736/S0026-4806.23.08920-6 role of S. salivarius K12 in the prevention of UrTi and aGe in nursery-aged children acute upper respiratory tract infections (UrTis) in children are a major cause of morbidity, absence from daily life and are among the most common reasons for pediatrician visits.1, 2 any intervention that could prevent them would deliver important life-saving and costeffective impacts. despite their wide clinical use, the evidence-based indications of probiotics are narrow and mostly focus on the treatment of acute gastroenteritis (aGe).3 indeed, the potential ability of probiotics to influence and stabilize the gut microbiota, improving its resistance to colonization, supports their rational use.4 although the evidence for ability of probiotics to also modulate immune functions is thought to be modest, it should nonetheless make the case for probiotics to play a possible role in preventing and/or reducing the symptoms of upper respiratory diseases.5 To date, strains from Lactobacillus and Bifidobacterium spp. are the most common probiotics used to treat a wide range of diseases, ailments and conditions that affect humans and animals.6 Much less common is the possibility of resorting to different bacterial species, such as Enterococcus faecium, endowed with well-documented clinical anti-UrTi and anti-aGe properties.7 among the species less widely used as probiotics, the oral commensal Streptococcus salivarius (Ss) is among the best studied, with particular reference to the K12 strain.8 This strain has been widely investigated, especially for its effective action in fighting ear, oral, pharyngeal, and tonsillar infections caused by S. pyogenes, S. pneumoniae, M. catarrhalis, and/or H. influenzae.9 The effectiveness of the Ss K12 is more commonly traced back to its ability to release two antibiotics (Salivaricin a2 and Salivaricin B), which are effective at damaging the membrane of the target bacteria.10 However, the capacity of Ss K12 to counteract bacterial antagonists is not limited to the release of bacteriocins. Other microbial species, nonsensitive to salivaricins a2 and B, including oral-pharyngeal viruses (syncytial virus, adenovirus, rhinovirus), fungi such as Candida, or..