About this Research Topic
The interest of the scientific community in bacteria has been traditionally focused on the prevention of host acute infections. More recently, chronic infections related to a bacterial biofilm mode of growth or micro-colonies on host cells have gained importance. However, it is still debatable whether bacterial colonization of various human niches in absence of evident clinical manifestation has to be simply considered as saprophytic microbiota or, instead, as an occurrence that has to be taken into account by a medical point of view.
It is now accepted that bacterial colonization due to biofilm are responsible for a number of chronic or recurrent diseases (e.g.: gingivitis, pyorrhea, prostatitis, otitis media, endocarditis, infections in patients affected by cystic fibrosis or with chronic wounds, cardiovascular devices or prosthetic joints). On the other hand, a common case such as S. aureus nares colonization tends to be generally considered as a phenomenon without any pathologic implication. Based on the most recent microbiological knowledge regarding bacterial growth and host-pathogen interaction, we could speculate whether the hypothesis that asymptomatic bacterial colonization may be related to chronic diseases can be completely ruled out or not. It has been reported that a number of bacterial virulence factors (e.g.: protein A of S. aureus, SLO of S. pyogenes, or FimH of E. coli), lipopolysaccharide produced by Gram-negative bacteria and lipoteichoic acids produced by Gram-positive bacteria, are involved in leukotriene and cysteinyl leukotriene production, potent inflammatory mediators which have been demonstrated to be part of the pathogenesis of chronic diseases such as for example asthma. In this respect, we recently reported a possible association between Streptococus pyogenes colonization of tonsils and cases of pediatric obstructive sleep apnea syndrome.
The aim of this Research Topic is to accumulate evidences on and to stimulate the investigation of possible pathogenic mechanisms involved in chronic disease associated with bacteria, throughout the study of bacterial colonization in different niches, spanning from oral and nasopharyngeal environment to skin and gut milieu. We intend to highlight a still poorly investigated field, which we think of a potential great interest for human well-being.
Keywords: Bacterial colonization, Chronic infectiuos diseases, Biofilm, Flora, Host-pathogen interaction
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