Biofilm as a supracellular organization of pathogenic bacteria

Abstract

The high frequency of resistance to antibiotics among bacterial clinical isolates necessitates the discovery of new targets for suppressing the pathogenicity of microbes without stimulating their resistance. The studied sources suggest that this can be achieved by targeting the determinants of virulence. The search for new active substances with anti-biofilm activity based on the analysis of literature data on the structure of bacterial biofilms, mechanisms of their resistance to antimicrobial agents was the purpose of this work. An electronic search was conducted in Medline (PubMed interface), Scopus, and Web of Science between 2011 and July, 2024 using the keywords: biofilms, antibiotic resistance, Quorum sensing, persisters. 30 sources were selected, 85 were processed. The subject of the search was: microbial landscape of hospital strains of microorganisms, biofilm formation by microorganisms – pathogens of infectious diseases, regulation of virulence factors in bacterial biofilm. Studies of recent years have established that many pathogenic bacteria produce signal molecules for cellular communication. This signaling system is called Quorum sensing (QS) and it depends on the density of the bacterial population and is mediated by signaling molecules called pheromones or autoinducers (AI). Bacteria use QS to regulate activities and behavior including competence, conjugation, symbiosis, virulence, motility, sporulation, antibiotic production and biofilm formation. Researches aimed at bacterial communicative signals and suppressing QS demonstrate a fundamental approach to forming competitive microbial communication. The search, synthesis, and development of drugs based on modified autoinducers of various natures can lead to a breakthrough in the field of antibacterial therapy of infectious diseases, as well as surgical purulent postoperative complications. The pro­cessed literature describes a number of hypotheses regarding the participation of "toxin-antitoxin" systems that control the growth and metabolism of bacteria in the stimulation of the formation of persister cells. The simultaneous acquisition of resistance to many antibacterial factors, including physico-chemical ones, is suggested. Therefore, there is an increased attention of scientists to the study of the anti-biofilm effect of new compounds and drugs capable of influencing energy or metabolic processes in cells, as well as substances that do not require a metabolically active target. The review illustrates general modern approaches to the use of QS chains in pathogenic bacteria as new therapeutic targets.