Mechanisms and Control Strategies of Antibiotic Resistance in Pathological Biofilms

Abstract

Biofilms are protected microbial structures enclosed by a self-secreted extracellular matrix [1]. Bacteria biofilm is one of the most successful forms of life, being widely distributed in a diversity of environments [2]. All higher organisms (including humans) are colonized by microorganisms that form biofilms, mostly bacteria [3]. The ability of biofilms to escape the host immune system and resist antibiotics poses great health threats to patients [4,5].Biofilm formation contributes to drug resistance and inflammation, causing persistent infections in patients [6]. Biofilms also function as cell reservoirs that can repopulate infection sites after the release of suppression. For example, biofilm formation is a major concern for cystic fibrosis pneumonia caused by Pseudomonas aeruginosa and urinary tract infections caused by Escherichia coli, both of which are refractory to multiple antibiotics [7]. Therefore, basic research on biofilm formation and the mechanism of their resistance is of great clinical relevance. The objective of this review is to summarize the current research progress in antibiotic resistance mechanisms associated with bacterial biofilms and anti-biofilm strategies, which may greatly benefit patients who suffer from biofilm-related infections. Bacterial Biofilms Structure and Characteristics of Bacterial BiofilmThe physical scaffold of a biofilm is the matrix of extracellular polymeric substances (EPSs), self-secreted substances that keep bacterial cells in a contained structure and attach them to surfaces [8]. Most of the biomass of the biofilm is hydrated EPS rather than bacterial cells, which only make up between 2% to 15% of the total biofilm mass [9]. EPS is mostly composed of polysaccharides, proteins, lipids and extracellular DNA (eDNA) (Fig. 1) [9]. Enhanced antimicrobial resistance, nutrient capture and social cooperation are three main characteristic features of biofilms, and the EPS matrix underlies these important properties [2]. The structures of biofilms somewhat resembles tissues of higher organisms, which are structurally complex and highly heterogenous in gene expression [10], both contributing to the resistance mechanisms of biofilm. Life Cycle of Bacterial BiofilmsThe transition from planktonic growth to biofilm is a complex and highly regulated process that follows a few steps (Fig. 1). The first step is the initial attachment of planktic bacterial cells to a surface, which often happens when cells are under environmental stress. The propelling structures, such as appendages, fimbriae and sex pili, Bacterial biofilm is a community of bacteria that are embedded and structured in a self-secreted extracellular matrix. An important clinical-related characteristic of bacterial biofilms is that they are much more resistant to antimicrobial agents than the planktonic cells (up to 1,000 times), which is one of the main causes of antibiotic resistance in clinics. Therefore, infections caused by biofilms are notoriously difficult to eradicate, such as lung infection caused by Pseudom...

Risks and Prevention of Surgical Site Infection After Hernia Mesh Repair and the Predictive Utility of ACS-NSQIP

“…Haematoma or extracellular matrix proteins (fibrinogen, elastin, collagen, fibronectin) on a medical prosthesis such as hernia mesh provide a substrate for Staphylococcal bacterial adhesion via microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). [28][29][30][31][32][33] Biofilm producing organisms such as S. epidermidis have a very strong affinity for fibrinogen via a "dock, lock and latch" mechanism. 28 After adhesion to a prosthetic surface, planktonic bacteria transition to an exponential growth phase, with bacterial production of extracellular polymeric substance (EPS).…”

“…However, reformation and maturation of a biofilm can occur within 3 days of debridement. 32 Re-operation for removal of infected mesh has been reported from weeks to 10 years after hernia mesh repair surgery. 15 In longer term follow-up, the overall successful salvage rate of infected mesh without further episodes of sepsis may be as low as 10%.…”

Biofilm formation and antibiotic resistance of urinary catheter associated bacteria from hospitalized patients, Bangladesh

“…Biofilm-producing bacteria is more resistant to antibiotics than the bacteria that do not form biofilms (Hashemzadeh et al, 2020;Luo et al, 2021). All the biofilm-forming isolates in our study were resistant to multiple antibiotics except for both carbapenems (meropenem and imipenem).…”

Infectious Uveitis in Horses and New Insights in Its Leptospiral Biofilm-Related Pathogenesis

“…The samples from healthy eyes were taken for ethical reasons only after euthanasia of the [468,469] horses or after enucleation (for another reason than ERU); thus, the eyes could not be observed further. It is therefore unknown whether the eyes from which the samples with positive MAT or PCR results were taken would have developed ERU in the course of the following months and years, or whether it had been an asymptomatic infection.…”

“…For the regulation of processes in biofilms, cell-to-cell communication (quorum sensing, QS) takes place [483,485,486]. QS is made possible by signaling molecules, which are secreted to coordinate community behaviors and to defend against unfavorable environmental conditions [468,469]. Within the biofilm scaffold are water-filled channels through which nutrients, metabolites, and other secreted substances can be transported [467,486], and through which QS is performed [484][485][486].…”