1. Diversity of bacteria and bacterial products as antibiofilm and antiquorum sensing drugs against pathogenic bacteriaFazlurrahman Khan, Sandra Oloketuyi, Young-Mog Kim, 2019, pregledni znanstveni članek Opis: The increase in antibiotic resistance of pathogenic bacteria has led to the development of new therapeutic approaches to inhibit biofilm formation as well as interfere quorum sensing (QS) signaling systems. The QS system is a phenomenon in which pathogenic bacteria produce signaling molecules that are involved in cell to cell communication, production of virulence factors, biofilm maturation, and several other functions. In the natural environment, several non-pathogenic bacteria are present as mixed population along with pathogenic bacteria and they control the behavior of microbial community by producing secondary metabolites. Similarly, non-pathogenic bacteria also take advantages of the QS signaling molecule as a sole carbon source for their growth through catabolism with enzymes. Several enzymes are produced by bacteria which disrupt the biofilm architecture by degrading the composition of extracellular polymeric substances (EPS) such as exopolysaccharide, extracellular- DNA and protein. Thus, the interference of QS system by bacterial metabolic products and enzymatic catalysis, modification of the QS signaling molecules as well as enzymatic disruption of biofilm architecture have been considered as the alternative therapeutic approaches. This review article elaborates on the diversity of different bacterial species with respect to their metabolic products as well as enzymes and their molecular modes of action. The bacterial enzymes and metabolic products will open new and promising perspectives for the development of strategies against the pathogenic bacterial infections. Ključne besede: Bacteria, biofilm, quorum sensing, inhibition, metabolites, pathogen, virulence. Objavljeno v RUNG: 18.01.2021; Ogledov: 3546; Prenosov: 0 Gradivo ima več datotek! Več... |
2. Treatment strategies targeting persister cell formation in bacterial pathogensFazlurrahman Khan, Dung Pham, Nazia Tabassum, Sandra Oloketuyi, Young-Mog Kim, 2020, pregledni znanstveni članek Opis: Persister cells are transiently antibiotic-tolerant and dormant subpopulations that are produced to escape the effects of antibiotics within biofilms or planktonic cell populations. Persister cells are of high clinical importance due to their tolerance to antimicrobial agents and subsequent failure in antibiotic treatments. Understanding persister cell formation mechanisms is therefore highly important for developing effective therapeutic strategies against pathogenic bacterial persisters. Several anti-persister compounds have been previously identified via isolation from natural resources or chemical synthesis. Furthermore, a combination of these compounds with antibiotics or non-antibiotic drugs also allows action on multiple targets while reducing the administration frequency. Here, we present a comprehensive overview of the clinical importance and formation mechanisms of persister cells as well as the current treatment strategies against persister cell formations in chronic infections. Ključne besede: Biofilm, anti-persister agents, persister cells, pathogenic bacteria, chronic infections Objavljeno v RUNG: 14.01.2021; Ogledov: 3894; Prenosov: 0 Gradivo ima več datotek! Več... |
3. Molecules involved in motility regulation in Escherichia coli cells: a reviewFazlurrahman Khan, Nazia Tabassum, Dung Pham, Sandra Oloketuyi, Young-Mog Kim, 2020, izvirni znanstveni članek Opis: The initial colonization of the host organism by commensal, probiotic, and pathogenic Escherichia coli strains is an important step in the development of infections and biofilms. Sensing and colonization of host cell surfaces are governed by flagellar and fimbriae/pili appendages, respectively. Biofilm formation confers great advantages on pathogenic E. coli cells such as protection against the host immune system, antimicrobial agents, and several environmental stress factors. The transition from planktonic to sessile physiological states involves several signaling cascades and factors responsible for the regulation of flagellar motility in E. coli cells. These regulatory factors have thus become important targets to control pathogenicity. Hence, attenuation of flagellar motility is considered a potential therapy against pathogenic E. coli. The present review describes signaling pathways and proteins involved in direct or indirect regulation of flagellar motility. Furthermore, application strategies for antimotility natural or synthetic compounds are discussed also. Ključne besede: Biofilm formation, Escherichia coli, inhibition, motility, pathogenesis Objavljeno v RUNG: 14.01.2021; Ogledov: 4874; Prenosov: 0 Gradivo ima več datotek! Več... |
4. Chitosan and their derivatives: Antibiofilm drugs against pathogenic bacteriaFazlurrahman Khan, Dong Pham, Sandra Oloketuyi, Panchanathan Manivasagan, Junghwan Oh, Young-Mog Kim, 2020, pregledni znanstveni članek Opis: Biofilm formed by several pathogenic bacteria results in the development of resistance against antimicrobial compounds. The polymeric materials present in the biofilm architecture hinder the entry of antimicrobial compounds through the surface of bacterial cells which are embedded as well as enclosed beneath the biofilm matrix. Recent and past studies explored the alternative approaches to inhibit the formation of biofilm by different agents isolated from plants, animals, and microbes. Among these agents, chitosan and its derivatives have got more attention due to their properties such as biodegradability, biocompatibility, non-allergenic and non-toxicity. Recent researches have focused on employing chitosan and its derivatives as effective agents to inhibit biofilm formation and attenuate virulence properties by various pathogenic bacteria. Such antibiofilm activity of chitosan and its derivatives can be further enhanced by conjugation with a wide range of bioactive compounds. The present review describes the antibiofilm properties of chitosan and its derivatives against the pathogenic bacteria. This review also summarizes the mechanisms of biofilm inhibition exhibited by these molecules. The knowledge of the antibiofilm activities of chitosan and its derivatives as well as their underlying mechanisms provides essential insights for widening their applications in the future. Ključne besede: Antibiofilm, Biofilm inhibition, Chitosan, Chitosan derivatives, Pathogenic bacteria Objavljeno v RUNG: 14.01.2021; Ogledov: 3204; Prenosov: 0 Gradivo ima več datotek! Več... |
5. Antibiotics and their different application strategies in controlling the biofilm forming pathogenic bacteriaFazlurrahman Khan, Dung T N Pham, Sandra Oloketuyi, Young-Mog Kim, 2020, pregledni znanstveni članek Opis: Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment.
Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm.
Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier.
Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria. Ključne besede: Antibiotics, biofilm inhibition, multiple antibiotics, pathogenic bacteria, resistance mechanism, virulence factors Objavljeno v RUNG: 14.01.2021; Ogledov: 3408; Prenosov: 0 Gradivo ima več datotek! Več... |
6. A future perspective on neurodegenerative diseases: Nasopharygneal and gut microbiotaFazlurrahman Khan, Sandra Oloketuyi, 2016, pregledni znanstveni članek Opis: Neurodegenerative diseases are considered a serious life‐threatening issue regardless of age. Resulting nerve damage progressively affects important activities, such as movement, coordination, balance, breathing, speech and the functioning of vital organs. Reports on the subject have concluded that neurodegenerative disease can be caused by mutations of susceptible genes, alcohol consumption, toxins, chemicals and other unknown environmental factors. Although several diagnostic techniques can be used to determine aetiologies, the process is difficult and often fails. Research shows that nasopharyngeal and gut microbiota play important roles in brain to spinal cord coordination. However, no conclusive epidemiologic evidence is available on the roles played by respiratory and gut microbiota in the development of neurodegenerative diseases. Thus, understanding the connection between respiratory and gut microbiota and the nervous system could provide information on causal links. The present review describes future perspectives on the role played by nasopharyngeal and gut microbiota in the development of neurodegenerative diseases. Ključne besede: culture‐independent, gut, microbiota, nasopharyngeal, neurodegenerative disease Objavljeno v RUNG: 14.01.2021; Ogledov: 2856; Prenosov: 0 Gradivo ima več datotek! Več... |
7. Strategies of biofilm inhibition and virulence attenuation of food borne pathogen-Escherichia coli O157:H7Sandra Oloketuyi, Fazlurrahman Khan, 2017, pregledni znanstveni članek Opis: Enterohemorrhagic Escherichia coli (E. coli) O157:H7, a gram-negative bacteria identified as a foodborne pathogen causing severe disease is of great concern worldwide. The pathogenicity of E. coli O157:H7 is due to the presence of some virulence factors and its ability to form biofilm which resist antimicrobial compounds, withstand harsh environmental condition and protects from the host immune responses. Formation of biofilm is a multistep process such as adhesion, cellular aggregation and productions of extracellular matrix in which colonies are embedded. There are high numbers of research in the discovery of natural and synthetic compounds which can attenuate the E. coli O157:H7 biofilm formation as well as suppress virulence-related genes. The present review article focuses on the steps involved in E. coli O157:H7 biofilm formation, factors associated with virulence and attenuation. Ključne besede: Escherichia coli, pathogen, virulence Objavljeno v RUNG: 14.01.2021; Ogledov: 3130; Prenosov: 0 Gradivo ima več datotek! Več... |
8. Regulation and controlling the motility properties of Pseudomonas aeruginosaFazlurrahman Khan, Dung Thuy Nguyen Pham, Sandra Oloketuyi, Young-Mog Kim, 2020, pregledni znanstveni članek Opis: Chronic infections caused by Pseudomonas aeruginosa have been a major concern as their spread and mortality continue to be on the rise. These infections are majorly attributed to biofilm formation via sequential steps where motility plays an essential role in initial attachment of bacterial cells onto biotic and abiotic surfaces, thereby contributing to multi-drug resistance among pathogens. Therefore, attenuating motility properties can be considered as highly potential for controlling P. aeruginosa biofilm formation. This strategy has employed the use of various natural and chemically synthesized compounds. The present review article explained the importance and regulation of different types of motilities properties. Furthermore, it also covered several important alternative approaches using anti-motility agents which could be helpful for controlling P. aeruginosa biofilm-associated infections. Further studies are required for in-depth understandings about the mechanisms of motilities controlling of these molecules at molecular levels. Ključne besede: Biofilm, Motility, Attenuation, Antibiofilm drugs, Pseudomonas aeruginosa Objavljeno v RUNG: 12.01.2021; Ogledov: 3553; Prenosov: 0 Gradivo ima več datotek! Več... |