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Phytomedicines Targeting Antibiotic Resistance through Quorum Sensing and Biofilm Formation Associated with Acne Vulgaris
Published in Namrita Lall, Medicinal Plants for Cosmetics, Health and Diseases, 2022
Isa A. Lambrechts, Namrita Lall
In nature, most microorganisms do not exist as planktonic bacteria floating in a suspension but rather as a biofilm. Biofilms form when populations or communities of bacteria arrange in layers, together with their decomposition and metabolic products, and adhere to abiotic and biotic surfaces such as the wall of the pilosebaceous unit. After the bacteria have adhered to surfaces, they start to secrete polysaccharides in which these bacteria are encased. The extracellular polysaccharide is around 70% of the biofilm mass and is essential for biofilm architecture. The biofilm is comprised of four components: water, extracellular DNA (eDNA), extracellular polysaccharides and cellular byproducts. Extracellular DNA is produced due to quorum sensing and plays a role in biofilm formation, gene transfer, biofilm stabilization and bacterial and biofilm attachment to a stratum. The extracellular polysaccharide is a glycocalyx polymer, which functions as a protective layer that prevents effective concentrations of antimicrobials from entering the microenvironment of the bacteria. Compared to planktonic bacteria, bacteria associated with a biofilm have altered growth and gene expression. It has been found that bacteria inside the biofilm is more resistant to antibiotics (50–500 times more) than planktonic bacteria not associated with a biofilm (Montanaro et al., 2011; Burkhart and Burkhart, 2003; Sandasi et al., 2011; Yarwood and Schlievert, 2003).
The diagnosis and management of preterm labor with intact membranes
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Roberto Romero, Tinnakorn Chaiworapongsa, Francesca Gotsch, Lami Yeo, Ichchha Madan, Sonia S. Hassan
The clinical significance of this relates to the challenges encountered with diagnosis and treatment of this condition. First, the diagnosis of microbial invasion in the presence of biofilms is extremely challenging, and current cultivation techniques are inadequate to detect such infections. The consequences are that the frequency of infection of the amniotic cavity may be underestimated and that molecular microbiologic techniques will be required to improve diagnosis. Second, the optimal treatment of biofilm-related infections represents a challenge in clinical medicine. Antimicrobial agents appear to be inactivated or fail to reach bacteria within a biofilm. Interestingly, bacteria within biofilms have increased resistance to antimicrobial compounds even though the same bacteria can be sensitive to the same agent if grown under standard conditions (428–431). Thus, the difficulties in treating intra-amniotic infection may be due to the refractoriness of biofilms to conventional antibiotic treatment. Third, biofilms in the amniotic fluid may represent a unique form of these structures, which can be dislodged by fetal movement, resulting in seeding of planktonic bacteria and the eliciting of an inflammatory response.
Hazard Analysis and Critical Control Point (HACCP) Protocols in Cosmetic Microbiology
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Laura M. Clemens, Harry L. Schubert
CIP systems can very quickly become inoculation sources rather than means of effective cleaning and sanitization. For this reason, the design and management of these systems can be even more critical than the process systems they support. Inoculation occurs because production systems often remain idle between uses and the last fluid contained is typically purified water. Because such systems are non-drainable and present the risk of building biofilms, they can become ideal sources of organisms adapted to the cleaning and sanitizing media and also to product preservative systems. These biofilms aid the development of resistance to cleaning agents and continue to build protective shields into the process systems they are intended to clean.
A novel microplate-based spectrophotometric method for the quantitative assessment of freshwater bacterial coaggregation kinetics
Published in Biofouling, 2023
M.A.L. Hayashi, K. Narender Singh, J.T.F. Wing, A.H. Rickard
Coaggregation is the specific recognition and adhesion between genetically distinct bacteria (Whittaker et al. 1996). While originally detected between human oral bacteria, it has since been shown to occur between microorganisms from a wide range of environments including freshwater biofilms, activated sludge, human skin, and the human urogenital tract (Reid et al. 1988; Rickard et al. 2002; Malik et al. 2003; Kumar et al. 2019). Evidence of freshwater bacterial coaggregation was first presented 25 years ago (Buswell et al. 1997). Cumulative evidence from different research groups has since indicated that coaggregation occurs between numerous freshwater bacterial species (Rickard et al. 2002; Simões et al. 2008; Vornhagen et al. 2013; Cheng et al. 2014) and is mediated by highly specific complementary adhesin-receptor interactions (Rickard et al. 2000; Simões et al. 2008). In addition, two studies from two independent research groups have indicated that under in vitro conditions, coaggregation between freshwater bacteria enhanced biofilm development (Simões et al. 2008; Min and Rickard 2009). Freshwater biofilms are of concern as they can aid in the retention and enrichment of pathogens (Wang et al. 2021; Hayward et al. 2022), increase the bacterial load in the surrounding water (Liu et al. 2013; Douterelo et al. 2014), promote microbial induced corrosion (Yang et al. 2012), and reduce the chemical and cosmetic quality of water (Kerr et al. 2003; Zhou et al. 2017).
Candida auris biofilm: a review on model to mechanism conservation
Published in Expert Review of Anti-infective Therapy, 2023
Arsha Khari, Biswambhar Biswas, Garima Gangwar, Anil Thakur, Rekha Puria
Biofilm-associated infections are a major public health concern because the microenvironment can decrease the adequacy and susceptibility of antifungal agents while also evading the host’s immune response. As a result, the formation of biofilms has been widely researched. The success depends on the accurate prediction of the pathology of C. auris infection which requires the development of models that closely mimics the conditions prevalent during pathogenesis. To study the effect of various environmental conditions or small molecule inhibitors or the role of genes in the pathobiology of biofilm several in vitro techniques are used to assess biofilm development in C. auris. Studies of the growth sensitivity and/or resistance of C. auris biofilms to antifungal agents frequently include various colourimetric tests or microtitre plate assays such as XTT, and MTT assays. Additionally, confocal microscopy, transmission, and scanning electron microscopes have been utilized to analyze ECM and visualize the development of biofilm cells at different stages. To understand the finer details of biofilm various ex-vivo and in-vivo models which mimic the actual conditions used by pathogens for biofilm are being developed over the years (Figure 1). Some of the established ex-vivo and in-vivo models are reviewed here.
Anti-adhesion and antibiofilm activities of Lavandula mairei humbert essential oil against Acinetobacter baumannii isolated from hospital intensive care units
Published in Biofouling, 2022
Raja El Kheloui, Asma Laktib, Soufiane Elmegdar, Lahbib Fayzi, Chorouk Zanane, Fouad Msanda, Khalil Cherifi, Hassan Latrache, Rachida Mimouni, Fatima Hamadi
Making the situation more challenging is that A. baumanni has a sophisticated survival and resistance mechanism which involves adhering to surfaces and forming biofilms (Elkheloui et al. 2022). Biofilms are a community of bacteria adhering to biotic or abiotic surfaces in a protective matrix of biopolymers (Lee Ro et al. 2017). This phenomenon begins with the adhesion of the bacteria to a suitable surface. This step can involve several factors of which the surface physicochemical properties are a major one (Zineba et al. 2014). Adhesion is followed by cell aggregation and proliferation to form biofilm microcolonies and, in order to obtain a mature biofilm, the bacterial cells produce extracellular biopolymers matrix (exopolysaccharides, proteins and extracellular DNA) (Toole et al. 2000). This biofilm forming ability allows A. baumanni to adapt and survive on various surfaces and under critical environmental conditions such as antibiotic therapy, high temperature variations, different intensities of ultraviolet and ionizing radiation in hospitals (Rampelotto 2010). Furthermore, biofilm forming bacteria can cause chronic infections, as this bacterium is recognized to be a cause of nosocomial infections, such as ventilator-associated pneumonia, bacteremia, meningitis, urinary tract and wound infections (Lee et al. 2017).