Under the protection of biofilm, microbial cells in biofilm become tolerant and resistant to antibiotics and the immune responses, which increases the difficulties for the clinical treatment of biofilm infections.
What can biofilms teach us about infectious disease?
The important hallmarks of chronic biofilm-based infections are extreme resistance to antibiotics and many other conventional antimicrobial agents, and an …
What are the features of biofilm development?
Characteristics of biofilms that can be important in infectious disease processes include a) detachment of cells or biofilm aggregates may result in bloodstream or urinary tract infections or in the production of emboli, b) cells may exchange resistance plasmids within biofilms, c) cells in biofilms have dramatically reduced susceptibility to antimicrobial agents, d) biofilm …
Do we need diagnostic criteria for biofilm infections?
· Bacteria within biofilms are intrinsically more resistant to antimicrobial agents than planktonic cells because of the diminished rates of mass transport of antimicrobial molecules to the biofilm associated cells or because biofilm cells differ physiologically from planktonic cells . Antimicrobial concentrations sufficient to inactivate planktonic organisms are …
Does biofilm contribute to the intensity of inflammation?
· Antimicrobial drug resistance is 1 of the hallmark characteristics of microbial biofilms. Microbial cells associated with matured biofilms can be as much as 1000-fold more tolerant/resistant to antimicrobial drug therapy than their planktonic cell counterparts.
How can biofilms complicate treatment of infectious diseases?
Under the protection of biofilm, microbial cells in biofilm become tolerant and resistant to antibiotics and the immune responses, which increases the difficulties for the clinical treatment of biofilm infections.
What about biofilms makes them difficult to treat using antibiotics?
Biofilm is a complex structure of microbiome having different bacterial colonies or single type of cells in a group; adhere to the surface. These cells are embedded in extracellular polymeric substances, a matrix which is generally composed of eDNA, proteins and polysaccharides, showed high resistance to antibiotics.
Why are biofilms problematic in disease treatment?
Biofilms pose a serious problem for public health because of the increased resistance of biofilm-associated organisms to antimicrobial agents and the potential for these organisms to cause infections in patients with indwelling medical devices.
What are the disadvantages of biofilms?
The major disadvantage of biofilms include, high corrosivity, and lack of machine stability. Biodispersants are designed to ensure that microorganisms are dispersed into the process water. They are effective in performing a function using a multiple of mechanisms, and are treated as a substitute to a biocide.
Why does a biofilm make it harder to eradicate a bacterial infection?
They are hard to eradicate because they secrete a matrix made of sugar molecules which form a kind of armour that acts as a physical and chemical barrier, preventing antibiotics from reaching their target sites within microbes.
Why are biofilms resistant to antibiotics and disinfectants?
The antibiotic resistance is supported due to the transition of the colony from exponential to slow or without growth/persisters phenomena. The Glycocalyx matrix through the efflux system and enzymes, inactivate antimicrobial agents and protect the peripheral region of the biofilm.
Why does biofilm increase the risk of infection?
In addition to the protection offered by the matrix, bacteria in biofilms can employ several survival strategies to evade the host defense systems. By staying dormant and hidden from the immune system, they may cause local tissue damage and later cause an acute infection.
Why are biofilms of concern to medicine quizlet?
Biofilms are commonly found on surfaces in nature and in the human body, where they may be beneficial or cause severe infections. Pathogens associated with biofilms are often more resistant to antibiotics and disinfectants.
How does a biofilm protective barrier make it resistant to antibiotics?
By forming a biofilm, bacteria protect themselves from host defense, disinfectants, and antibiotics. Bacteria inside biofilm are much more resistant to antimicrobial agents than planktonic forms since bacteria that are unresisting to antimicrobial agents in any way can turn resistant after forming a biofilm.
What is a biofilm that is detrimental to human health?
Dental plaque is a common example of a biofilm that forms on tooth surfaces. The products of metabolism of the bacteria in plaque are responsible for tooth decay and gum disease. Biofilms can harbor human infectious agents in the environment, but they also can promote remediation of contaminated groundwater and soils.
Is biofilm deleterious to health?
Yes, we can house dangerous slimes called biofilms in our bodies. They can cause severe infections anywhere in our bodies. They contain bacteria hidden and hibernating in a protective matrix. This makes them really difficult to treat.
Are biofilms all that harmful?
The truth is that all biofilms are not bad. We can even look to nature to provide fine examples of biofilms, such as fuel cells and marine engineering systems. Recently however, there has been a lot of attention on biofilm formation on contact lenses and lens storage cases.
What is the role of biofilms in microbiology?
Research should also focus on the role of biofilms in antimicrobial resistance, biofilms as a reservoir for pathogenic organisms , and the role of biofilms in chronic diseases. The field of microbiology has come to accept the universality of the biofilm phenotype.
What is a biofilm?
A Historical Basis. A biofilm is an assemblage of surface-associated microbial cells that is enclosed in an extracellular polymeric substance matrix. Van Leeuwenhoek, using his simple microscopes, first observed microorganisms on tooth surfaces and can be credited with the discovery of microbial biofilms.
What is attachment in biology?
Attachment is a complex process regulated by diverse characteristics of the growth medium, substratum, and cell surface. An established biofilm structure comprises microbial cells and EPS, has a defined architecture, and provides an optimal environment for the exchange of genetic material between cells.
What is the interface between a surface and an aqueous medium?
The solid-liquid interface between a surface and an aqueous medium (e.g., water, blood) provides an ideal environment for the attachment and growth of microorganisms. A clear picture of attachment cannot be obtained without considering the effects of the substratum, conditioning films forming on the substratum, hydrodynamics of the aqueous medium, characteristics of the medium, and various properties of the cell surface. Each of these factors will be considered in detail.
What are the characteristics of aqueous medium?
Other characteristics of the aqueous medium, such as pH, nutrient levels, ionic strength, and temperature, may play a role in the rate of microbial attachment to a substratum. Several studies have shown a seasonal effect on bacterial attachment and biofilm formation in different aqueous systems ( 17, 18 ). This effect may be due to water temperature or to other unmeasured, seasonally affected parameters. Fletcher ( 19, 20) found that an increase in the concentration of several cations (sodium, calcium, lanthanum, ferric iron) affected the attachment of Pseudomonas fluorescens to glass surfaces, presumably by reducing the repulsive forces between the negatively charged bacterial cells and the glass surfaces. Cowan et al. ( 21) showed in a laboratory study that an increase in nutrient concentration correlated with an increase in the number of attached bacterial cells.
Do bacteria have hydrophobic surfaces?
Most bacteria are negatively charged but still contain hydrophobic surface components, as noted by Rosenberg and Kjelleberg ( 22 ). Fimbriae, i.e., nonflagellar appendages other than those involved in transfer of viral or bacterial nucleic acids (called pili), contribute to cell surface hydrophobicity.
What are the functions of fimbriae?
Fimbriae play a role in cell surface hydrophobicity and attachment, probably by overcoming the initial electrostatic repulsion barrier that exists between the cell and substratum ( 23 ).
How does biofilm develop?
When an indwelling medical device is contaminated with microorganisms , several variables determine whether a biofilm develops. First the microorganisms must adhere to the exposed surfaces of the device long enough to become irreversibly attached. The rate of cell attachment depends on the number and types of cells in the liquid to which the device is exposed, the flow rate of liquid through the device, and the physicochemical characteristics of the surface. Components in the liquid may alter the surface properties and also affect rate of attachment. Once these cells irreversibly attach and produce extracellular polysaccharides to develop a biofilm, rate of growth is influenced by flow rate, nutrient composition of the medium, antimicrobial-drug concentration, and ambient temperature. These factors can be illustrated by examining what is known about biofilms on three types of indwelling medical devices: central venous catheters, mechanical heart valves, and urinary (Foley) catheters.
What organisms are in a urinary catheter?
The organisms commonly contaminating these devices and developing biofilms are S . epidermidis, Enterococcus faecalis, E. coli, Proteus mirabilis, P. aeruginosa, K. pneumoniae, and other gram-negative organisms ( 1 ). The longer the urinary catheter remains in place, the greater the tendency of these organisms to develop biofilms and result in urinary tract infections. For example, 10% to 50% of patients undergoing short-term urinary catheterization (7 days) but virtually all patients undergoing long-term catheterization (>28 days) become infected ( 1 ). Brisset et al. ( 26) found that adhesion to catheter materials was dependent on the hydrophobicity of both the organisms and the surfaces; catheters displaying both hydrophobic and hydrophilic regions allowed colonization of the widest variety of organisms. Divalent cations (calcium and magnesium) and increase in urinary pH and ionic strength all resulted in an increase in bacterial attachment. Tunney et al. ( 27) stated that no single material is more effective in preventing colonization, including silicone, polyurethane, composite biomaterials, or hydrogel-coated materials. Certain component organisms of these biofilms produce urease, which hydrolyzes the urea in the patient's urine to ammonium hydroxide. The elevated pH that results at the biofilm-urine interface results in precipitation of minerals such as struvite and hydroxyapatite. These mineral-containing biofilms form encrustations that may completely block the inner lumen of the catheter ( 27 ). Bacteria may ascend the inner lumen into the patient's bladder in 1 to 3 days ( 28 ); this rate may be influenced by the presence of swarming organisms such as Proteus spp. (D. Stickler, pers. comm.). Several strategies have been attempted to control urinary catheter biofilms: antimicrobial ointments and lubricants, bladder instillation or irrigation, antimicrobial agents in collection bags, impregnation of the catheter with antimicrobial agents such as silver oxide, or use of systemic antibiotics ( 29 ). Most such strategies have been ineffective, although silver-impregnated catheters delayed onset of bacteriuria for up to 4 days. In a rabbit model, biofilms on Foley catheter surfaces were highly resistant to high levels of amdinocillin, a beta-lactam antibiotic ( 30 ). However, Stickler et al. ( 31) found that treatment of a patient with a polymicrobial biofilm-infected catheter with ciprofloxacin allowed the catheter to clear and provide uninterrupted drainage for 10 weeks. Morris et al. ( 32) found that time to blockage of catheters in a laboratory model system was shortest for hydrogel- or silver-coated latex catheters and longest for an Eschmann Folatex S All Silicone catheter (Portex Ltd., Hythe, Kent, England). Biofilms of several gram-negative organisms were reduced by exposure to mandelic acid plus lactic acid ( 33 ). In a study in which ciprofloxacin-containing liposomes were coated onto a hydrogel-containing Foley catheter and exposed in a rabbit model, the time to development of bacteriuria was double that with untreated catheters, although infection ultimately occurred in the rabbits with treated catheters ( 34 ).
How does biofilm affect the immune system?
The effects of biofilms are seen primarily in 4 ways by facilitating the emergence of antimicrobial drug resistance, generating chronic infections, the modulation of host immune response, and the contamination of medical devices. The biofilm lifestyle also enhances the survival of microorganisms in adverse environmental conditions.
Why are biofilms important?
Medical Importance of Microbial Biofilms in the Management of Infectious Diseases . Biofilms are an emerging clinical problem despite the fact that most clinicians don’t even think of biofilms when managing infections. Microbial biofilms are associated with and impact the management of over 75% of all infections.
What is microbial biofilm?
Microbial biofilm is also a well-known modulator of the host immune response towards invading pathogens. Normally, the inflammatory response mounted by the host is directed against infectious microorganisms and is intended to protect the host cells and destroy the invading pathogen (s). In contrast, there are several clinical situations involving chronic infections where the proinflammatory immune response against the pathogen (s) is more harmful than helpful to the host cells. In most cases, the presence of microbial biofilm is the underlying cause for the misdirected attack. 7,8
Is biofilm a virulence factor?
In essence, biofilms are a poorly understood virulence factor. They are an emerging clinical problem, despite the fact that most clinicians don’t even think of biofilms when managing infections. In fact, clinicians base many decisions on planktonic in vitro susceptibilities instead of sessile or biofilm susceptibilities.
How long do chronic infections last?
In contrast, chronic infections may persist for prolonged periods of time, occasionally for months or even years.
Why is biofilm important?
Biofilm formation is a critical issue for almost all surfaces in health care and food preparation settings. Biofilms can grow on medical implants, creating the opportunity for infections to flourish and even facilitate human deaths, for these tough microbial communities can resist antibiotics and evade the immune system.
How does biofilm work?
The biofilm operates more like a multicellular organism than a collection of organisms, increasing the odds of survival among “community” members. Bacterial colonies even communicate among themselves by a primitive system of chemical signals. Any bacterium can form a biofilm once it finds a place to stick.
What are biofilms in the mouth?
In fact, the human body has biofilms in the mouth and intestinal track that can protect our health or harm it. Dental plaque is a common example of a biofilm that forms on tooth surfaces. The products of metabolism of the bacteria in plaque are responsible for tooth decay and gum disease.
What is a biofilm?
Dental plaque is a common example of a biofilm that forms on tooth surfaces. The products of metabolism of the bacteria in plaque are responsible for tooth decay and gum disease. Biofilms can harbor human infectious agents in the environment, but they also can promote remediation of contaminated groundwater and soils.
What is the shift in microbiology?
A 1996 review article in the journal Science reported on an important shift in understanding in microbiology: that bacteria, instead of floating freely, commonly aggregate as clumps surrounded by slime and stuck to surfaces. If not disrupted, these biofilms thrive under the right conditions.
Can bacteria form biofilm?
Any bacterium can form a biofilm once it finds a place to stick. According to the Science review article, “Slamming up against a hard surface sets off a genetic cascade that turns on specific genes to make polysaccharides and other substances needed to establish the biofilm colony.
What is biofouling in water?
Known as “biofouling,” the microbial growth represents a contamination that may present a threat to public health. As noted above, biofilms can harbor human pathogens that are difficult to kill. Chlorinating the water supply is the usual method employed to control biofilm growth.
What is biofilm disease?
Biofilm disease includes device-related infections, chronic infections in the absence of a foreign body, and even malfunction of medical devices. Areas covered: This review puts forward a new medical entity that represents a major public health issue, which we have named 'biofilm-related disease'. We highlight the characteristics ...
What is biofilm formation?
Biofilm formation represents a protected mode of growth that renders bacterial cells less susceptible to antimicrobials and to killing by host immune effector mechanisms and so enables the pathogens to survive in hostile environments and also to disperse and colonize new niches.