Biofilm (Term Paper Sample)

Biofilm
Name
Institution
Biofilm
Introduction
A Biofilm is a collection of the microbial cells that is permanently associated with a surface and it is usually embedded in a matrix mostly of polysaccharide material. Biofilm consist of basically microbial cells and extracellular polymeric substance (EPS). Non-cellular substances such as corrosion particles, clay, silt particles, blood components, or mineral crystals can exist in the biofilm matrix dependance on the setting that the matrix has formed. Formation of Biofilms can occur on a number of surfaces such as medical equipments, water-piping systems, natural aquatic systems, and even in living tissues (Donlan, 2002, p.881). Biofilms, especially on water systems can be complex while others like those on medical equipments may be simple comprising of singular coccoid or rod-shaped microorganisms. Biofilms have been found to be accountable for chronic bacterial infection, corrosion of water piping system and reducing water quality, and food contamination.
Biofilms Formation
The development of a Biofilm starts with the attachment of freely floating microbes to a surface. Under the natural environment, microorganisms do not adhere straightforwardly to a substratum as such but instead adhere to the conditioning film that forms on most substrata. The solid-liquid edge between a surface and aqueous medium becomes conditioned or covered with polymers from the medium offering a perfect environment for the attachment and development of microorganisms (Kolari, 2003, p.11). The way the surface is modified influences the pace and level of microbial attachment. According to researchers, microbes attach at a higher rate on hydrophobic resources such as Teflon and plastics than in hydrophilic substrata such as those of glass or metals.
The physical chemical content of the aqueous medium such as the PH, level of nutrients, ionic strengths, and warmth can contribute to the rate of microbes’ attachment to the surface. The microbial attachment and biofilm formation in various aqueous systems is affected by seasonal changes. It is found that increased concentration of various cations such as sodium, calcium, lanthanum, and ferric ions influences attachment of Pseudomonas fluorescence to glass by minimizing the repulsive forces between the cells and glass surfaces . (Sutherland, 2001, p.4). Cell shell hydrophobicity, existence of fimbriae, flagella, and creation of EPS also affects the rate and degree of attachment of microbes. Hydrophobicity of cell surface is significant in bonding because hydrophobic relations tend to rise with a rising non-polar nature of one or both surfaces involved.
Adhesion consists of two phases that include reversible and irreversible processes. Reversible adhesion is the first phase of microbial attachment and involves weak bonds between the cells and the surface. Irreversible or permanent bonding follows the initial phase. Bacteria influence this process via the expression of particular bacterial adhesins that binds to receptors on the surface and in the extracellular polymeric matrix. The Bacterial bonding is seen to be related to the distance between the microorganism and the substratum (Percival et al, 2011, p. 50).
Body
Biofilms comprises mostly the micro colonies of various species of microbial cells and EPS. The EPS accounts between 50% and 90% of the total organic carbon of biofilms and can be said to be the main matrix material of biofilm (Kokare et al, 2009, p. 159). EPS differs in chemical and physical composition but mainly it is made up of polysaccharides with some being neutral or polyanionic. Existence of uronic acids or ketal linked pyruvate presents the anionic characteristics. These traits are useful in associating divalent cations like as calcium and magnesium that links with the polymer threads giving a more binding force on a grown biofilm . (Sutherland, 2001, p.3). The amount of EPS produced by various organisms may differ and the quantity of EPS increases as the biofilm matures.
EPS is extremely hydrated as it can integrate large quantity of water into its formation through hydrogen bonding. EPS may correlate with metal ions, divalent cations, and other macromolecules. The amount of EPS produced is predisposed by the status of nutrients of the development medium. Excessive carbon and limited nitrogen, potassium, or phosphate enhances production of EPS. sluggish bacterial development enhances EPS creation.
Dispersal
Dispersal of cells from the biofilm colonization is an important phase in the biofilm life cycle. This phase facilitates spread of biofilms and colonization of new surfaces. Biofilm cells can be dispersed through shedding of offspring cells from dynamically growing cells, detachment due to nutrient levels, or shearing of biofilms aggregates because of flow causes. The major processes of detaching are through erosion, sloughing, and abrasion (Percival et al, 2011, p. 56). The rate of erosion is dependent on the width of biofilm – erosion is higher when biofilm is thicker.
Biofilms with a higher detachment rates contains a large fraction of active bacteria. It can also occur due to low nutrient circumstances showing that it is a survival mechanism and may be genetically determined. Thus, detachment is not just crucial for genetic diversity promotion, but also for evading unfavorable environment helping in the growth of new niches. The type of dispersal actually has an consequence on the phenotypic properties of the organism. Worn aggregates have a high prospect of retaining particular biofilm such as antimicrobial resistance properties.
Properties
Biofilms are enormously heterogeneous. In naturally occurring biofilms there is a big number of various types of microorganisms such as bacteria, protozoa fungi, and algae that live together. Furthermore, various biofilms have different internal structure with different chemical traits, varying electrical properties (Donlan, 2002, p.888). Each of these distinct traits leads to the overall varying properties of biofilms making them different. The genetic behavior of biofilm microorganism is different in comparison to their planktonic counterparts. Planktonic microbes are more prone to antimicrobial compounds developed to destroy them than biofilm bacteria. Biofilm cell can communicate and harmonize their behavior through intercellular communication by the use of biochemical signaling molecules. The chemical signs are transmitted via the external membranes and can be understood by other microbial species that are members of the biofilm.
Extracellular matrix
The microbes in a biofilm produce a kind of a matrix of hydrated extracellular polymeric substance (EPS) where they live in as their direct location. EPS composes mainly polysaccharides, proteins, nucleic acids, and lipids. EPS gives the mechanical firmness of biofilms, mediation of bonding to substratum and formation of a cohesive, three dimensional polymer network that joins and rapidly immobilization of microbial cells. The matrix also operates as an outer digestive system by maintaining extracellular enzymes near to the cells. The matrix gives protection to the cells enclosed and eases communication amongst the cells through biochemical signaling. The matrix is stronger and in some situations, the biofilm can be fossilized.
Biofilms and infectious disease
Biofilms were traditionally regarded as environmental phenomena but now they are considerably playing a big role and contributing to human infection. Biofilms have been found to form on abiotic surfaces such as the intravascular catheters, urinary catheters, and prosthetic implantations. These biofilms are formed from derivation from the skin of patients or medical personnel through inserting devices or implantation (Hung & Henderson, 2009, p. 294). Because these medical equipments mostly reside for an extended period, biofilm formations can lead to regional infections.
Insertion of Mechanical heart valves contributes to the damaging of tissue that leads to the accumulation of platelets and fibrins. The damaged tissues influence microorganism colonization to these areas and eventually formation of a biofilm in the heart tissue. It has also been discovered that biofilms can damage coetaneous wound therapeutic and reduction of topical antibacterial effectiveness in treatment of infected skin wounds.
Because of the complex structure of biofilms due to semi permanent polymeric matrix, penetration of antibiotic may be reduced. Furthermore, the minimized rate of growth and distorted physiological state of microbial cells in biofilms can make them to be more tolerant to antibiotics. In dealing with biofilms formation in implanted devices and prevention of device linked infections, effectual preventive and curative ways must be enhanced. One way is to develop these devices using anti adhesion materials such as heparin.