Pathogenic and Non-Pathogenic Microorganisms - Term Paper Example

Pathogenic and Non-pathogenic Microorganism Pathogenic and Non-pathogenic Microorganism Microorganisms are tiny living organism that can only be identified by use of powerful microscope. They are classified into bacteria, yeast, protozoa and algae. Microorganisms are further categorized into two based on their economic significance (Haug, et al, 2010). The first category constitutes those forms of microorganism that make vital involvement by helping to maintain the balance in ecosystem and regulating chemicals in our environment. This category of microorganism is termed as non-pathogenic microorganism. They include the soil microorganism, the marine and fresh water microorganism. They also include the gut microorganism that are found in the intestine and assist in digestion and synthesis of some vitamins such as B vitamins (Hajek &Tobin, 20110). The second category of microorganism is termed as pathogenic microorganism. These microorganisms that have potential of producing diseases. These microorganisms have specific anatomical and structural features that enable them successfully get entry into the host and hence causing diseases. They possess certain factors that enable them drive in unfavorable environment created by presence of secretory immunoglobulin A and presence of other forms of adverse conditions such as extreme temperatures and pH. These factors are termed as virulence factors. They include the structural adaptation to environmental conditions, metabolic adaptation and environmental adaptation (Hara-Kudo & Takatori, 2011). Like any other kind of organism, micro organisms exhibit the similar characteristics such as reproduction, nutrition, movement, respiration, response to stimuli and growth. Pathogenic microorganisms are capable of causing diseases in two ways. The first and common way is when the pathogenic microorganism gain access to the host and is able to adhere and damage the host tissues. Another form of pathogenic microorganism may not damage the host tissues. This form is capable of causing disease through accumulation of the waste products (Haug, et al, 2010). Principally, the pathogenic microorganism has some distinct features that distinguish them from the non-pathogenic microorganism. Research has found out that most of the pathogenic microorganisms possess distinct anatomical features that curb them from being digested by host’s enzymes. Others have distinct external attachments that help them during penetrating to the host. It has been found that most of the pathogenic microorganisms such as Shigella species possess protein called actin that helps them penetrate the host (Hara-Kudo & Takatori, 2011).. Research conducted by Haug, et al, 2010 reveals that some pathogenic microorganism such as salmonella strains and E. coli are capable of producing surface protein termed as invasin. Invasin is a protein that has potential of disrupting the plasma membrane of the host cell. Following the disruption, the microorganism can get access into the system. Furthermore, other pathogenic microorganism such as Shigella species and Listeria species have been found that they possess protein called actin that enable them move through the cytoplasm (Haug, et al, 2010). Possession of these distinct features is one of the ways in which the pathogenic microorganisms differ from the non-pathogenic microorganism. Another aspect distinguishing the pathogenic microorganism from the non-pathogenic microorganism is the fact that they have special enzymes that protect them from the phagocytosis (Hajek &Tobin, 20110). Members of the genus straphylococcus have been associated with the production of enzyme called coagulases. These enzymes protect the microorganism from phagocytosis. Other examples of enzyemes that protect the pathogenic micororganims are the kinases, hyaluronidase, collagenase, and IgA proteases. Straphylococcus aureus, for example has been associated with an enzyme called staphylokinase. Some species of Clostridia produces enzyme hyaluronidase which help them spread from initial site of infection (Hara-Kudo & Takatori, 2011). Pathogenic microorganisms also differ from the non-pathogenic microorganism in the sense that they have potential of producing toxin. This is a feature that is not found in the non-pathogenic microorganism. However, some form of microorganism such as the viruses do not produce the toxins but they are capable of multiplying in large numbers and hence killing the host cell. as far as entry into the host system is concerned, virus have attachment sites for receptors on their target cell. Fungi, on the other hand, do not have well-defined virulence factors (Hajek &Tobin, 20110). From the foregoing discussion, it is clear that the main difference between the pathogenic microorganism and non-pathogenic microorganism is that the pathogenic microorganisms have well-defined and several virulence factors. However, non-pathogenic microorganisms do not possess most of these virulence factors. Beside the virulence factors possessed by different microorganism, it is important to note that the pathogenic and non-pathogenic microorganism exhibit distinct environmental requirements. They also have specific metabolism characteristics. These characteristics are what make a certain microorganism fit into particular environment. The next section of this work shall compare and contrast the pathogenic and non-pathogenic microorganism based on a number of sub topic which include the structural and evolution of microbes, the environmental requirement for growth, and role of fulfillment in ecological cycle, benefits derived from the microbes. In particular, every section of this discussion would involve some specific pathogenic and non-pathogenic microorganism that have distinct features that offer them the ability of causing diseases (Hara-Kudo & Takatori, 2011). Structure and Evolution of Microbes Microbes have undergone a number of structural modification and evolution in order to fit into any given environment. It is clear that pathogenic microorganism have undergone several evolutionary changes as compared to the non-pathogenic microorganism. One of the reasons for this difference is the fact that as human being tries to control them by applying antimicrobial agents, some of the microorganism would develop resistance to the chemicals used and hence form mutant forms. The mutant forms can reproduce yielding new species with better adaptive mechanism to adverse environmental effects and chemicals (Davis & Bent, 2011). From structural standpoint, the pathogenic and non-pathogenic microorganism share several structural similarities. For the purpose of this paper, we shall focus on a number of pathogenic microorganisms that have distinct structural features that acts as protective mechanism. Specifically, the paper shall consider the Bacillus anthracis as the pathogenic microorganism mainly because of its distinct external cell wall which is capsulated. It would also compare the encapsulated Steptococcus pneumonia, which is a pathogenic microorganism and the unencapsulated Steptococcus pneumonia, which is non-pathogenic. However, it should be noted that different pathogenic microorganism exhibit different structural features and hence it would not be comprehensive to discuss one specific pathogenic microorganism. This is because it would result in scanty information that cannot justify the possession of sufficient knowledge. The paper would also briefly some structural features found in pathogenic microorganism such as the Treponema pallidum, a causative agent of the syphilis. This is because this is a pathogenic microorganism that posses a unique external feature called axial filament. It would also mention briefly about the Clostridium (Haug, et al, 2010). As far as the structural features are concerned, and microorganisms are categorized into prokaryotic and eukaryotic. Consequently, there are prokaryotic pathogenic microorganism and prokaryotic non-pathogenic microorganism. On the other hand, there are eukaryotic pathogenic and eukaryotic non-pathogenic microorganisms. This paper would therefore categorically analyze structural similarities and difference between each of these forms of microorganism. The paper shall start by focusing on the prokaryotic microorganism (Davis & Bent, 2011). Prokaryotic microorganism are those forms of microorganism whose DNA and other genetic materials are not enclosed within the membrane. They also lack membrane-enclosed organelles. The pathogenic and non-pathogenic prokaryotic microorganisms share a number of similarities and differences. Pathogenic and no pathogenic prokaryotic microorganism have external structures such as glycocalyx, flagella, fibriae and pilli. Glycocalyx is sticky polymer of polypeptide and polysaccharide. Glycocalyx can be viscous or can be firmly attached (Haug, et al, 2010). Pathogenic microorganisms have firm well arranged glycocalyx called capsule. On the other hand, the non-pathogenic prokaryotic microorganism lacks this kind of glycocalyx. Instead, they have viscous glycocalyx. Viscous glycocalyx is also called slimelayer. The main reason why the pathogenic microorganism have capsule instead of slime layer is that it is an adaptive mechanism through which these form of microorganism can protect themselves from phagocytosis. In other words, capsule enhances the bacterial virulence and hence making the prokaryotic pathogenic microorganism less susceptible to phagocytosis. An example of prokaryotic pathogenic microorganism is Bacillus anthracis. This bacterium is capable of synthesizing capsule from the D-glutamic acid. These prevent them from phagocytosis and this is why they are capable of causing anthrax. Other pathogenic microorganisms that are capable of producing capsule include the Steptococcus pneumonia which produce polysaccharide capsule. Generally, the pathogenic prokaryotic microorganism have capsule whereas non-pathogenic microorganism do not. This is why the unencapsulated S. pneumonia cannot cause pneumonia. Research has revealed that both the pathogenic and non-pathogenic prokaryotic microorganism have flagella in their external cell wall. Flagella are a structure that is used to facilitate movement. Flagella enable a microorganism to move toward a favorable environment. As far as external structures are concerned, the pathogenic microorganism have other special external structures that offer them means through which they can get access into the host’s cells or tissues (Hajek &Tobin, 20110). Most of the pathogenic prokaryotes have special external structures called axial filaments, fimbriae, and pili. Treponema pallidum, a causative agent of syphilis has axial filament that aids the microorganism during movement. Axial filament enable T. pallidum move effectively through body fluids. Both the pathogenic and non-pathogenic microorganism have the cell wall. The cell wall of these microorganisms is composed of a compound called peptitoglycan (Davis & Bent, 2011). There are two kinds of microorganisms as far as the cell wall is concerned. There are gram-positive and gram negative microorganism. The difference between these two forms of microorganism is based on the thickness and the structure of their cell wall. Gram positive microorganisms have thinker cell wall with several peptides cross bridges. Because of this, it is possible for such wall to absorb the stain and that is why they are called gram positive meaning that they can absorb and retain the gram’s stain. Gram positive cell wall is also vulnerable to antimicrobial agents such as penicillin because this antimicrobial agent can get access into the spaces between the peptide cross bridges and hence attacking the bridges (Hajek &Tobin, 20110). Research has found out that most of the pathogenic microorganisms are gram negative. One of the reasons why this is so is that gram negative microorganism has cell wall that does not allow the entry of antimicrobial agents. Both the pathogenic and non-pathogenic microorganism share several similarities in their internal structures. They all have plasmalemma that serves as a barrier through which materials enter and exit the cell. They also have cytoplasm, nucleoid, ribosome. However, as far as internal structures is concerned, it is important to note that most of the pathogenic microorganisms have special internal structures called endopores. Examples of such pathogenic microorganism include the genera Clostridium and Bacillus. Coxiella burnetti, a causal agent of Q-fever has an endospore that enable them resist heat and chemicals (Haug, et al, 2010). Environmental requirement for growth As stated earlier, growth is a basic characteristics for all living things including the microorganism. growth occurs when the nutrients consumed are converted into macromolecules such as such as proteins and lipids. This is achieved through metabolism is the process by which nutrients are combined together to build up complex molecules or the process by which the complex molecules are broken down to simpler molecules with the release of energy. Metabolism is mediated through enzyme catalyzed reactions. Pathogenic and non-pathogenic microorganisms share several features as far as metabolism is concerned (Hajek &Tobin, 20110). Virtually all these forms of microorganism exhibit all the basic catabolic and anabolic pathways. However, one thing that should be noted as far as the metabolism is concerned is the fact that there are aerobic and anaerobic microorganisms. Aerobic microorganisms are those forms of microorganism that requires oxygen for metabolism. Aerobic microorganisms differ from anaerobic microorganism in the sense that they utilize several pathways. It is important to note that most of the microorganisms are found in environment that possesses the main requirements like presence of nutrients, oxygen, moisture and other nutritional requirements (Hajek &Tobin, 20110) Despite the fact that pathogenic and non-pathogenic microorganism share several similarities as far as nutritional aspects are concerned, most of the pathogenic microorganism are more adaptive and can withstand wider range of environmental factors. The growth of microorganism is influenced by factors such as availability of nutrients, the nature of environmental conditions, the accumulation of waste products and even the competition(Madigan & Martinko, 2006).This is why when the growth curve of microorganism are plotted, the curve would have alternating phases of steep gradient and stationary gradient. An ideal growth curve of microorganism is shown below. Most of the pathogenic microorganism would display this kind of curve. As shown, there are different phases. Phase represented by A is called the lag phase. This is where the growth rate is insignificant. This phase takes place during the initial stages of invasion. During that time, the resistance is higher because the body is producing the enzymes that aim at destroying the microorganism. However, after some time, the microorganisms develop defensive mechanism and start growing at an exponential rate. This is represented by phase B. in this phase, the competition is minimal and the nutrients are available in plenty. This phase is followed by as stationary phase where the growth rate starts to flatten. In this phase, the death rate cancels with the growth rate. At this point, the nutrients are exhausted and the waste products start accumulating (Hajek &Tobin, 20110). This phase is followed by the last phase called the decline phase where the population of the microorganism starts declining. The conditions are not favorable in the sense that the waste products have accumulated to the toxic levels. The amount of nutrients is also scarce and the competition is extremely high. According to the available findings, the pathogenic microorganisms mainly exhibit this kind of curve. This curve is not common in non-pathogenic microorganism in the sense that they normally coexist with the host symbiotically (Davis & Bent, 2011). Having understood how the growth rates behaves, the next section shall focus on how certain environmental factors influence the growth and survival of pathogenic and non-pathogenic microorganism. Specifically, we shall focus on Clostridium perfringens as the pathogenic microorganism. It would then compare this with the gut micro flora. Clostridium perfringens is the ideal microorganism for this section because it can withstand wide range of temperatures (Hajek &Tobin, 20110). Microorganism carries out anabolic and catabolic metabolism. It has been found those pathogenic microorganisms are capable of metabolizing food substrates under extreme conditions. This means that their enzymes can function under extreme condition such as extreme temperatures and pH. This offers these microorganisms a protective mechanism. It makes them withstand most of the sterilization methods (Haug, et al, 2010). On the other hand, the no-pathogenic microorganism normally operates at room temperatures and can easily be killed by provision of extreme conditions. Nevertheless, there are no major distinct differences between the pathogenic and non-pathogenic microorganism as far as metabolism is concerned. However, what is more apparent as far as the difference between the pathogenic and non-pathogenic microorganism is concerned is that these two classes exhibit distinct environmental requirement for growth. As far as environmental requirements are concerned, microorganism can be classified based on the physical environmental requirements such as temperatures, pH, and osmotic pressure. The environment can also be based on the chemical requirement where we focus on aspects such as utilization of elements such as carbon, nitrogen, sulfur, and phosphorous, oxygen. It is clear that the pathogenic microorganism possesses distinct physical requirement for growth that enable them resist sterilizing agents so that they can get access to the host system (Davis & Bent, 2011). Based on temperature, there are those microorganism that dwell in cold environment, there are also those who breed well in moderate temperatures and the last category involve those that resist high temperatures. As far as temperatures are concerned, it is apparent that both pathogenic and non-pathogenic microorganism survives optimally at 370c. Nevertheless, most of the pathogenic microorganism such as Clostridium perfringens can resist high temperatures. (DeLong & Pace, 2001). Consequently, the milk products are normally heated to temperatures around 1210c so that the Clostridium perfringens are eradicated. Based on the oxygen utilization, microorganism can be classified as obligate aerobes, facultative aerobes, obligate anaerobes and aerotolerant microbes. These features of microorganism are present in both the pathogenic and non-pathogenic microorganism (Hara-Kudo & Takatori, 2011). Role of Fulfillment in Ecological Niche Different microorganism have different ecological niche. Ecological niche is an environment where the probability of finding a given microorganism is high. It should be noted that microorganisms are not independent. They coexist with other microorganism, with multi-cellular animals such as man and animals. They also interact with the physical world. These interactions give rise t fascinating associations (Madigan & Martinko, 2006). The interaction between microorganism can be beneficial, harmful and in some cases, it may yield no particulate change to man. Some microorganisms have a symbiotic ecological niche. This is where the microorganism live together or in partnership with other organism. Such relationship occurs if one of the members wants to benefit from the other nutritionally. Symbiotic relationship can be further classified into mutualism, commensalism and parasitism. Mutualism is a form of relation when microorganisms live in an obligatory but mutually beneficial relationship. Most of the non-pathogenic microorganism expresses this form of relation. A good examples are those microorganism found in the digestive tract. These microorganisms rely on the food eaten by the host but at the end, every party would have benefit. Commensalism is another form of symbiotic relationship. However, in this kind of relationship, one of the member benefit while the coinhabitant is not harm. This kind of relationship is also common among the non-pathogenic microorganism. Parasitism is the last form of symbiotic relationship whereby the host organism provides the nutrient and habitat for the microbe. However, as the microorganism increases in number, they start harming the host (Hara-Kudo & Takatori, 2011). This kind of ecological association is also common among the pathogenic microorganism. It is apparent that the human body is a major reservoir for symbiotic bacteria, fungi and few protozoa. This means that most of them express either the parasitic, commensal and synergistic relationship with their host. It has been found that Escherichia coli, which live in the intestine produces vitamin K (DeLong & Pace, 2001). The body, would utilize the vitamin K and on the other hand the E. coli would rely of the food taken by the host for its survival. Another nonpathogenic microorganism that displays symbiotic relationship is Lactobacillus. These microorganisms reside in the vagina. They have a role of maintaining an acidic environment. This environment would protect the vagina against infections by other microorganism (Hara-Kudo & Takatori, 2011). From the foregoing discussion, it is apparent that the different microorganisms have different roles to play in various ecological niches. Non-pathogenic microorganism has a beneficial role to play as far as it is their ecological niche is concerned. Human and animal intestines constitute the common ecological niche for most of the pathogenic microorganism. Salmonella spp. For example must get access to the intestinal columnar epithelial cells. In order for this microorganism to colonize the intestine, it must successfully compete with the indigenous gut microflora. This competition would allow the Salmonella spp. to get place where they can attach themselves to. In normal situation, the intestinal columnar epithelial cells are colonize by the beneficial gut microflora. This means that for Salmonella spp. to colonize the place and cause infection, it must successfully compete the gut microflora. Another obstacle that the Salmonella spp. has as far as fulfilling the ecological niche is that the microorganism must evade the capture by secretory immunoglobulin A. this substance is produced in the surface of the epithelial cells. Trough the external attachment, the Salmonella spp. must interact with the host glycoprotein receptors located in the microvilli of the intestinal surface (Madigan & Martinko, 2006). Benefits derived from microorganism Although most people tend to associate microorganism with infections, most of the microorganism plays a significant role in human life. It should be noted that most of the beneficial microorganism are non-pathogenic. This means that this discussion shall focus mainly on non-pathogenic microorganism. The first role is that microorganism help in maintaining the balance of living organism. They also aid in maintaining chemicals in our environment. In this vein, microorganism acts as agents through which the ecological cycle is completed. some microorganism are useful in farming sector in that they improve the soil fertility by decomposing the organic matter as well as by breaking down the waste to release nutrient in a manner that is available for plant use (Madigan & Martinko, 2006). Nitrogen fixing bacteria assist in conversion of the atmospheric nitrogen into a form that can be incorporated by plants. Soil microorganisms assist in recycling chemical elements. As mentioned earlier, there are those groups of microorganism that are mainly confined to the intestine. These forms of microorganism assist in digestion and the synthesis of some vitamins that the body requires, example of these vitamins include the B vitamins which are mainly used during metabolism. Another vitamin produce by these microorganism is vitamin K. vitamin K is used during blood clotting (Madigan & Martinko, 2006). There are also specific microorganisms that are used for commercial application. They are used to produce chemical products such as vitamins, organic acids, enzymes and alcohol. Another sector that involves the use of microorganism is the food industry. Different food product requires the use of certain microorganism. Yoghurt, bread, cheese and alcoholic beverages all requires specific strain of microorganism. Conclusion from the foregoing discussion, it is clear that though the pathogenic and nor pathogenic microorganism share the basic features of living things such as reproduction, movement, excretion, response to stimuli, nutrition and growth, pathogenic microorganism have relatively well defined features that enable them resist most of the antimicrobial agents as well as enzymatic attack (Davis & Bent, 2011). References Hajek, A. E. & Tobin, P. C. (20110. Introduced pathogens follow the invasion front of a spreading alien host. The Journal of Animal Ecology [J Anim Ecol]. 80 (6), pp. 1217-26. Davis S. & Bent S. J. (2011). Loop analysis for pathogens: niche partitioning in the transmission graph for pathogens of the North American tick Ixodes scapularis., Journal Of Theoretical Biology [J Theor Biol], 269 (1), pp. 96-103. Haug, S., Lakew, T., Habtemariam, G., Alemayehu, W.& Cevallos, V. (2010). The decline of pneumococcal resistance after cessation of mass antibiotic distribution for trachoma. Clin Infect Dis 2010;51:571-4. Hara-Kudo Y, Takatori K. (2011).Contamination level and ingestion dose of foodborne pathogens associated with infections. Epidemiology And Infection [Epidemiol Infect] (10). Madigan, M. & Martinko, J. (2006). Brock Biology of Microorganisms (13ed.). New York, NY; Pearson Education publishers. DeLong E., Pace, N. (2001). Environmental diversity of bacteria and archaea. Syst Biol 50 (4): 470–8 Read More