Importance Of Staphylococcus Aureus To Humans Biology Essay

Importance Of staph Aureus To Humans Biology EssayThe bacterial genus to be isolated and identification in this project is staph. This genus has been chosen for the antecedent of its copiousness on the scratch of mammals and the pathogenic nature of one of its member, staphylococcus aureus. Apart from skin infections, staphylococci aureus could mutate to Methicillin-resistant staphylococcus aureus (MRSA). In just about(prenominal) cases, these give rise to medical implications. In addition, the distinctive features of staphylococcus aureus from former(a) species in the genus allow it to be easily isolated and identified via culturing and bio chemical tests. staphylococcus was first discovered in 1880 by Alexander Ogston (Paniker 2005, p.192). Currently, to a greater extent than 30 different species of the genus has been identified (Deurenberg Stobberingh 2008). The name staph was derived from Greek, with the prefix Staphylo referring to bunches of grapes and the affix c occus referring to granule (Ryan Ray 2004). As the meanings suggest, bacteria from staphylococcus are circular-shaped and their emplacement resembles bunches of grapes when observed under a microscope. Typically, a staphylococci has a diam of approximately 1m (Willey, Sherwood Woolverton 2011, p.562).The aim of the project is to isolate staph aureus from the genus from a bundle of cat vibrissas and verify its identity via microscopic examination. No human specimen is used due to the potential pathogenic dimension of staph. It is intended that a pure culture of pathogenic staphylococci aureus is obtained. For the purposes of this project, the grandness of staphylococci aureus to humans, its variety in terms of morphology, physiology and social organization, methods of isolation and identification by biochemical tests would be the objectives to be intercommunicate.Importance of staph aureus to humansThe greatness of staphylococci aureus to humans would be outlined by a polish up of the stall structure, cell physiology and environmental niches, followed by the medical implications of Staphylococcus.Cell structureStaphylococcus is a cocci bacterium. As a member of the bacteria domain, it is expected that Staphylococcus has bacterial cell structure. In different(a) words, it lacks heart and soul and membrane-bound organelles. The structural elements in a cell of Staphylococcus should include a cell membrane, cell wall, ribosome and nucleoid (Campbell et al. 2009, p.98). On the other hand, it is worthwhile to note that Staphylococcus does not have flagella and spores (Paniker 2005, p.193).In addition to the above structures, Staphylococcus aureus possesses show proteins that help attachment to proteins such(prenominal) as the fibronectin and fibrinogen-binding proteins involved in phone line clotting (Baron 1996). This cellular property whitethorn explain the pathogenic nature of Staphylococcus aureus, as invasion might occur via wounds and ab rasions.Cell physiologyThe cell physiology of Staphylococcus covers temperature, pH, osmolarity and oxygen requirements, as well as cell division.Staphylococcus typically grows from a temperature of 20oC to 40oC, with optimum temperature being 37oC (Todar 2000). Concerning the optimum pH for metabolism, it ranges from 7.4 to 7.6 (Paniker 2005, p.193). For osmolarity, Staphylococcus requires a water activity of at least 0.85 for substantial out ripening (Todar 2000).As for oxygen requirement, Staphylococcus is facultative anaerobic (Willey, Sherwood Woolverton 2011, p.562). This implies Staphylococcus notify grow regardless of the aim of oxygen, that the presence of oxygen would be more favorable.Environmental nichesThe environmental niches of Staphylococcus fire be addressed by its interactions with other organisms as to where it is strand, how it synthesizes alimentals for growth and mutation.Staphylococcus is commonly found on the skin and mucose membranes of animals with poundle body temperatures, including humans (OGara and Humphreys 2001, p.583). The engaging environment along skin surface due to the production of eliminate may account for the abundance of Staphylococcus, since its enzymatic activity is at basic pH (Blood et al. 2007). The prominent bacteria from the genus include Staphylococcus aureus, which colonizes in nasal consonant cavity, larynx and on the skin surface (Andersson, Lindholm Fossum 2011). This may outline a parasitic relationship, in which Staphylococcus is the parasite and the animal supporting its growth is the host (Willey, Sherwood Woolverton 2011, p.725).In the presence of oxygen, Staphylococcus utilizes glucose to throng out cellular respiration, and electrons are passed on to the terminal acceptor, oxygen (Willey, Sherwood Woolverton 2011, p.562).When oxygen is lacking or absent, Staphylococcus may undergo fermentation and lactic acid is the wonted(prenominal) product (Willey, Sherwood Woolverton 2011, p.56 2). In the process, glucose is converted into substrate pyruvate, followed by its binding to the cofactor Nicotinamide type A Dinucleotide (NAD+) to produce lactic acid (Campbell et al. 2009, p.178)The interactions of Staphylococcus with the environment may as well as be underlined by mutation, which often occurs with Staphylococcus aureus. An example would be Methicillin-resistant Staphylococcus aureus (MRSA), a Staphylococcus aureus that is resistant to the antibiotic, Methicillin (Willey, Sherwood Woolverton 2011, p.562). The mutation is ownd by an alteration of the methicillin-resistance component (mec A) coding for a penicillin-binding protein (Davis 2011). This allows in failure of antibiotics to cure infections caused by Staphylococcus aureus, which will be addressed in the medical implication section.medical implications of StaphylococcusStaphylococcus deal present a great diversity of environmental, medical or biotechnological implications.Being a mesophile, Staphyl ococcus tummy carry out metabolism under normal room temperature. Together with the abundance of warm-blooded animals which act as hosts to provide a salty specialty, it base be said that Staphylococcus has an environmental implication of ubiquity.Statistics show that Staphylococcus aureus is present in 30% of healthy people (National Centre for Preparedness, spotting and Control of Infectious Diseases 2003). Though Staphylococcus may colonize on the skin surface of the host without causing any harms, its ubiquity can still give rise to various medical issues. The MRSA mentioned previously would be one of the problems associated with Staphylococcus. Apart from methicillin, MRSA could show resistance against many other antibiotics such as penicillin and amoxicillin (Agodi et al. 1999, p.638). The ineffectiveness of existing antibiotics to cure MRSA infections has resulted in deathlyity, and it is usually characterized by the incidence of septic shock and pneumonia (Klevens et al. 2007). A rapid enlarge of MRSA infections has been observed over the decades. The rate of hospitalized MRSA infections was only 2% in 1974 just this figure increases dramatically to approximately 40% in 1997 (Lowy 1998). This causes deaths of 19000 in the join States of America annually (Klevens et al. 2007). As Staphylococcus colonies on skin surfaces and mucous membrane, skin infections and diseases associated with mucous membranes could be another medical implication. It is known that Staphylococcus aureus may cause Scalded Skin and Toxic Shock syndromes. Moreover, it may cause pneumonia, urinary tract infections, food poisoning (Gill et al. 2004, p. 2426).Classification of StaphylococcusThe classification of Staphylococcus can be reviewed in terms of its morphology and some of the physiological properties stated above.MorphologyThe morphology of Staphylococcus can be described as cocci one thousand positive bacteria position in a cluster. This can be explained by its p roperty of cell wall and its behavior in cell division.The cell wall of Staphylococcus shows a gram positive reaction, which indicates its composition is essentially a compendious layer of peptidoglycan (Todar 2011). This property of cell structure helps the identification of Staphylococcus. Moving on to cell division, it can be predicted that Staphylococcus reproduce by double star fission. The reason for its cluster formation may be explained by its talent of undergoing binary fission in multiple planes with daughter cells remains proximal to each other (Paniker 2005, p.192). Though the daughter cells remain in polish proximity, the positions of attachment could vary and this leads to cluster being formed irregularly (Todar 2011).physiologic propertiesIn terms of thermal requirement, Staphylococcus is a mesophile. Regarding pH requirements, it is a neutrophile. Being a facultative anaerobe, Staphylococcus is catalase positive. The absence of flagella indicates that Staphylococc us is a non-motile bacterium. In addition, Staphylococcus aureus is coagulase positive but not for other species in the genus.As light is not readily available on skin surface and mucous membranes, it is proposed that Staphylococcus obtain energy via organic chemical compounds. Hence it is regarded as a chemotroph (Willey, Sherwood Woolverton 2011, p.137). The facultative anaerobic property of Staphylococcus may lead to a deduction that it utilizes organic carbon as the cite of electron when oxygen is present. Though some Staphylococcus may use reduced forms of inorganic nitrates to generate electrons, its preference towards an aerobic automatic teller machine should define it as an organotroph (Willey, Sherwood Woolverton 2011, p.137, 562). When comes to carbon source, Staphylococcus is a heterotrophy (Kumar, Hatha Christi 2007). That is to say, it attains its carbon source by converting organic substances for synthesis via oxidation (Voet, D, Voet, JG Pratt CW 2008, p.449). To sum up, Staphylococcus should be one of the members of the microbial group Chemoorganotrophic heterotrophs.Methods of Isolation of StaphylococcusThe methods of isolation of Staphylococcus would include growing in sensitive followed by streak plating. increase mediaTo en sure enough optimum growth of colonies, Staphylococcus should be enriched in solid food lineage with sodium chloride (NaCl) before plating on a nutrient agar-agar. A nutrient broth normally consists of beef extract and peptone as fuels for growth (Willey, Sherwood Woolverton 2011, p.148). The addition of salt allows a discriminating medium for Staphylococcus as it predominantly grows in salty environment.Alternatively, a growth medium can be done via a Mannitol salt agar (MSA), which consists of 7.5% of NaCl and a pH indicator. MSA essentially acts as both a discriminating and differential medium. NaCl selects for saline-favored Staphylococcus and the pH indicator differentiates between Staphylococcus aureus and Staphylococcus epidermidis. Differentiation can be illustrated by the fact that Staphylococcus aureus utilizes mannitol in the agar for metabolism, and the generation of acidic product is indicated by a yellow color. However, this phenomenon does not apply to non-pathogenic Staphylococcus (Willey, Sherwood Woolverton 2011, p.147).Streak Plating interest enrichment, Staphylococcus in the medium can be transferred to an agar nursing home with nutrient broth and salt, by employment of aseptic techniques. At the analogous time, a transfer to an agar plate with only nutrient broth should be performed as a control set-up. This is to ensure the effectiveness of the selective media because other bacteria could grow on the agar plate if the medium was not set up properly.Afterwards, the plates would be incubated for a week. Incubation should be done at 37oC as it is the optimum temperature for Staphylococcus to grow. Plating and pensiveness should be repeated a few times to make sur e that the colonies grown are pure.Identification by biochemical testsThe identity of Staphylococcus cannot be confirmed by carrying out the gram reaction wholly due to the fact that a great variety of bacteria from other genus may also show gram positive reaction. thusly, some biochemical tests have to be performed to verify that the bacteria isolated is in the genus of Staphylococcus and it is of the species Staphylococcus aureus. These tests include catalase, motility and cogulase.First of all, as Staphylococcus aureus is facultative anaerobic, it is expected that it contains enzymes to break down harmful products such as melt radicals generated along its aerobic pathway (). In this case, the enzyme of interest is catalase, in which its presence allows the breakdown of toxic hydrogen peroxide (H2O2) into oxygen and water (). Therefore colourless gas bubbles can be observed when H2O2 is added to a addiction of Staphylococcus aureus.Moreover, as Staphylococcus aureus is non-mot ile, motility test can be performed. In a motility medium supplied with carbon source, a rap color can only be observed along the stab line (). This essentially means that the growht Staphylococcus aureus is localized and its colonies are not motile.Furthermore, the identification test between Staphylococcus aureus and other bacteria from the genus would be based on its reaction with coagulase. Staphylococcus aureus readily coagulates plasma but not for others species in the genus (Willey, Sherwood Woolverton 2011, p.750). To ensure accuracy of the test, it is preferable to test on colonies extracted from culture plates that are known to contain coagulase positive Staphylococcus aureus and coagulase prohibit Staphylococcus epididymis respectively. The former acts as a positive control, while the latter(prenominal) acts as a negative control.ConclusionIn conclusion, Staphylococcus is a ubiquitous bacterial genus that can pose various medical implications and it can be grown, isola ted and identified based on its, environmental niches, morphology, physiological and structural characteristics. The aims of isolation and identification of Staphylococcus aureus can be achieved by a review of the four objectives as summarized below.Firstly, it is often found on epidermis of animal skins including humans and its ability to metabolize optimally at 37oC and at pH of 7.4-7.6 makes it a potential pathogen to humans. In particular, the species Staphylococcus aureus can cause a great diversity of diseases and the mutated Methicillin-resistant Staphylococcus aureus could be fatal owing to its resistance to most antibiotics.Secondly, it can be classified by in terms of morphology and some of the physiological characteristics. Its morphology is gram positive cocci bacteria growing in clusters. It is a mesophile, nuetrophile and facultative anaerobe. It is catalase positive and only Staphylococcus aureus is coagulase positive. The energy, electron and carbon sources of Staphy lococcus aureus can be described as chemoorganotrophic heterotrophic.Thirdly, regarding growth medium, the sample of cat hair should be enriched in a medium of sodium chloride before incubating on an agar plate of nutrient broth and salt at 37oC. The colonies should be streaked plated a few times to remove contaminants. This increases the efficiency of isolation of Staphylococcus aureus.Lastly, Staphylococcus aureus can be identified by the catalase, motility and coagulase tests. It is expected that bubbling is observed as a positive result with the catalase test. As for the motility test, a negative test is expected. In other words, no growth is observed across the stab line. Clumping of plasma is seen as a positive result and this differentiates Staphylococcus aureus from other species in the genus.