Virology and Microbiology - Molecular vs Culture-Based Diagnostic Techniques - Essay Example

Name: Date: Institution: VIROLOGY AND MICROBIOLOGY Common culture-based techniques 1) Blood culture, the positive blood culture has for long been used in the identification and testing micro-organisms. This is done without the having a surgical operation on the heart valves. However, this method has some great risks of contamination. It also experiences a challenge in that there is no specificity of the pathogens (Brooks, Butel, & Morse, 2006). This makes it difficult to interpret the results that have been made and may lead poor prescription by the physicians. It also takes the time to get the results since few days could be required for bacterial growth in order for them to be detected. Blood culture has a crucial role in antibiotic therapy. However, there are a number of factors that has been initiated before the sampling of blood (Richman, Whitley, & Hayden, 2009). A negative diagnostic impact may be experienced as a result of the presence of the fastidious microorganism. 2) Valve culture; the heart valve tissues are not easily available not unless if the patient has undergone the replacement of the heart tissues. The resected tissues are the best materials as they have a large number of bacteria and that it is the main attention of the contagion. This method also has its own drawback in that, researchers have argued that its failure may be accounted to the antibiotic administrated to the patients before they undergo a surgery. 3) Serology; the results of serology are linked to the regional epidemiology of the causal organism. However, its test tends to differ in terms of sensitivity as well as its specificity. Molecular techniques Clinical microbiology has greatly appreciated the use of molecular techniques due to the strong sensitivity and specificity in the identification and detection of pathogens. These molecular techniques include; the nucleic acid amplification techniques, this method is theoretically believed to detect about 1-10 microbial organisms. It has a lower sensitivity to in clinical specimen. This is what will make this method difficult in the determination and interpretation of the results. There is also a likelihood of false negative results; this may occur from the extraction of the DNA and may have a difference in efficiency due to the following considered factors, the cell wall of the bacteria, the technique used, also a size and the plenty of the fragment augmented, and inhibitors’ presence. The technique is susceptible to contamination due to the presence of the infecting bacterial from DNA; reagents, the way of handling, and the plastic apparatus used such tubes and the tips of a pipette. This method is expensive and time-consuming since every step used must have a control experiment as well as trained personnel. According to Chakravorty, Helb, Burday, Connell & Alland, (2007) the polymerase chain reaction (PCR) is one of the nucleic acid amplification techniques used by physicians in the bacterial DNA detection. PCR is a sensitive method and it targets the 16S ribosomal DNA. This gene has got two regions which include; the variable region and the conserved region and is responsible for the design of the genus. The PCR method was initially time-consuming since it involved incubation of the blood samples, however over the time it has improved and it only involves blood samples without a prior incubation. This method does not account for the viability and as a result, it may indicate bacterial DNA as a positive result. Comparison between molecular and culture-based diagnostic techniques The two diagnostic methods; culture and molecular methods experience some challenges. Such challenges will include the diagnostics of chronic polymicrobial infections that could, for example, be found in wounds. In the recent study, it has been found that; most of the bacteria identifiable with culture testing can as well be identified with molecular testing. Contrary, most of the bacteria that were identified with molecular testing were not identified in culture testing. Advantages of molecular testing i. It is more sensitive to microbial identification compared to the culture testing. The molecular test has an advantage over culture test in that it is too sensitive to detect microbial organisms at low levels. ii. It is also fast in that it will save time compared to the culture based; this will ensure that the physicians will prescribe specific antibiotics to treatments without making errors on assumptions based on the symptoms as they give the medication. iii. It also has a reduced turnaround time compared in relation to culture test method. Drawbacks of the molecular test in comparison to culture based technique, i. It is too costly, financial analyses are one of the factors that microbiology laboratory should consider before they opt for the molecular test method. The high cost is linked to the high skilled personnel by the medical practitioners. It may also be linked to the advancing technological level. ii. Over a period of time organisms may undergo mutations and in case these microbial organisms undergo mutation this technique may not easily detect the mutation (Matthijnssens, Ciarlet, McDonald, Attoui, Bányai, Brister, & Iturriza-Gómara, 2011). iii. In molecular test due to contamination, false positive are likely to be detected or false negative detected as a result of the failure of the process of detection itself. The contamination may come from contamination of the specimen; apparatus used and may also arise from the way the specimen is handled. iv. It also requires more skilled personnel, this may be associated to the high level of cost involved in diagnosis, and finally, a precise work flow is required since for it to be effective the technologists have to progress in a series of steps in a specified order. Limitations of molecular method i. It has not been in a position to determine the planktonic antibiotic susceptibility ii. It is also not in a position to define the biofilm bacteria’s sensitivity. Disadvantages of culture test i. It is time-consuming; the process described may take a period of 1-5 days before the results are given. It takes 24-72 hours after previous patient results presentation to avail new results of another patient. ii. Due to the slow running of the blood culture (BC) mostly in the poor health centers, no-specific antibiotics may be prescribed by the physicians. It has similar limitation to the molecular method but in addition, it is unable to determine antibiotic resistance components. According to the comparison between the two methods, it can be arrived that; in order to increase sensitivity and specificity of micro-organisms, and to improve the speed of diagnosis, molecular test should be advocated for. The molecular tools of diagnosis have also a positive contribution to the rapid diagnosis compared to the cultural test, mostly BC. Factors to be considered when developing a new diagnostic technique Cost; the financial condition is one of the major factors that should be considered while developing a new diagnostic method. According to Holland, & Kiechle, (2005) in case of a less expensive alternative method that has been in existence, there is no need to develop a new method which is expensive and particularly if it has the same level of specificity and detection would incur unnecessary financial constraints. Time, is also the other factor to be considered. The time taken to obtain the results needs to be reduced from several days as in the case of cultural methods to just few hours. For example, in culture based methods it ranges from one to five days. Malinowski, (2005) postulated that as new technological continues to improve, the time of obtaining the diagnostic results should be reduced to few hours. The other factor to consider is the work system; the diagnostic process will be successful, only if the work system is efficient. This system is composed of the following, team members, technologies, tasks, tools and organizational factors. The diagnostic team is made of; patients, physicians, and the family members of the patients. Tools and technologies on the other side include the medical information. It is also important to consider the external surroundings which include health care, payment as well as the legal environments. In setting up a new clinical setting the work system should be well organized in such a manner that it is effective for the diagnostic process (Lebanony, Benjamin, Gilad, Ezagouri, Dov, Ashkenazi, & Nonaka, 2009). The efficiency of the work system will lead to improvement of the patient cares. Specificity; as the specificity of the microbial organisms is very important to the physicians and other medical practitioners. With the right information, the medics are able to make the right decisions and hence improving the patient care Katsoyiannis, Terzi, & Cai, (2007) postulated that a new method to be set in place should have a strong specificity. In my view, the culture based methods of detection of the microbial organisms are unsatisfactory. The time taken in the analyses of the results need to be improved for the accuracy of the prescription by the medical practitioners. In that connection, molecular techniques would serve the best since they save on time. Due to the improvement in the molecular techniques, a larger number of bacteria can be detected and therefore it will help in the improvement of the patients care. The Cultural method is less expensive compared to the molecular test; however, the number of microorganisms molecular test is able to detect is much higher in relation to the number of pathogens detected by the cultural-based method Hutson, Airaud, LePendu, Estes, & Atmar, (2005). This improves on the specificity of the microorganisms and thus it should be encouraged as it reduces the chances of doctors prescribing wrong medications. The high level of skilled personnel involved in the molecular test will ensure that the patients are handled with care and professionalism. In the future, the molecular technologies will continue to improve; as a result, the turnaround time will continue to decrease and health practitioners will make the right decision and they will improve health care of their patients. In conclusion, the molecular diagnostic test continues to undergo technological improvement. The work system will also require skilled personnel so that to ensure efficiency in the working environment. In the future, the diagnostic tests will keep on improving as the technologies advance. Chambers, Shaw, Gatza, Fisk, Donehower, & Goodell, (2007) argued that the cultural based methods will continue to be discouraged since more pathogens are identified by the improved molecular techniques. The cost of molecular techniques has been another factor to hinder the efficiency in the methods of pathogen detection. The medical practitioners should consider the less expensive methods and only apply the expensive techniques where specificity is required. The time taken to obtain the results of diagnostic tests should be reduced (Lawn,& Nicol, 2011). By reducing the time between when the test is carried out and the time that the results are obtained ensure that the medics will give the right prescriptions on medication as they make their decisions. References: Brooks, G. F., Butel, J. S., & Morse, S. A. (2006). Medical microbiology. United States. 25th. Chakravorty, S., Helb, D., Burday, M., Connell, N., & Alland, D. (2007). A detailed analysis of 16S ribosomal RNA gene segments for the diagnosis of pathogenic bacteria. Journal of microbiological Chambers, S. M., Shaw, C. A., Gatza, C., Fisk, C. J., Donehower, L. A., & Goodell, M. A. (2007). Aging hematopoietic stem cells decline in function and exhibit epigenetic dysregulation. PLoS Biol, 5(8), e201. Holland, C. A., & Kiechle, F. L. (2005). Point-of-care molecular diagnostic systems—past, present and future. Current opinion in microbiology, 8(5), 504-509. Hutson, A. M., Airaud, F., LePendu, J., Estes, M. K., & Atmar, R. L. (2005). 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