The VITEK MS: The Future of Microbiological Species Identification
The VITEK MS is an autonomous mass spectrometer and software system that is intended to improve the speed at which microbiological species can be quickly identified. The system, which distinguishes and recognizes bacteria, fungus, and some viruses, has rapidly emerged as the most cutting-edge technology. The primary factor making VITEK MS the best system is that it delivers findings promptly, frequently in under a minute. Besides. The VITEK MS is able to recognize delicate samples. Additionally, the technology has shown improvements in workflow. Significantly, the system's outcomes are trustworthy and accurate (Sandle, 2014).
The Principle of the VITEK MS
The principle of the VITEK MS is as follows. After the sample preparation, the user introduces the sample into a high vacuum setting. The high vacuum environment, ionization occurs with a particular laser, which causes the sample to burst, discharging a protein cloud. The protein cloud is accelerated by the use of an electric charge while recording the time of the flight. For instance, the light proteins travel faster than the heavy protein cloud. In summary, the principle of the VITEK MS is to ionize chemical compounds to obtain charged molecules, and to them quantify their mass to charge ratio (Martiny, et al., 2012).
Procedure and Application
The procedure for the using the VITEK MS is as follows. Foremost, the user prepares the target slide and introduces it to an incredibly vacuum environment. In the vacuum environment, a particular laser beam strikes and splits the sample, releasing a protein cloud. Once the cloud is released, an electric charge is utilized in accelerating it. The protein cloud is passed through the ring electrode. The ring electrode records the time of flight since different protein clouds have a different speed of flight depending on their mass. The cloud of proteins is then detected by a sensor, creating a spectrum which represents the protein makeup of every individual sample (Dubois, et al., 2012). Then, the system automatically compares the spectrum from the sample with an extensive database of bacteria and fungi spectra, which are already characterized with precision. In the process of comparison, the identification can me noted at the family genus and species levels.
Applications in Medicine and Microbiology
The VITEK MS has widespread application in medicine and microbiology. For instance, a sample culture for determining a particular microorganism is prepared and placed on the slide. Through the above procedure, the proteins from the sample are compared with existing microbial organisms in the VITEK MS database, before identifying the organism based on its family, genus and species. Once, the organism is identified, treatment measures can then be administered to the patient presenting that bacteria or fungi.The VITEK MS is also used in research facilities to study new strains of bacteria and viruses. Because of the presence of many bacteria and viruses, research is vital in identifying new strains of micro-organisms, and including them in the database for further applications in hospital laboratories. Additionally, educational facilities, particularly for Microbiology utilize this system in learning activities and teaching the students how to identify strains of viruses, bacteria, and fungi using the VITEK MS.
Accurate Results for Improved Patient Care
The results of the VITEK MS are robust and accurate and necessary for the best patient care decision. The system interprets each spectrum as a series of peaks, which are detected through intensity and mass. In the presence of the Advance Spectra Classifier, the spectrum is distinguished efficiently since each peak is considered in the calculation and identification of the microorganism. The VITEK MS houses a database with a population of fungi, bacteria and virus strains. The system accounts for diversity among strains which fall within the same species. Hence, through the high level of differentiation, the attained results are usually accurate and robust. Using the VITEK MS system, modification of score is not necessary. The VITEK MS database can discriminate between species. The species distinguished can originate from various backgrounds including a geographical diversity of the isolates, isolates from a variety of origins such as blood and tissue. Besides, the isolates could be sub cultured in differing media or with varying incubation periods (Tan, et al., 2012).
An Example of the VITEK MS in Action
For example, the user can prepare and introduce a sample bacteria, which is ionized until the identification process. For instance, if the bacteria is E.coli, the VITEK MS will compare the protein from the sample with those available in the VITEK MS database. In a few minutes, the system can identify the previously unknown E.coli bacteria, with the results useful in patient care decision making.
Advantages and Disadvantages
Advantages
The benefits of the VITEK MS include the following. Foremost, the VITEK MS can identify a broad spectrum of bacteria, both gram positive and negative comprising of rods and cocci. Secondly, the system is efficient when detecting the anaerobic bacteria. Thirdly, the results of the systems are usually reproducible. Furthermore, the user can expand the system depending on their requirements. Significantly, a majority of the tests conducted using the VITEK MS only need a single colony in most cases (Sandle, 2015). Additionally, the system has been most successful in virus identification. Besides, the risk of exposure, when using the VITEK MS is low since the samples are inactivated through extraction before identification. Moreover, a majority of the bacteria, which have proven difficult to culture before, have successfully been identified using the VITEK MS. The VITEK MS also detects fungi, especially yeast. However, it only identifies limited strains of fungi such as Penicillium and Aspergillus. Finally, securing the equipment is relatively expensive, but the operation costs are extremely low.
Disadvantages
The microorganisms characterized by the possession of capsule do not respond to lysis. Hence, the extracted yield is always low leading to reduced quality spectra, which can cause misidentification. Therefore, because of the potentially false results, users recommend that the samples should be tested in duplicate. Secondly, the type of media utilized in the system can cause interference. The reason is that if the media selected during verification is not used as a standard, the results could be false. Thirdly, the VITEK MS has failed to identify many organisms, especially the Mycobacteria such as the Acinetobacter species. The reasons that Mycobacteria have a genetic relationship. Moreover, the presence of endospores can result in spectral interferences, particular with the Bacillus species of bacteria. Additionally, the system has failed to freely distinguish between similar organisms such as E.coli and Shigella species. Finally, the system has failed to make a distinction between various antibiotic sensitive and resistant strains of the same species (Sandle, 2015).
References
Dubois, D., Grare, M., Prere, M. F., Segonds, C., Marty, N., & Oswald, E. (2012). Performances of the Vitek MS matrix-assisted laser desorption ionization–time of flight mass spectrometry system for rapid identification of bacteria in routine clinical microbiology. Journal of clinical microbiology, 50(8), 2568-2576.
Martiny, D., Busson, L., Wybo, I., El Haj, R. A., Dediste, A., & Vandenberg, O. (2012). Comparison of the MICROFLEX LT and VITEK® MS systems for the routine identification of bacteria by Matrix-Assisted Laser Desorption-Ionization Time-Of-Flight Mass Spectrometry. Journal of clinical microbiology, JCM-05971.
Sandle, T. (2014). Approaching the Selection of Rapid Microbiological Methods. Journal of Validation Technology, 20(2), 1-10.
Sandle, T. (2015). Microbiological Identification with MALDI-TOF MS| IVT. Journal of Validation Technology, 21(3), 1-10.
Tan, K. E., Ellis, B. C., Lee, R., Stamper, P. D., Zhang, S. X., & Carroll, K. C. (2012). Prospective evaluation of a matrix-assisted laser desorption ionization–time of flight mass spectrometry system in a hospital clinical microbiology laboratory for identification of bacteria and yeasts: a bench-by-bench study for assessing the impact on time to identification and cost-effectiveness. Journal of clinical microbiology, 50(10), 3301-3308.
