Vancomycin resistant Enteroccocci
Vancomycin-Resistant Enterococci (VRE) is one of the major concerns of scientists. Resistance is a strategy adopted by many microorganisms to survive against adverse environmental barriers. Many laboratory techniques are available to detect resistance. This research paper compares two selective for isolation of VRE from Stool Specimens (SS).
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Transmission of VRE is a problematic health care issue. For the past 15 years, severe infections clinically led to high prevalence rates globally. The bacterium Enterococcus Faecium is considered as the commensal of gastrointestinal tract and is responsible for opportunistic infections in seriously unhygienic individuals (1). Opportunistic infections are of special concern in patients with poor immunity since this microbe has become an important pathogenic agent for nosocomial infections in the past two decades (1). Various studies have reported the animal-derived and human Enterococci Faecium which isolates using techniques like multilocus sequence typing that indicated the role of genetic lineage CC17 in hospital based infections (1).With this, the severity of infections has gained momentum. Hence, in order to delay the spread of this microbe preventive strategies are drawing the attention of health care professionals in hospitals.
Disease causing potential
Identification of non-infected but gut inhabited individuals is an important aspect of health care strategies in treating and preventing spread and development of infections with regard to the control measures such as tests and monitoring. The approach related to identification of gut-inhabited individuals aimed at detecting the potential threat would indicate the VRE spreads from these patients. Therefore, identification of microbe seems important for the control of infection (1).
Fecal specimens were selected for the detection of VRE as it is considered essential for the vancomycin-resistant enterococi, follow up of epidemiological infectious disease and nosocomial prevention measures (2). The studies are aimed at comparison of different characteristics of bacteria revealed that when ChromID VRE medium is compared to the bile esculin agar, which is a modified medium, ChromID VRE, is proved to be the ideal medium for rapid detection of vancomycin-resistant microbes such as E. faecalis and E. faecium (2). This reaction occurs because earlier no proper standardized consensus was set for methodology and its precise application where vancomycin concentration and medium base was described (2).
Culture based methods: ChromID VRE (C-ID) and CHRO Magar VRE (CHR) media
The current paper is based on a comparative study conducted using the data about the characteristics of the medium between chromID VRE (C-ID) medium and CHRO Magar VRE (CHR) medium. This has been done taking into consideration the media’s potential in facilitating the identification of VRE from clinical stool specimens, the stable color of colony and its development features, as well as selectivity. Strains belonging to Enterococcus have been used for evaluating the selection potential of two media. For comparisons, positive controls belonging to VRE reference strains are employed which have been gathered from National Reference Center for Streptococci and culture collections.
The experiment procedure contained several methods that were aimed at facilitating the process of data collection for further processing. Confirmation of enterococci was determined by 5-min pyrrolidonyl arylamidase spot and gram staining of suspected VRE colonies. Exposure of colonies to drugs like furazolidone dosed 50g and mupirocin of a 10g dose with Rosco Neo-Sensitabs on Mueller-Hinton agar and a rapid D-xylose fermentation test with Rosco Diatabs enabled the identification of enterococci at species level.The selection of appropriate treatment measures enabled the detection of E. faecalis. Resistance to vancomycin and teicoplanin was determined by the CLSI breakpoints and Mutiplex PCR was used to check the presence of vancomycin. This supported the recent work that described the development of multiplex PCR method that enabled rapid identification of genotypes vanA, vanB, vanC1, and vanC2/C3 genes (3). VREfm isolates were checked for the genetic relatedness. Based on the characteristics of bacterial species, this technique is used to determine their distribution and facilitates the discrimination of detrimental pathogenic candidates (4).
Results and Discussion
The applied technique facilitated detection of all MT’s except for MT-332 belonging to the clonal complex 17 (CC17) (5). This complex is related to infections and nosocomial outbreaks. The sensitivity of two media was 98.2% (56/57) with the specificities of 96.5% (195/202) for CHR medium and 97.5% (197/202) for C-ID medium. However, sole dependence on other methods like colony pigmentation on chromogenic medium and gram staining alone would increase the chances of obtaining false-positive VRE identification. For instance, the growth of Pediococcus species interferes with the Enterococci species in the two media and ultimately from the VRE medium the Pediococcus growth becomes difficult to discriminate (6).
These findings have shown that both media C-ID and CHR have totally addressed the detection issues of VRE. In this case, it is important to note that excessive growth of non-specific bacteria and yeasts could suppress the medium evaluative properties. With this in mind, scholars should take into account that stool specimens are not considered for plating directly on to the media. However, this could be overcome in the process of selective enrichment technique when stool specimens are compulsorily pre-cultured overnight.
Evaluation of the Article
The article under consideration is aimed at comparing to scientific methods (7). It cannot be regarded as fully original since it is largely based on two approaches which are used in the contemporary microbiology. On the other hand, it can be regarded as creative since it is aimed at identifying the most efficient methods out of the two most used methods. Admittedly, this is also important for the development of the overall study since the identification of the most efficient approach will help researchers save time and costs.
The authors provide detailed description of the two methods and draw the necessary conclusion. Notably, the authors are really precise and concise. It is easy to follow the article. More so, other researchers can use the article as a guideline for implementing the two methods. However, it is also possible to note that the description of the methods is too detailed whereas the researchers’ conclusions are rather short. It would be better if researchers revealed their conclusions in more details. Nonetheless, it is possible to conclude that the article provides in-depth analysis of the two approaches and provides concise conclusions that make it a valuable source for many researchers.
Title and Abstract
It should be admitted that title is a bit long for the reader to comprehend its essence and the main idea on the sport. Nevertheless, the title accurately reflects the content of the paper because it has clear structure, despite the length. The structure of abstract is a bit ambiguous because the author fails to present this part of the research paper in a consistent way. Notably, the abstract of the paper is too short to present the main topic, the methods and material used, and finding and results sections and the conclusion itself. The latter is absent as well, and therefore, it is difficult to understand the essence and significance of the paper. However, the brief idea is still possible to grasp.
Before presenting the topic of the research as well as its main significance, the author resorts to a brief overview of the terms and background to introduce the reader to the problem. Therefore, the introduction is well structured and organized presenting the main research objectives as well as specific concepts that will be further useful in solving the problem and providing the research findings. Although the introduction is too short, it manages to engage the audience immediately into the research process itself. Despite the presented strengths, introduction has certain weaknesses as well. Specifically, no mentioning is present concerning the importance of the research as well as its further implications.
Overview of Methods and Materials
The presented research tools were quite relevant for identifying the major research objectives. Moreover, the researchers manage to describe in detail the major instruments that have been used, including the explanation for their reliability and validity. It should also be stressed that the scholar has successfully managed to use a diverse range of methods, including culture-based methods, detection of enterococci, stool specimen, genotyping multiplex PCR. The section also involves the assessment of genetic relatedness. Comparing the applied method with related researchers, it should be stressed that the section has a sufficient bulk of used instruments. What is more important, the author approaches the investigation with even greater diligence by pointing out the incubation period, the amount specimen used, and the means with the help of which the experiment has been conducted. Besides, the researchers refer to reputable sources which make the article feasible.
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While presenting the results of the study, the scholar has partially referred to other related studies that used similar techniques for introducing the research findings. Specifically, the research focuses on the assessment of other chromogenic media used to test the resistance of enteroccoci to the vancomycin (1). The evaluation of rectal swabs and stool samples has introduced new insights into research and provided the research with new opportunities to reduce the paradigmatic separatism of the given research. The rest of the study has solely premised on the findings and tests conducted by the scholar, which are consonant with the research aims and objectives. In addition, the article provides a list of tables and figures revealing the outcomes of the research to enhance the comprehension of results.
An in-depth consideration of the result has revealed that the author’s ideas and findings are congruent with my assumptions concerning the research objectives. In particular, the researchers have managed to deliver the information about testing in a consistent way. Although, the article relies on other researchers, it still discloses it own evaluation of the findings provided by other scholars. Specifically, the researchers have withdrawn specific concepts and hypotheses to build their own and introduce more effective methods of research. Nevertheless, this section present succinct evaluation of the methods used as well as findings obtained; further, there is not mentioning about the significance of the study in whole.
As far as the conclusions are concerned, it is possible to note that the researchers provide definite conclusions, but they do not go into details. However, it would be beneficial for the article to provide more detailed consideration of the conclusions. This would help many researchers understand the difference between the methods and use the most effective during certain experiments.
All the references introduced by the author are relevant to the topic of the research. At this point, the scholars apply to different articles that present their quantitative and qualitative studies discussing the problem of enterroccocus, the usage of vancomycin, and comparative analysis of cromogenetic media. Through the examination of these dimensions, the researchers have greatly contributed to the outcome of their empirical observations because they assumptions are logical and reliable. In addition, the sources they have used are valid and reliable because most of them are based on evidence-based practice and effective research design. This makes the given research more straightforward and specific.
Tables and Figures
Notably, the researchers provide sufficient number of figures and tables which illustrate their findings. All figures and tables have the necessary legends and this makes them easy to understand. Admittedly, these figures and tables help the reader to analyze the data provided. It should also be stressed that the figures and tables are distributed throughout the paper within the correspondent sections, which is a great advantage for the readers to immediately view the results. Visual aids seem to be more effective when presented in the body of the paper, but in the appendices, which enhances the integrity of the paper in general.
List of References
Delmas, J., F. Robin, C. Schweitzer, O. Lesens, and R. Bonnet. 2007. Evaluationof a new chromogenic medium, ChromID VRE, for detection of vancomycin-resistant enterococci in stool samples and rectal swabs. J. Clin. Microbiol. 45:2731–2733.
Kuch, A., K. Stefaniuk, T. Ozorowski, and W. Hryniewicz. 2009. New selective and differential chromogenic agar medium chromID VRE, for screening vancomycin- resistant Enterococcus species. J. Microbiol. Methods. 77:124– 126.
Sameer Elsayed* and Nina Hamilton. Improved Primer Design for Multiplex PCR Analysis of Vancomycin-Resistant Enterococcus spp. J Clin Microbiol., 2001.39: 2367–2368.
Top, J., R. Willems, S. van der Velden, M. Asbroek, and M. Bonten. 2008. Emergence of clonal complex 17. Enterococcus faecium in The Netherlands. J. Clin. Microbiol., 46:214-219.
Top, J., L. M. Schouls, M. Bonten, and R. Willems. 2004. Multiple-locus variable-number tandem repeat analysis, a novel typing scheme to study the genetic relatedness and epidemiology of Enterococcus faecium isolates. J. Clin. Microbiol., 42:4503–4511.
Mastro, T. D., J. S. Spika, P. Lozano, J. Appel, and R. R. Facklam. 1990. Vancomycin-resistant Pediococcus acidilactici: nine cases of bacteremia. J. Infect. Dis., 161:956-960.
Peltroche- Llacsahuanga, II., J. Top, J. Weber-Heynemann, R. Lütticken, and G. Haase. 2009. Comparison of Two Chromogenic Media for Selective Isolation of Vancomycin-Resistant Enterococci from Stool Specimens. J. Clin. Microbiol. 47: 4113-4116.