Running head: RESEARCH DESIGN TO IDENTIFY BIOTHREATS USING 1

Transcription

1 Running head: RESEARCH DESIGN TO IDENTIFY BIOTHREATS USING 1 Research Design to Identify Biothreats using MALDI-TOF-MS Technology Patricia Bolivar Walden University Quantitative Reasoning and Analysis RSCH H - 5 Dr. Mary Lescoe-Long December 23, 2012

2 RESEARCH DESIGN TO IDENTIFY BIOTHREATS USING 2 Research Design to Identify Biothreats using MALDI-TOF-MS Technology Introduction The intend of my quantitative research is to find out if using the new technology and methodology of Matrix Associated Laser Desorption/Ionization (MALDI) Time of Flight (TOF) mass spectrometry (MS) currently used for fingerprinting and identifying multiple microorganisms would circumvent the limitations of using conventional microbiological, immunological, and molecular methods such as polymerase chain reaction (PCR) for the analysis, detection, and speciation of Brucella species (Bolivar, 2012). Since an immediate response is required to mitigate the effects of a bioterrorism attack and reduction in exposure, it is essential that a timely and accurate detection of a biological event caused by a biothreat agent such as Brucella species, takes place. As a public health epidemiologist researcher, I am about to test the hypothesis which states that MALDI-TOF MS will provide a more rapid, accurate, and less costly method for the identification and speciation of Brucella species pathogens than conventional identification methods. When I am about to test this hypothesis I will face some fundamental problems that must be solved before the project is started: How many samples should be tested and compared? What shall be observed? How the data will be collected? What kind of analysis is adequate? Can I relate my results to the theoretical framework of my study? According to Frankfort-Nachmias & Nachmias (2008) the research design is the blueprint that would enable me to come up with solutions to these problems and will guide me to the various stages of the research. In this experiment identification of what is being compared must be made and the variables also need to be specified so that it is clear to the reader what the independent and dependent variables are and what outcomes are being measured (Creswell, 2009).

3 RESEARCH DESIGN TO IDENTIFY BIOTHREATS USING 3 Purpose of this Assignment The purpose of this paper is to evaluate the experimental and quasi-experimental research design, assess the strengths and limitations of each, recommend a quantitative design for my research plan, provide a rationale for choosing the most appropriate design, and state reasons why the design not chosen is not appropriate for my research question, hypotheses, and variables. Experimental versus Quasi-experimental Research Design The criteria of an experiment are manipulation and control; therefore, the difference between true experimental design and a quasi-experimental design must be established. According to Crosby, DiClemente, and Salazar (2006) a true experimental design must include more than one group, common measured outcomes, and random assignment. The true experimental design allows for causal inferences and has the highest level of control possible in real world settings. Experimental design entails manipulation of a variable to test the effects of the manipulation in some outcome (Crosby, DiClemente, and Salazar, 2006). A quasiexperimental design approximates a true experiment in that there is a treatment to examine and outcome measures. The difference is that quasi-experiments do not use random assignment to create groups for comparison on the outcome measures (Crosby, DiClemente, and Salazar, 2006). Quasi-experiments are considered causal research, but the differences with experimental design are the limited ability of quasi-experimental design to rule out alternate explanations, level of control, and the ability to infer causation.

4 RESEARCH DESIGN TO IDENTIFY BIOTHREATS USING 4 The Quantitative Experimental Research Study The heart of my research rests on scientific explanation of causality or association of a more rapid, accurate, and less costly method to identify and speciate Brucella species, a biothreat agent, in order to provide a faster and timely response during a potential bioterrorism attack caused by any of the three Brucella species affecting humans; Brucella melitensis, Brucella abortus, or Brucella suis. The independent variable is the method of identification and speciation in a single test provided by MALDI-TOF MS methodology which is expected to produce a change in the dependent variables direction and magnitude (rapid, accurate, cost effective report of Brucella species organisms, and reduction in response time to a biothreat). However, if I observe in my study than whenever the independent variable varies, the dependable variable changes too, it does not necessarily mean that a cause-and-effect relationship exists (Frankfort- Nachmias & Nachmias, 2008). I plan to demonstrate causality by demonstrating covariation; to infer that MALDI-TOF MS methodology rapidly, accurately, and less costly identify and speciate Brucella species will shorten time of report and directly causes a reduction in time of response to either an overt or covert bioterrorism incident, second that the correlation or association is not spurious; the relation between the two variables cannot be explained by a third one; and finally time order; demonstrate that the assumed cause occurs first prior to the assume effect (Frankfort-Nachmias & Nachmias, 2008). Even though my quantitative research study is under real laboratory conditions for the testing and comparison of methodology to identify and speciate a biothreat, time of response to a potential bioterrorism attack is dependent not only on availability of the laboratory results, but on the matrix used to spread the biothreat agent, available resources, and the overall bioterrorism preparedness and response mechanisms and algorithms in place. My study will not fulfill the

5 RESEARCH DESIGN TO IDENTIFY BIOTHREATS USING 5 requirements of a true experimental design. I recommend for my study the quasi-experimental design; randomization of my samples will not be possible, therefore, it cannot be considered a true experimental design. I will not able to assign a control group since I will be testing all the organisms by different methods and comparing testing time, results accuracy, and cost of testing. I will be using approximately 270 Brucella species isolates identified and speciated by conventional culture, biochemical, and PCR; all laborious and time consuming tasks, which will be compared with the fast, and rapid technology MALDI-TOF MS currently used to identify non biothreat organisms. In experimental research design two main characteristics are the manipulation of an independent variable and control over extraneous variables (Frankfort-Nachmias & Nachmias, 2008). The researcher choses, manipulates, and controls the independent variable to determine its effects on the dependent variable (Crosby, DiClemente, and Salazar, 2006). The dependent variable is the outcome variable of interest, in this case the dependent variables are the rapid, accurate, cost effective report of Brucella species organisms identification, therefore, reduction in response time to a bioterrorism attack caused by this biothreat agent. The internal validity of the study depends on the ability of the design chosen to test what the hypothesis was designed to test (Crosby, DiClemente, and Salazar, 2006). Possible threats to the internal validity of this study are maturation, testing, and instrumentation; by the time the study is conducted, data collected, and analysis performed; the rapid evolution of technology to identify biological agents of terrorism may provide to the scientific and clinical community similar or even better biothreats identification systems than MALDI-TOF MS, Brucella species may be reclassified as a non-biothreat select agent, or the bioterrorism preparedness and response program may not receive any more federal funding. This quantitative experimental study will be conducted in two

6 RESEARCH DESIGN TO IDENTIFY BIOTHREATS USING 6 parts the first part is the actual testing in a controlled laboratory environment with pathogens to establish a comparison in methodology, the second part of the study will be based in theoretical models of interdependence of action/ response to a potential bioterrorism incident and the timely identification of the causative biological agent. Using the quasi-experimental design will provide some control over extraneous variables which will increase the confidence that observed outcomes are the result of MALDI-TO MS innovations in identification and speciation of biothreat agents Brucella species organisms, thus enhancing internal validity. External validity or generalizability of this research study will be affected by the representativeness of the sample and reactive arrangements (Frankfort-Nachmias & Nachmias, 2008). In a similar study conducted by Lista et al (2011) the authors used 152 Brucella species isolates for the generation of the reference library for MALDI-TOF. I plan to use at least 270 Brucella isolates, a representative sample of good proportion which reflects the characteristics of a possible agent used in a bioterrorism incident since all of the strains were isolated since 2003 from patients who were affected by the organism after consumption of contaminated cheese or meat in the United States or Mexico. Conclusion The main advantage of using the quasi-experimental design for my study is that it allows me to carry out my study in natural, real life setting using laboratory samples when making comparisons of methodology to identify and speciate Brucella species and relate those results to the theoretical frame of interdependence of action- bioterrorism response, thus increasing the internal validity of my study.

7 RESEARCH DESIGN TO IDENTIFY BIOTHREATS USING 7 References Bolivar, P. (2012). Identification of Biothreats using Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI -TOF) Technology. Walden University Quantitative Reasoning and Analysis RSCH H-5. Dr. Mary Lescoe-Long. Creswell, J. (2009). Research design: Qualitative, quantitative and mixed methods approaches. Thousand Oaks, CA: Sage publications. Frankfort-Nachmias, C., & Nachmias, D. (2008). Research methods in the social sciences (7th ed.). New York: Worth. Lista, F., Reubsae, F., De Santis, R., Parchen, R., Jong, A., Kieboom, J., Paauw, A. (2011). Reliable identification at the species level of Brucella isolates with MALDI-TOF MS. Biomedical Central Microbiology 11(267). Salazar, L., Crosby, R., & DiClemente, R. (2006). Choosing a research design. In Crosby, R., DiClemente, R., & Salazar, L. (Eds.), Research methods in health promotion (p ). San Francisco, CA: Jossey-Bass.