Introduction
This essay presents a literature review and project proposal focusing on antibiotic resistance in bacterial pathogens, a critical issue in modern biomedical science. The purpose is to synthesise existing knowledge on the topic through a structured review of academic sources and to propose a feasible research project suitable for a BTEC Science context. The literature review will explore the historical context, definitions, and key studies, while the project proposal will outline a hypothesis, aim, objectives, methodology, timeline, and potential limitations. The discussion is designed to provide a broad understanding of the topic, supported by evidence, while maintaining a critical perspective appropriate for undergraduate study.
Literature Review
Historical Context and Definitions
Antibiotic resistance, defined as the ability of bacteria to withstand the effects of antimicrobial drugs, has been a growing concern since the mid-20th century. The discovery of penicillin by Alexander Fleming in 1928 marked the beginning of the antibiotic era, revolutionising medical treatment (Fleming, 1929). However, resistance emerged shortly thereafter, with Staphylococcus aureus demonstrating resistance to penicillin by the 1940s (Ventola, 2015). This phenomenon arises through mechanisms such as mutation or horizontal gene transfer, often accelerated by misuse and overuse of antibiotics in healthcare and agriculture (Davies and Davies, 2010).
Methods and Previous Experiments
Numerous studies have been conducted to investigate the mechanisms and spread of antibiotic resistance. Experimental approaches typically involve in vitro susceptibility testing, such as the Kirby-Bauer disk diffusion method, to assess bacterial response to various antibiotics (Bauer et al., 1966). Additionally, molecular techniques, including polymerase chain reaction (PCR), have been employed to identify resistance genes, such as the blaTEM gene associated with beta-lactamase production (Davies and Davies, 2010). Epidemiological studies have also highlighted the global prevalence of resistant strains, notably methicillin-resistant Staphylococcus aureus (MRSA), with significant implications for public health (Ventola, 2015). Despite these advancements, gaps remain in understanding how environmental factors contribute to resistance development.
Project Proposal
Hypothesis and Explanation
It is hypothesised that exposure to sub-lethal concentrations of antibiotics will increase resistance in Escherichia coli over successive generations. This prediction is based on the principle of selective pressure, where bacteria surviving low doses adapt through mutations or gene acquisition, as supported by prior research (Davies and Davies, 2010).
Aim and Objectives
The aim of this project is to investigate the development of antibiotic resistance in E. coli under controlled conditions. Objectives include culturing E. coli in varying antibiotic concentrations, measuring changes in minimum inhibitory concentration (MIC), and documenting resistance patterns over time.
Summary of Methods and Equipment
E. coli cultures will be grown in nutrient broth with incremental concentrations of ampicillin. Equipment required includes a laminar flow hood, autoclave, petri dishes, antibiotic disks, and a spectrophotometer for optical density measurements. Susceptibility testing will be conducted using the disk diffusion method.
Timeline
Health and safety paperwork is anticipated to be completed within the first week. Laboratory work, including culturing and testing, is planned over a four-week period. Report writing and data analysis are expected to span an additional two weeks, concluding the project within eight weeks.
Potential Limitations
Limitations may arise from restricted laboratory time and resources, potentially affecting the scope of testing. Furthermore, practical skills and access to advanced genetic analysis tools may constrain deeper investigation. Institutional facilities might also limit the range of antibiotics tested.
Conclusion
In summary, this essay has reviewed the historical and scientific context of antibiotic resistance, drawing on established studies to highlight its mechanisms and prevalence. The proposed project offers a practical approach to studying resistance development in E. coli, with clear objectives and methods, though limitations such as resource constraints are acknowledged. The implications of this work lie in contributing to the broader understanding of resistance patterns, potentially informing strategies to mitigate this global health challenge.
References
- Bauer, A.W., Kirby, W.M., Sherris, J.C. and Turck, M. (1966) Antibiotic susceptibility testing by a standardized single disk method. American Journal of Clinical Pathology, 45(4), pp. 493-496.
- Davies, J. and Davies, D. (2010) Origins and evolution of antibiotic resistance. Microbiology and Molecular Biology Reviews, 74(3), pp. 417-433.
- Fleming, A. (1929) On the antibacterial action of cultures of a penicillium, with special reference to their use in the isolation of B. influenzæ. British Journal of Experimental Pathology, 10(3), pp. 226-236.
- Ventola, C.L. (2015) The antibiotic resistance crisis: part 1: causes and threats. Pharmacy and Therapeutics, 40(4), pp. 277-283.
