Microbiology 1-8

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Questions and Answers

What does microbiology primarily study?

Ecosystem dynamics

Chemical reactions

Microorganisms (correct)

Human anatomy

Which of the following is NOT an area where microbiology plays an important role?

Human health

Astronomy (correct)

Agriculture

Pharmaceuticals

Which textbook is authored by Willey et al.?

Brock Biology of Microorganisms

Principles and Practice of Disinfection

Prescott’s Microbiology (correct)

Hugo & Russell’s Pharmaceutical Microbiology

What is the primary purpose of studying microbiology?

To gain awareness of microorganisms and their roles Signup and view all the answers

Which of the following areas of study is least likely to be associated with microbiology?

Quantum physics Signup and view all the answers

What does the term 'microorganism' include?

Viruses, fungi, and bacteria Signup and view all the answers

Which publisher is associated with the book 'Brock Biology of Microorganisms'?

Pearson Signup and view all the answers

What type of virus does Gardasil specifically target?

Human papilloma virus (HPV) Signup and view all the answers

Which of the following correctly describes Gardasil's composition?

Contains recombinant viral protein produced in a bacterium Signup and view all the answers

How can pharmaceutical products be affected by microorganisms?

Causing economic loss Signup and view all the answers

What kind of media can be used to grow microbes in a laboratory?

Solid and liquid media that are nutrient-rich Signup and view all the answers

What is the purpose of specialist media in microbiology?

To identify unknown microbes and selectively culture specific microbes Signup and view all the answers

Which microscopy technique is best suited for observing viruses?

Electron microscope Signup and view all the answers

At what scale do viruses generally fall within the range of measurement?

Nanometer to micrometer range Signup and view all the answers

What do microbes, including viruses and bacteria, have in common?

They all require a microscope to be observed Signup and view all the answers

Which aspect of microbes can potentially affect patient safety?

Their potential to spoil pharmaceutical products Signup and view all the answers

What is the primary role of a gelling agent in solid media formulas?

To create a solid structure for the culture Signup and view all the answers

Which type of microorganism can survive only in the presence of oxygen?

Obligate aerobe Signup and view all the answers

Which of the following is NOT a characteristic of obligate anaerobes?

They require oxygen for metabolism Signup and view all the answers

What pH range is typically maintained for solid media focused on neutral growth?

pH 7.5-8.0 Signup and view all the answers

Which method can be used for cultivating anaerobic microorganisms?

Sealed anaerobic jars Signup and view all the answers

What characteristic distinguishes Gram negative bacteria from Gram positive bacteria?

Gram negative possess a thinner peptidoglycan layer. Signup and view all the answers

How thick is the peptidoglycan layer in Gram positive cells compared to Gram negative cells?

Thicker than Gram negative. Signup and view all the answers

Which of the following statements about the cell membrane structure of Gram positive and Gram negative bacteria is true?

Gram negative cells have two plasma membranes. Signup and view all the answers

Which factor allows the peptidoglycan layer to permit particles up to ~2nm to pass through?

Porosity of the peptidoglycan layer. Signup and view all the answers

What percentage of cell weight does the peptidoglycan layer constitute in Gram positive bacteria?

Around 90% Signup and view all the answers

What is the function of the outer membrane in Gram negative bacteria?

Serves as a barrier to certain antibiotics. Signup and view all the answers

Which component is directly attached to NAM (N-acetylmuramic acid) in the structure of Gram negative bacteria?

A chain of amino acids. Signup and view all the answers

When comparing Gram positive and Gram negative bacteria, which is an accurate observation regarding their membranes?

Gram positive have a single plasma membrane. Signup and view all the answers

What role does the periplasmic space play in Gram negative bacteria?

It contains metabolic enzymes and transport proteins. Signup and view all the answers

Which antibiotic type might be effective against Gram negative bacteria?

Antibiotics that disrupt protein synthesis. Signup and view all the answers

What defines a serotype within a species?

Distinct variations in cell surface antigens Signup and view all the answers

Which of the following best describes genotype classification?

Part of the genetic makeup determining characteristics Signup and view all the answers

Which method is used in phylogenetics for studying evolutionary relationships?

16S rRNA sequencing Signup and view all the answers

What is true about thermophiles and psychrophiles?

Thermophiles thrive in high temperatures while psychrophiles thrive in cold. Signup and view all the answers

Which of the following statements is correct regarding whole genome sequencing?

It assesses the complete DNA sequence of an organism at a specific time. Signup and view all the answers

Which classification method provides the least detailed information?

Serotype classification Signup and view all the answers

What is a characteristic of vertical gene transfer?

It describes the passage of genetic information from parent to offspring. Signup and view all the answers

Which characteristic is used in phenotype classification?

Cell structure determined by Gram staining Signup and view all the answers

Which term describes observable characteristics of an organism?

Phenotype Signup and view all the answers

How many serotypes does the Salmonella genus host?

Over 2600 Signup and view all the answers

Study Notes

Microbiology Textbooks

Key microbiology textbooks include Prescott's Microbiology (8th ed.) by Willey et al., published by McGraw-Hill Higher Education; Brock Biology of Microorganisms (14th ed.) by Madigan et al., published by Pearson; Hugo & Russell's Pharmaceutical Microbiology (8th ed.) by Denyer et al., published by Blackwell; and Russell, Hugo & Ayliffe's Principles and Practice of Disinfection, Preservation and Sterilization (5th ed.) by Fraise et al., published by Wiley-Blackwell.

Learning Objectives

Gain understanding of basic microbiology principles, including definitions of microbiology and microorganisms, and methods for studying microbes.
Understand the importance of microbiology in areas like human health & wellbeing and pharmaceuticals/biotechnology.

What is Microbiology?

Microbiology is the study of microorganisms (microbes).
Microbes include bacteria, viruses, fungi, archaea, parasites, and protozoa.
Microbiology has significant impact on various fields, such as food production, sewage treatment, agriculture, disease study, pharmaceuticals and biotechnology.

What are Microbes?

Microorganisms (microbes) are microscopic (<1 mm) and often unicellular.
Viruses are acellular.
Fungi can form multicellular structures.
Microbes are present in nearly every environment.
The first organisms on earth.
Greatest genetic diversity.
Microbes outnumber human cells by a great margin.

Top causes of death in UK

Data shows changes in top causes of death in the UK between 1915 and 2015. Infectious diseases were a more significant cause; notable declines in infectious diseases due to medicinal advances like the invention of Penicillin.

Microbes and Health

Not all microbes are harmless. Some microbes can cause serious diseases and infections.
Microbes play a role in non-infectious diseases, like stomach ulcers and obesity.
Some types of bacteria can be beneficial or commensal.
Examples of harmful bacteria include E. coli O157:H7. Examples of beneficial bacteria include E. coli Nissle 1917.

Normal Flora

Normal flora are organisms that live in a benign symbiotic relationship with their host.
Example of normal flora is E. coli.
These microbes can be important in preventing infection.
If conditions change (e.g. immune deficiency, stress, hormonal changes, environmental changes), they may overgrow and cause infections.

Challenges in Medical Microbiology

Antibiotic resistance is a significant concern.
Misuse of antibiotics has accelerated the development of resistance.
Antimicrobial resistance is estimated to lead to millions of deaths per year.

Microbiology in Biotechnology and Industry

Biotechnology is a broad field that uses living organisms/systems to produce products.
Developments in molecular biology have expanded the scope of biotechnology.
Industrial use of microbes in biotechnology produces many compounds including insulin and antibiotics.

Biotechnology: Industrial chemicals

Microbes, like Aspergillus niger, can produce industrial chemicals such as citric acid.
Proteases from Bacillus licheniformis are used in laundry detergents.

Biotechnology: Natural medicinal products

Natural products of microbial origin have wide use in therapeutics, including antimicrobials, cholesterol lowering agents, and neurotoxins (e.g. botulinum toxin).

Biotechnology: Recombinant medical products

Bacteria can be genetically modified to produce therapeutic proteins.
Recombinant human insulin (Humulin) is an example.
Recombinant vaccines (e.g., Gardasil) can target human papillomavirus (HPV).

Microbial Spoilage

Microbes often spoil products by utilizing nutrients, leading to deterioration of the product.
This can affect pharmaceutical products, targeting raw materials or finished products, causing costs/risks.

Practical microbiology: Growing microbes

Sterile or liquid media used to grow microbes in the laboratory.

Practical microbiology: Looking at microbes

Different methods exist for visualizing microorganisms, including the naked eye, and microscopic approaches like light microscopy and electron microscopy.

Practical microbiology: Molecular microbiology

Extract genetic components (DNA, RNA) for whole genome sequencing.
Analyze cell components (proteins) for immunological and structural studies.

Classification of Biological entities

Classification systems categorize organisms based on shared characteristics.
Organisms are classified into cellular and acellular categories (e.g. Eukarya, Archaea, Bacteria; Viruses, Viroids, Virusoids, Prions).

Taxonomy ranks: Species

Species are groups of organisms with stable, shared properties, distinct from other groups.
Strains are subtypes of a species that differ slightly in characteristics.

Phenotype classification in microbiology

Morphology (shape, cell structure)
Biochemistry (enzyme production, transport proteins)
Life cycle (vegetative or spore forming)

Serotype classification in microbiology

Serotype refers to distinct variations in cell surface antigens within a species. This is often characterized using different identifying antigens (e.g. Kauffman-White classification).

Genotype classification in microbiology

Genotype refers to a cell's genetic makeup, determining characteristics.
Genomics (DNA sequencing) can be used to determine this.
Bacterial species definition uses genomic sequencing with at least 95% identical genomic sequences to determine species. This method is affected by horizontal gene transfer.

Whole genome sequencing

Determining the complete DNA sequence of an organism at a single time.
Information such as presence/absence of genes, gene mutations or insertions/deletions can then be used to characterize and assess organisms. (e.g. SNP, RNA) phylogenetic analysis, etc.

Visualizing Genotypes: Phylogenetics

Phylogenetics studies evolutionary relationships using DNA or protein similarities.
MSA generates clusters of related organisms and phylogenetic trees from this data to show the relationships between species.

How to work with dangerous bugs and not catch something

Microbiology practice necessitates strict adherence to Biosafety Levels (BSLs) to avoid contamination.
Understanding ACDP categories and Biosafety levels is essential for safe handling of microbiological specimens.

Microbial growth and evolution

How microbes are cultured.
Different stages of bacterial and viral growth (lag, log, stationary, and death phases).
Introduction of bacterial evolution and its relevance.

Sources of carbon, energy and electrons

Microbes require carbon and energy sources for growth and metabolism. Examples of these could include CO2 (used by autotrophs); light (used by phototrophs), compounds, reduced inorganic compounds (used by lithotrophs), organic molecules (used by organotrophs) etc.

In-vitro microorganism culture

Culturing microbes in a controlled environment outside of their natural habitat (e.g., liquid or solid media)
The type of media used can determine which microbes grow.

Atmospheric requirements

Microbes require specific atmospheric environments for growth.
Examples include obligate aerobes (require oxygen), obligate anaerobes (require absence of oxygen), facultative aerobes (can adapt without oxygen), microaerophiles (need lower oxygen levels) and aerotolerant anaerobes (tolerate oxygen but use fermentation for growth)

Bacterial cell division and growth

Bacteria can reproduce independently via binary fission or budding.
Growth proceeds through phases like lag, log, stationary and death. Doubling time differs widely amongst species.

Microbial metabolism

Primary metabolism involved in central processes such as synthesis of cellular components and energy production
Secondary metabolism involved in production of non-essential (but beneficial) byproducts such as antibiotics

Laboratory scale culture

Different culture methods are used dependent on the requirements of the product/requirements to conduct the tests (e.g. batch culture, continuous culture).

Viral replication

Viral replication relies on the subversion of host replication machinery
Lytic vs lysogenic replication mechanisms.

Viral replication - types

Viral replication can be in two ways, Lytic and Lysogenic.

Bacterial evolution: Mutation

Mutations are permanent changes in a cell's genetic material.
Mutations can be harmful, beneficial or neutral to the cell.

Bacterial evolution: DNA acquisition

Bacteria can acquire new genetic material through horizontal gene transfer via several mechanisms (transformation, transduction and conjugation).

Bacterial evolution: Antimicrobial resistance

Antibiotic usage can lead to selective pressure on bacteria, potentially accelerating the evolution of resistant strains.

Why should I care?: Antimicrobial resistance

Antibiotic resistance is a serious issue requiring concern due to its potential health risks and implications for healthcare systems. The emergence of drug resistance is a serious concern around the world.

Strain improvement

Improving bacterial strains to increase production yields/efficiency (e.g. Penicillium chrysogenum) is done in many ways including genetic manipulation, exposing to stressors etc.

Heterologous Gene Expression

Using organisms (e.g., bacteria) to produce a product that is not naturally produced

Sources of Contamination and Sampling

Sources of microbial contamination can include environmental sources and personnel.

Controlling Microbial Contamination

Environmental/Personnel controls reducing the risk of contamination by using methods such as clean rooms, laminar flow cabinets, isolators and PPE, hand washing/disinfection, to avoid contamination.

Aseptic Technique

Aseptic techniques are used in sterile medicinal products
Aseptic techniques are extremely critical to minimize contamination

Microbial sampling

Filtration and direct inoculation for isolating samples. Environmental sampling (surface, contact, air)

Microbiological calculations: Total viable count

Use haemocytometer or other methods for counting microbes
Useful for determining numbers of microbes or CFUs in a known area

Regulating Contamination

Regulatory agencies ensure safety & quality standards in the manufacturing through testing/regulations of products to minimize/detect contamination.

What happens when it all goes wrong?

Microbial contamination of products can result in product recalls and litigation.

MPharm Programme

Purification section: focus on different purification method(s), downstream procedures, sterilisation and sterility checking of products/procedures.

Microbial Identification

Techniques (culture-based and molecular) for identifying microbial contaminants, limitations & advantages.

What is Diagnostic Microbiology?

Diagnostic microbiology emphasizes identifying the source/cause of infection. This can involve a range of tests and techniques from typing, testing antimicrobials to examining the cells/genotype etc.

Microscopy: Light and Electron Microscopy

Methods for visualizing microorganisms, using light microscopy (standard staining procedures e.g Gram stains) or electron microscopy.

Molecular Identification: PCR, ELISA, MALDI TOF

Identification of microbes using various molecular techniques (e.g., PCR, ELISA), MALDI-TOF mass spectrometry.

Disease and Pathogenesis

Infectious diseases still represent a significant public health problem.
Factors for risk of developing infectious disease include exposure, age, genetics, etc.

Scale of disease

Endemic, epidemic and pandemic infectious disease outbreak types exist with varied levels of associated risk

Sources of Disease

Sources of infectious diseases can include environmental contaminants (water, aerosolized pathogens, soil), animal sources, or other personnel.

Terminology

Definitions of key terms in infectious diseases including pathogenicity, virulence, and virulence factors, also related concepts relating to microbial infections (e.g. colonization, transmission, immuno-evasion), and others.

Transmission and exposure

Methods of microbial transmission, including vertical (mother to child), horizontal (person to person), and vector (through other organisms).
Aspects of exposure including the role of microbes and factors that effect their persistence (e.g. host, environmental, etc..)

Biofilms

Biofilms are complex communities of microbes which adhere to a surface, leading to increased resistance to treatment and other problems
Biofilm forming organisms are prevalent, and problematic

Microbial toxins

Classification of microbial toxins, including exotoxins and endotoxins (e.g. botulinum toxin), the different effects of toxins (e.g. cell death), and how they may affect the host response (e.g. septic shock).
Different types of microbial exotoxins are mentioned (e.g. cytotoxins, neurotoxins & enterotoxins), their mode of action & effects on the host.
Endotoxins (e.g. LPS) are also mentioned, their properties, host response, and issues around their removal/detection.

Non-bacterial disease

Diseases caused by fungi (e.g. athletes foot, thrush, aspergillosis) and viruses discussed.

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Test your knowledge on the fundamental concepts of microbiology, including the roles of microorganisms, important textbooks, and associated areas of study. This quiz covers essential topics such as the composition of vaccines and laboratory techniques in microbiology. Perfect for students or anyone interested in the field!