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Questions and Answers
Which type of microorganisms cause infections with varying frequency and severity?
Which type of microorganisms cause infections with varying frequency and severity?
What is the term for microorganisms that are frequently found colonizing various body sites in healthy individuals?
What is the term for microorganisms that are frequently found colonizing various body sites in healthy individuals?
What happens when microorganisms establish themselves in a host without manifestation of symptoms?
What happens when microorganisms establish themselves in a host without manifestation of symptoms?
What is the term for the presence of microorganisms for a short period without damage or invasion?
What is the term for the presence of microorganisms for a short period without damage or invasion?
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What is the role of microorganisms in human health and disease?
What is the role of microorganisms in human health and disease?
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What is the term for microorganisms that have an established niche at one of the many body sites, which they occupy indefinitely?
What is the term for microorganisms that have an established niche at one of the many body sites, which they occupy indefinitely?
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What can microorganisms do to exist with other colonizing organisms and to inhibit competing intruders?
What can microorganisms do to exist with other colonizing organisms and to inhibit competing intruders?
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What is the term for the ability of microorganisms to cause disease with varying frequency and severity?
What is the term for the ability of microorganisms to cause disease with varying frequency and severity?
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What is the term for the site where an organism or pathogen lives and multiplies?
What is the term for the site where an organism or pathogen lives and multiplies?
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Which of the following is an example of a source that is not the same as the reservoir?
Which of the following is an example of a source that is not the same as the reservoir?
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What is the term for the damage or invasion of host tissues by organisms?
What is the term for the damage or invasion of host tissues by organisms?
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What is the term for a sudden increase in the number of cases of a disease in a population?
What is the term for a sudden increase in the number of cases of a disease in a population?
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Which of the following is an example of a pathogen that can cause life-threatening infections?
Which of the following is an example of a pathogen that can cause life-threatening infections?
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What is the term for the worldwide spread of a new disease?
What is the term for the worldwide spread of a new disease?
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What is the ability of an organism to cause disease in a susceptible individual?
What is the ability of an organism to cause disease in a susceptible individual?
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What type of pathogens cause infections in patients with normal immunity?
What type of pathogens cause infections in patients with normal immunity?
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What is the main function of lactoferrin in the host's defense against infection?
What is the main function of lactoferrin in the host's defense against infection?
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What is the term used to describe the ability of a microbe to adapt to a new environment and grow in tissues?
What is the term used to describe the ability of a microbe to adapt to a new environment and grow in tissues?
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What is the role of fimbriae (pili) in bacterial pathogenesis?
What is the role of fimbriae (pili) in bacterial pathogenesis?
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What is the primary function of secretory antibody in the host's defense against infection?
What is the primary function of secretory antibody in the host's defense against infection?
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What is the term used to describe the spread of microorganisms to distant sites?
What is the term used to describe the spread of microorganisms to distant sites?
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What is the role of polysaccharide capsule in bacterial evasion of the immune system?
What is the role of polysaccharide capsule in bacterial evasion of the immune system?
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Study Notes
Microorganisms
- Must take over the machinery of another living cell (eukaryote/prokaryote) to replicate
- Bacteria have a cell wall but lack eukaryotic organelles
- Fungi are eukaryotic with a rigid external wall, similar to plants
- Parasites exist as single or multicellular structures with eukaryotic cell plan
Introduction to Microbiology
- Study of micro-organism interaction with human host resulting in disease
- Resultant diseases are termed infectious diseases
- Micro-organism = BUG, Host = MUG, Antibiotic = DRUG
- Normal presence of micro-organisms on or in humans, with 10x more microbial cells than human cells
- Microorganisms play a role in both human health and disease
Microorganisms' Roles
- Commensal/Normal flora
- Degeneration of organic matter
- Biotechnological areas – medicines, vaccines
- Production of cheese, yogurt, beer, and wine
Definitions
- Commensal organisms = Normal flora = Microbiota
- Residents: strains that occupy a niche at a body site indefinitely
- Transients: acquired from environment, establish briefly, but are excluded by competition or host defense
- Pathogens: microorganisms that possess the ability to cause infections
- Contamination: presence of micro-organisms for a short period without damage or invasion
- Colonization: continued presence of organisms for long periods without causing damage or invasion
- Contagious: can spread between people
- Carrier state: pathogenic organisms establish themselves in a host without symptoms, and can transmit the infection
- Reservoir: where the organism/pathogen lives & multiplies (e.g. humans, animals, soil, water)
- Source: site from which the organism/pathogen spreads to the host (e.g. soil, contaminated vegetables)
Infection and Disease
- Infection: damage or invasion of host tissues by organisms
- Occurs with primary/professional pathogens or opportunistic pathogens
- Can be life-threatening, but many are treatable with anti-infective agents
- Prevention is possible for many infectious diseases with vaccines
- Epidemics: increase in the number of cases of a disease above what is normally expected
- Pandemics: worldwide spread of a new disease
Pathogenicity
- Pathogenicity: ability of an organism to cause disease in a susceptible individual
- Pathogens may be primary/professional or opportunistic
- Virulence: degree of damage caused by a microbe to its host
- Multiple virulent factors are required for an organism to attach, persist, cause disease, and escape
Virulence Factors
- Attachment/adherence and persistence
- Involves specialized surface molecules/structures that correspond to receptors on human cells
- Secretory antibody, lactoferrin, and lysozyme produced by the host as a way to protect against infection
- Lactoferrin competes with bacteria for free iron
- Adhesions: fimbriae (pili), surface polysaccharides
Invasion and Evasion
- Invasion into or beyond the surface mucosal cells
- Ability to penetrate and grow in tissues
- May be localized or involve deep tissues
- Invading organisms should be able to adapt to the new environment
- Evasion of the immune system: phagocytosis evasion, phagocytic cell killing, inhibit activation of complement pathway, polysaccharide capsule/protein A/leukocidins
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Description
This quiz covers the characteristics of different cell types, including eukaryotes and prokaryotes, and the biology of parasites.
