Microbiology: Normal Flora vs. Pathogens

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Questions and Answers

How do normal flora interfere with the growth of pathogens?

By competing for nutrients and producing substances that inhibit pathogen growth

What is contamination?

The presence of microorganisms on a living or non-living surface

What is the difference between infection and disease?

Infection occurs when microorganisms multiply in the host, while disease is the resulting harm or malfunction of the organ or body

What is pathogenicity?

The ability of a microorganism to produce disease Signup and view all the answers

What is the difference between pathogenicity and virulence?

Pathogenicity is the ability to produce disease, while virulence is the intensity of the disease produced Signup and view all the answers

What is an example of a microorganism with high virulence?

Mycobacteria tuberculosis Signup and view all the answers

What is colonization?

The multiplication of microorganisms in or on the host body without inducing harmful effects Signup and view all the answers

What is the relationship between contamination, colonization, and infection?

Contamination can lead to colonization, which can lead to infection Signup and view all the answers

What is an opportunity for an organism to cause disease, especially when the host's defenses are weakened?

Failure of host defenses, e.g. AIDS Signup and view all the answers

What can happen when normal microflora is disrupted, leading to an imbalance in the body's natural ecosystem?

Yeast growth due to inhibition of normal flora by antibiotics Signup and view all the answers

What is the difference between infectious and non-infectious diseases?

Infectious diseases are caused by infectious agents, while non-infectious diseases are caused by any factor other than infectious agents Signup and view all the answers

What is an example of a non-communicable infectious disease?

Infection by organisms in the environment, e.g. Tetanus Signup and view all the answers

What is the main difference between communicable and non-communicable infectious diseases?

Communicable diseases can be transmitted from one host to another, while non-communicable diseases cannot Signup and view all the answers

What is an example of a disease caused by an error in genetic information?

Inherited diseases Signup and view all the answers

What is the term for a relationship between organisms where one benefits and the other is harmed?

Parasitism Signup and view all the answers

What is the term for a relationship between organisms where one benefits and the other is not affected?

Commensalism Signup and view all the answers

What is the incubation period in the context of infections?

The time between infection and the appearance of signs and symptoms, ranging from a few days to months or years. Signup and view all the answers

What is the prodromal phase of infection?

A short period where non-specific symptoms appear. Signup and view all the answers

What characterizes the acme of an infection?

The peak of the infection, often marked by fever due to the release of pyrogens. Signup and view all the answers

What is the purpose of the convalescence period?

A recovery phase where symptoms disappear, and the body heals and regains strength. Signup and view all the answers

What are sequelae, and how do they relate to infections?

Sequelae are long-term effects or complications that can occur after an infection, such as blindness or organ damage. Signup and view all the answers

What is a communicable disease, and when can it be transferred?

A communicable disease can be transferred during the incubation period and during recovery from the disease. Signup and view all the answers

What is the key difference between infection and disease?

Infection refers to the presence of a pathogen, while disease refers to the symptoms and harm caused by the pathogen. Signup and view all the answers

What is the significance of the decline phase in the stages of infection?

The decline phase marks the point where host defenses and treatments overcome the pathogen, and symptoms are reduced. Signup and view all the answers

Study Notes

Normal Flora and Pathogens

Normal flora interfere with pathogen growth by competing for nutrients or producing substances that inhibit pathogen growth.

Contamination, Infection, and Disease

Contamination: the presence of microorganisms on a living or non-living surface.
Colonization: the multiplication of microorganisms on or in the host body without inducing harmful effects.
Infection: the induction of destructive or harmful effects on host tissue as a result of microorganism multiplication in or invasion of that tissue.
Disease: a disturbance in the health of the organ/body leading to its malfunction.
The progression from contamination to colonization to infection can lead to disease.

Pathogenicity and Virulence

Pathogenicity: the ability of an organism to produce a disease, dependent on its ability to invade the host, multiply, and avoid host defenses.
Virulence: determines the intensity of disease produced by the pathogen.
Virulence can increase due to factors such as failure of host defenses, introduction of the organism into unusual body sites, or disruption of normal microflora.

Kinds of Diseases

Infectious diseases: caused by infectious agents (e.g., bacteria, viruses, fungi, protozoa, and helminths).
Non-infectious diseases: caused by any factor other than infectious agents.
Communicable infectious diseases: can be transmitted from one host to another (e.g., influenza, measles).
Non-communicable infectious diseases: not transferred from a host to another, can result from infections by normal flora, ingestion of food poisoned by bacterial toxins, or infection by environmental organisms.

Classification of Diseases

Inherited diseases: caused by errors in genetic information.
Congenital diseases: present at birth (e.g., poliovirus leaving paralysis, some diseases leaving scars).

Stages of Infection

Incubation period: the time between infection and appearance of signs and symptoms, during which the patient is contagious.
Prodromal phase: a short period with non-specific symptoms, during which the patient is contagious.
Invasive phase: full development of signs and symptoms, during which the patient is contagious.
Decline phase: host defenses and treatments overcome the pathogen, symptoms are reduced, and the body functions gradually return to normal.
Convalescence period: the recovery phase, during which symptoms disappear, and the body heals and regains strength.

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Description

This quiz explores the role of normal flora in preventing the growth of pathogens, including competing for nutrients and producing inhibitory substances. It also covers contamination, infection, and disease.