Microbiology II: Pathology, Infection, and Disease

A comprehensive set of flashcards covering key concepts from the lecture on Microbiology II, focusing on pathology, infection, and disease.

What is the scientific study of disease called?

Pathology.

What does pathogenicity refer to?

The ability to cause disease by overcoming the defenses of a host.

What is virulence?

The degree or extent of pathogenicity.

What is the difference between infection and disease?

Infection is the invasion or colonization of the body by pathogenic microorganisms; disease occurs when an infection results in any change from a state of health to an abnormal state.

What is inflammation?

A localized tissue response to injury or infection characterized by redness, swelling, pain, warmth, and an accumulation of phagocytic cells.

What factors determine the distribution and composition of the normal microbiota?

Nutrients, physical and chemical factors, mechanical factors, and host defenses.

What role does microbial antagonism play in normal microbiota?

It prevents the overgrowth of harmful microorganisms by competing for nutrients and producing substances harmful to invaders.

What is the relationship called between normal microbiota and the host?

Symbiosis.

What is commensalism?

A type of symbiotic relationship where one organism benefits, and the other is unaffected.

What is mutualism?

A type of symbiotic relationship where both organisms benefit.

What is parasitism?

A type of symbiotic relationship where one organism benefits at the expense of the other.

What are opportunistic pathogens?

Microorganisms that ordinarily do not cause disease in their normal habitat in a healthy person but may cause disease under certain conditions.

What are Koch's postulates?

Four criteria used to establish a causative relationship between a microbe and a disease.

What is the first postulate of Koch?

The pathogen must be isolated from the diseased host and grown in pure culture.

What is the second postulate of Koch?

The pathogen from the pure culture must cause the disease when inoculated into a healthy, susceptible laboratory animal.

What is the third postulate of Koch?

The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.

What is the fourth postulate of Koch?

The same pathogen must be present in every case of the disease.

What are some exceptions to Koch's postulates?

Some microbes have unique culture requirements, some pathogens cause infections only in humans, and some pathogens can cause several diseases.

What is transmission of microorganisms?

The process by which microbes are spread from one host to another.

What is a communicable disease?

A disease that spreads from one host to another.

What is a noncommunicable disease?

A disease that is not spread from one person to another.

What is endemic disease?

A disease that is constantly present in a population.

What is a pandemic disease?

A widespread epidemic disease that occurs worldwide.

What is herd immunity?

The resistance to the spread of a disease within a population due to a high proportion of immune individuals.

What is the incubation period?

The interval between the initial infection and the appearance of signs or symptoms.

What is the prodromal period?

A relatively short period that follows the incubation period characterized by early symptoms.

What is the period of illness?

The time during which the disease is most severe.

What is the period of decline?

The time during which signs and symptoms subside.

What is the period of convalescence?

The time during which the person regains strength and the body returns to its prediseased state.

What is contact transmission?

The spread of disease agents by direct contact, indirect contact, or droplet transmission.

What is vehicle transmission?

Transmission by a medium such as water, food, or air.

What are vectors?

Biological agents that transmit disease.

What are healthcare-associated infections (HAIs)?

Infections acquired as a result of a hospital stay.

What are emerging infectious diseases (EIDs)?

Diseases that are new or changing, showing an increase in incidence.

What does epidemiology study?

How diseases occur and how they are transmitted in populations.

What is morbidity?

The incidence of a specific notifiable disease.

What is mortality?

The deaths from notifiable diseases.

How do microorganisms enter a host?

They must gain access, adhere to host tissues, penetrate defenses, and damage tissues.

What is the parenteral route?

The route of entry beneath the skin or mucous membranes.

What are the portals of entry for pathogens?

Skin, mucous membranes, and parenteral routes.

What is ID50?

The infectious dose for 50% of a sample population.

What is LD50?

The lethal dose for 50% of a sample population.

What role do capsules play in virulence?

Capsules prevent phagocytosis by the host.

What is toxigenicity?

The capacity of microorganisms to produce toxins.

What are exotoxins?

Toxins produced within bacteria and secreted during their growth.

What are endotoxins?

Toxins that are part of the outer cell wall of gram-negative bacteria.

What is the function of A-B toxins?

They consist of an active part and a binding part to exert their effects.

What does hyaluronidase do?

It hydrolyzes hyaluronic acid, helping bacteria spread through tissues.

What is the significance of antigenic variation?

It allows pathogens to evade host immune responses.

How do bacteria damage host cells?

By using host's nutrients, causing direct damage, producing toxins, or inducing hypersensitivity.

What is the difference between bacteremia and septicemia?

Bacteremia is the presence of bacteria in the blood; septicemia is a more severe condition of blood poisoning due to multiplying pathogens.

What is viremia?

The presence of viruses in the blood.

What is toxemia?

The presence of toxins in the blood.

What is the importance of the preferred portal of entry?

It is necessary for many pathogens to cause disease.

What is microbial waste accumulation?

The harmful effects caused by the accumulation of microbial waste products.

What can lead to secondary infections?

When a primary infection weakens the body’s defenses.

What role does the immune response play in disease?

It can induce hypersensitivity reactions, which can damage host tissues.

What is the significance of fever in disease?

It is a common sign of infection and activates immune responses.

What are mechanical transmission methods by vectors?

Passive transport of pathogens on an insect's body parts.

What is biological transmission?

An active process where vectors actively transmit pathogens through their bites.

What are fomite examples?

Inanimate objects like tissues, utensils, and toys that can carry pathogens.

What disease is associated with E. coli O157:H7?

A pathogenic strain of E. coli that can cause severe foodborne illness.

What diseases are commonly contracted via the respiratory tract?

Common cold, pneumonia, tuberculosis, influenza, and measles.

What can cause chronic disease?

Diseases that develop more slowly and recur for long periods.

What is the definition of latent disease?

A disease where the causative agent remains inactive before becoming active.

What is the relationship between climate and disease incidence?

Climate and weather changes can influence the prevalence of respiratory diseases.

What is the role of mechanical factors in infections?

Mechanical actions like chewing and mucus help to flush out pathogens.

What is toxic inflammatory condition arising from the spread of microbes?

Sepsis.

What disease can arise from the alteration of the normal microbiota by antibiotics?

C. difficile infection leading to colitis.

What impact do antibiotics have on normal microbiota?

Antibiotics can eliminate normal flora, facilitating the growth of opportunistic pathogens.

What is an example of mutualism in normal microbiota?

E. coli in the large intestine synthesize vitamin K.

How do pathogens gain access to the body?

Through broken skin, mucous membranes, or direct deposition beneath the skin.

What pathogen is known for causing syphilis?

Treponema pallidum.

What is an example of a chronic disease?

Lyme disease.

What role does climate play in the incidence of respiratory diseases?

It increases during colder months.

Which microorganism is linked to opportunistic infections in AIDS patients?

Pneumocystis pneumonia.

What is an example of a sporadic disease?

Typhoid fever.

What is an example of a pandemic disease?

COVID-19.

What happens during the period of decline in disease?

Signs and symptoms subside, and recovery begins.

What is microbial antagonism?

Competition between normal microbiota and pathogenic microorganisms.

What do signs of a disease refer to?

Objective changes that can be observed and measured.

What factors may alter the course of a disease?

Predisposing factors such as gender, age, and genetic background.

What is a primary infection?

An acute infection that causes the initial illness.

What is a secondary infection?

A subsequent infection caused by an opportunistic pathogen after a primary infection.