Microbiology Chapter 14

Questions and Answers

What is pathology?

Scientific study of disease - concerned with etiology (cause) and pathogenesis (development) & effects of disease.

Name 3 types of symbiotic relationships.

Mutualism, commensalism, parasitism.

What is mutualism?

Both organisms benefit from the relationship.

What is commensalism?

One organism benefits from the relationship and the other neither benefits nor is harmed. Signup and view all the answers

What is parasitism?

One organism benefits and one is harmed. Signup and view all the answers

Name 2 examples of mutualism.

Trichonympha in termite intestine and vitamin synthesizing bacteria in colon. Signup and view all the answers

Name an example of commensalism.

Staphylococcus sp. on human skin. Signup and view all the answers

Define disease.

Any change from a state of health. A disease may, but not always, result from infection. Signup and view all the answers

What are normal microbiota?

Organisms that colonize body surfaces without causing disease. Signup and view all the answers

What are transient microbiota?

Present for a few days/weeks, are easier to get rid of than normal flora. Signup and view all the answers

Where are resident microbiota found?

On skin, mucous membranes of digestive tract, upper respiratory tract, and distal part of urethra and vagina. Signup and view all the answers

Most resident microbiota are ______.

Commensal. Signup and view all the answers

Where are transient microbiota found?

On skin, mucous membranes of digestive tract, upper respiratory tract, and distal part of urethra and vagina. Signup and view all the answers

Why can't transient microbiota persist in the body?

Competition from other microorganisms, elimination by body's defense cells, chemical or physical changes in the body. Signup and view all the answers

When does normal microbiota develop?

In the birthing process. Signup and view all the answers

When is resident microbiota established?

First months of life. Signup and view all the answers

What are opportunistic pathogens?

Normal microbiota or harmless microbes that can cause disease under certain circumstances. Signup and view all the answers

Name 3 conditions that provide opportunities for pathogens.

Immune suppression, reduction in microbial antagonism, introduction of normal microbiota into unusual site in the body. Signup and view all the answers

Name an example of normal microbiota in unusual site.

E. coli in urethra causing UTI. Signup and view all the answers

Name 4 portals of pathogen entry.

Skin, mucous membranes, placenta, and parenteral route. Signup and view all the answers

What is the parental route?

Deposition directly into tissues under the skin or mucous membranes. Signup and view all the answers

Name some ways pathogens enter by parenteral route.

Punctures, cuts, deep abrasions, and surgery. Signup and view all the answers

What is adhesion?

Process by which microorganisms attach themselves to cells. Signup and view all the answers

Is adhesion required to successfully establish colonies within a host?

True Signup and view all the answers

Name adhesion factors.

Specialized structures, adhesins, and attachment proteins. Signup and view all the answers

Where are adhesion discs found?

Some protozoans. Signup and view all the answers

Where are hooks and suckers found?

In some helminths aka worms. Signup and view all the answers

Where are adhesins found?

In bacteria. Signup and view all the answers

Where are attachment proteins found?

Viruses. Signup and view all the answers

What are ligands?

Surface lipoproteins and glycoproteins that enable bacteria and viruses to bind to complementary receptors on host cells. Signup and view all the answers

What is avirulent?

False Signup and view all the answers

What is disease also referred to as?

Morbidity. Signup and view all the answers

What are asymptomatic infections?

Lack of symptoms but may still have signs of infection. Signup and view all the answers

What is etiology?

Study of the cause of disease. Signup and view all the answers

Who developed a set of postulates that must be satisfied to prove a particular pathogen causes a particular disease?

Robert Koch. Signup and view all the answers

Name 2 difficulties in satisfying Koch's postulates.

Diseases that can be caused by more than one pathogen, pathogens that are ignored as potential causes of disease. Signup and view all the answers

Name 3 diseases that can be caused by more than one pathogen.

Pneumonia, meningitis, and hepatitis. Signup and view all the answers

What is virulence?

Degree of pathogenicity. Signup and view all the answers

Name 5 virulence factors.

Adhesion factors, biofilms, extracellular enzymes, toxins, and antiphagocytic factors. Signup and view all the answers

What are extracellular enzymes?

Enzymes secreted by the pathogen that dissolve structural chemicals in the body and help the pathogen maintain infection, invade further, and avoid body defenses. Signup and view all the answers

What is hyaluronidase?

Extracellular enzyme that breaks down hyaluronic acid which holds animal cells together. Signup and view all the answers

What is collagenase?

Extracellular enzyme that digests collagen. Signup and view all the answers

What is coagulase?

Extracellular enzyme that causes coagulation to surround bacteria and protect them from body defenses. Signup and view all the answers

What are kinases?

Extracellular enzymes that break up blood clots, enabling bacteria to spread. Signup and view all the answers

Name 2 types of toxins.

Exotoxins and endotoxins. Signup and view all the answers

What are exotoxins?

Proteins or peptides secreted by microorganisms that destroy host cells or interfere with their metabolism. Signup and view all the answers

Name 2 types of exotoxins.

Cytotoxins and neurotoxins. Signup and view all the answers

What are cytotoxins?

Kill host cells or impair their ability to function. Signup and view all the answers

What are neurotoxins?

Adversely affect nerve cell function. Signup and view all the answers

Name 2 pathogens that secrete neurotoxins.

Clostridium tetani and Clostridium botulinum. Signup and view all the answers

What are enterotoxins?

Adversely affect cells lining the GI tract. Signup and view all the answers

Name 2 pathogens that secrete enterotoxins.

Staphylococcus aureus and Escherichia coli. Signup and view all the answers

What are endotoxins?

Lipid portion of lipopolysaccharide of outer membrane of gram-negative bacteria released when cells die. Signup and view all the answers

What are antitoxins?

Antibodies that bind to toxins and neutralize them. Signup and view all the answers

Name two factors that prevent phagocytosis by the host's phagocytic cells.

Bacterial capsule and antiphagocytic chemicals. Signup and view all the answers

How does a bacterial capsule stop phagocytosis?

Made up of chemicals found in the body so it is not recognized as foreign; also it is slippery. Signup and view all the answers

How do antiphagocytic chemicals stop phagocytosis?

Prevent fusion of lysosome and phagocytic vesicles to block digestion of microbe. Signup and view all the answers

What helps Streptococcus pyogenes resist phagocytosis?

M protein on cell walls and fimbriae. Signup and view all the answers

What are the five stages of infectious disease?

Incubation period, prodromal period, illness, decline, and convalescence. Signup and view all the answers

What is the incubation period?

Time between infection and appearance of first symptoms or signs of disease. Signup and view all the answers

What is the prodromal period?

Short time with only mild symptoms before illness. Signup and view all the answers

What is the illness stage?

Time of most severe symptoms and signs; host immune response not at its maximum. Signup and view all the answers

What is the decline stage?

Time when the immune response peaks and/or medical treatment overcomes pathogen. Signup and view all the answers

What is convalescence?

Time when the host recovers; tissues repaired and body begins to return to normal. Signup and view all the answers

Is the host usually infectious during all stages of disease?

True Signup and view all the answers

How does a pathogen leave the host?

By portals of exit; many of the same portals of entry. Signup and view all the answers

What are reservoirs of infection?

Sites where pathogens are maintained as a source of infection. Signup and view all the answers

Name 3 types of reservoirs.

Animal reservoirs, human carriers, and nonliving reservoirs. Signup and view all the answers

What are zoonoses?

Diseases that are naturally spread from their animal host to human host. Signup and view all the answers

Name 3 ways to acquire zoonoses.

Direct contact with animal or its waste, eating animals, and bloodsucking arthropods. Signup and view all the answers

What is infectious disease transmission?

Transmission from either a reservoir or from the host's portal of exit. Signup and view all the answers

Name 3 groups of infectious disease transmission.

Contact transmission, vehicle transmission, vector transmission. Signup and view all the answers

Name 3 categories of contact transmission.

Direct, indirect, and droplet transmission. Signup and view all the answers

What is direct contact transmission?

Person to person or animal reservoir to human. Signup and view all the answers

What is indirect contact transmission?

Pathogens spread from host to host by fomites. Signup and view all the answers

What are fomites?

Contaminated inanimate objects. Signup and view all the answers

What is droplet contact transmission?

Pathogens carried within respiratory droplets that exit the body by sneezing, coughing, and exhaling. Signup and view all the answers

How far do droplet transmissions travel?

Less than one meter. Signup and view all the answers

Name 3 types of vehicle transmission.

Airborne, water-borne, and food-borne transmission. Signup and view all the answers

What is airborne transmission?

Spread of pathogen to respiratory mucous membranes via aerosols. Signup and view all the answers

Name some airborne transmission pathogens.

Staphylococcus, Streptococcus, and Mycobacterium tuberculosis. Signup and view all the answers

What is water-borne transmission?

Spread of pathogen via contaminated water. Signup and view all the answers

Name some water-borne gastrointestinal diseases.

Cholera, giardiasis, amebic dysentery. Signup and view all the answers

What is food-borne transmission?

Spread of pathogens in or on food. Signup and view all the answers

Name 2 vector transmissions.

Biological and mechanical vectors. Signup and view all the answers

What are biological vectors?

Those that serve as a host for multiplication of the pathogen, as well as transmitting it. Signup and view all the answers

Name some examples of biological vectors.

Ticks, blood sucking flies, mites, lice, fleas. Signup and view all the answers

What are mechanical vectors?

Those that transmit pathogens passively by carrying them on their body parts. Signup and view all the answers

Name some examples of mechanical vectors.

Houseflies and cockroaches. Signup and view all the answers

What can houseflies and cockroaches carry?

Salmonella and Shigella. Signup and view all the answers

Name four methods of infectious disease classification.

Body system they affect, taxonomic groups of causative agent, longevity and severity, and how they are spread to a host. Signup and view all the answers

What is acute disease?

One that develops rapidly and lasts a short time; e.g., common cold. Signup and view all the answers

What is chronic disease?

One that develops slowly and lasts a long time; e.g., Hepatitis C, tuberculosis, leprosy, and mononucleosis. Signup and view all the answers

What is subacute disease?

One with a duration and severity between that of acute and chronic disease; e.g., subacute bacterial endocarditis. Signup and view all the answers

What is latent disease?

One that appears a long time after infection due to the inactivity of the pathogen; e.g., herpes infection. Signup and view all the answers

What is communicable disease?

One transmitted from an infected host directly or indirectly to another; e.g., influenza, herpes. Signup and view all the answers

What is noncommunicable disease?

One not spread from host to host; e.g., tetanus, botulism, acne, and tooth decay. Signup and view all the answers

What is primary infection?

Initial infection within the host. Signup and view all the answers

What is secondary infection?

One that follows primary infection, and may be caused by an opportunistic pathogen. Signup and view all the answers

What is epidemiology?

Study of where and when diseases occur and how they are transmitted within populations. Signup and view all the answers

Study Notes

Pathology and Disease

Pathology is the scientific study of disease, focusing on etiology (causes) and pathogenesis (development and effects).
Disease signifies any deviation from health; it may result from infection but is not always infectious.

Symbiotic Relationships

Three types of symbiotic relationships: mutualism (both organisms benefit), commensalism (one benefits, the other is unharmed), and parasitism (one benefits at the expense of the other).
Examples of mutualism include trichonympha in termite intestines and vitamin-synthesizing bacteria in the colon.
An example of commensalism is staphylococcus sp. found on human skin.

Microbiota

Normal microbiota are organisms that colonize the body without causing disease, e.g., Streptococcus in the mouth.
Transient microbiota are temporary residents that can be easily removed, e.g., microbes from door handles.
Resident microbiota develop during birth and are established within the first months of life, primarily found on skin and mucous membranes.
Most resident microbiota are commensal organisms, helping maintain body health.

Pathogen Entry and Adhesion

Pathogens enter the body through portals such as skin, mucous membranes, placenta, and the parenteral route (directly into tissues).
Adhesion is crucial for pathogens to establish colonies; it involves specialized structures like adhesins and various adhesion factors in viruses and bacteria.
Ligands are surface lipoproteins/glycoproteins that allow pathogens to bind to host cell receptors.

Virulence and Toxins

Virulence refers to the degree of pathogenicity, influenced by factors like adhesion, biofilms, toxins, and extracellular enzymes.
Toxins are classified into exotoxins (e.g., cytotoxins, neurotoxins) that destroy host cells or interfere with metabolism, and endotoxins released from gram-negative bacteria upon cell death.

Phagocytosis and Host Defense

Opportunistic pathogens can cause disease when conditions allow, such as immune suppression or introduction to unusual body sites.
Bacterial capsules and antiphagocytic chemicals can hinder phagocytosis by making pathogens less recognizable or preventing immune responses.

Stages of Infectious Disease

The five stages include incubation (time from infection to symptoms), prodromal (mild symptoms), illness (severe symptoms), decline (immune response peaks), and convalescence (recovery).
Hosts can be infectious during all disease stages.

Transmission and Reservoirs

Infectious diseases can be transmitted from reservoirs (sites where pathogens persist) through direct contact, vehicle transmission (airborne, waterborne, foodborne), and vector transmission (biological and mechanical).
Zoonoses are diseases that transfer from animals to humans via direct contact, consumption, or bites.

Disease Classification

Diseases are classified by affected body systems, taxonomic groups of causative agents, duration and severity, and modes of transmission.
Types of diseases include acute (rapid onset, short duration), chronic (slow onset, long duration), and latent (inactive pathogens reemerging later).

Infection Types

Primary infections are the initial infections within a host, while secondary infections follow due to opportunistic pathogens.

Epidemiology

Epidemiology is the study of disease occurrence, transmission, and patterns within populations, aiding in understanding and controlling disease spread.

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Explore the key concepts of Microbiology Chapter 14 through flashcards. This chapter focuses on pathology, types of symbiotic relationships, and their implications in disease. Perfect for students looking to reinforce their understanding of microbiological principles.