Microbiology Exam 1 Study Guide

Steps of the scientific method

1. Make an observation
2. Ask a question
3. Hypothesis
4. Test Hypothesis
5. Analyze Results
6. Report Results

List and describe the rules of science

1. Science is guided by natural laws
2. Science has to be explained by reference to natural law
3. Science is testable against the empirical world
4. Sciences conclusions are tentative
5. Science is falsifiable

Define Theory

A well-substained explanation of some aspect of the natural world

Define Law

A descriptive generalization of how some aspects of the natural world behaves under stated circumstances

Define Hypothesis

A tentative statement about the natural world leading to deductions that can be tested

Define Fact

An observation that has been repeatedly confirmed and is considered “true”

Microbiology

The study of living organisms that are very small

Taxonomy

The science of classification

Phylogeny

The study of the evolutionary history of a group of organisms

Prokaryotic species

No nucleus; No membrane bound organelles

Eukaryotic species

Nucleus; Membrane bound organelles

Why is the study of microbiology important?

1. To treat diseases caused by microbes
2. Food production/packing
3. Prevent infections caused by microbes

How are all living things alike?

1. Organized
2. ATP
3. Homeostasis
4. Reproduces
5. Evolves
6. Genetic Material

How did Aristotle classify organisms?

Plant or Animal

How did Linnaeus classify organsims?

Scientific names and kingdoms

Whittaker’s 5 Kingdom System of Classification

1. Prokaryote
2. Protista
3. Fungi
4. Plantae
5. Animalia

Woese’s Three Domain System of Classification

1. Bacteria
2. Archea
3. Eukarya

According to the 5 Kingdom System bacteria is classified as

Prokaryote

The basis for Woese to classify organisms in the Three Domain System

rRNA differences

What is a ribosome?

1. Site of protein synthesis
2. Composed of RNA and Protein

Why are ribosomes important in studying phylogeny?

RNA is very similar in all cells so differences rRNA stand out

Endosymbiotic Theory

States that eukaryotes are a product of one prokaryotic cell engulfing another and eventually evolving over time until a new type of cell emerged (mitochondria, chloroplasts)

Rules of scientific nomenclature

1. Genus name is capitalized
2. Species is not capitalized
3. Genus and Species are italicized or underlined
4. Name usually tells you something about organism

Manual used to identify bacterial species

Bergey’s Manual

Robert Hooke

1. First to use the term cell
2. Observed cork under a microscope

van Leeuwenhoek

Credited as the first person to have created a microscope powerful enough to see microbes - coined “animalcules”

Spontaneous Generation

Notion that life can arise from non-living matter

Francesco Redi

3 Jars to prove that maggots do not spontaneously generate from the meat, flies lay eggs

Spallanzani

Heated broth contains no living microbes, if introduced to air there was growth, so microbes were introduced through the air

Louis Pasteur

Concluded that there were airborne microorganisms that were responsible for bacterial growth

What else did Pasteur’s experiment contribute to the study of microbiology?

Life only comes from life

Theory of Biogenesis

All cells arise from pre-existing cells

Fracastoro

Proposed that seed-like spores may be transferred between individuals through direct contact, exposure to contaminated clothing, or through the air

Semmelweis

* Puerperal fever and child birth


* Washing hands can prevent the spread of disease

Lister

Phenol spray disinfectant during surgery to reduce post surgical infection

Koch (postulates)

A specific disease could be attributed to a specific microbe

Chinese Healers (did?)

Variolation - deliberate inoculation of individuals with infectious materials from small pox victims

Jenner

Exposure to a less virulent pathogen could provide immune protection against a more virulent pathogen - cowpox→small pox

Ehrlich

* Developed Salvarsan to cure syphilis
* Set out to synthesize chemical compound capable of killing infectious microbes without harming patient

Flemming

Accidentally discovered penicillin

Pathology

The study of the causes and effects of disease or injury

Infection

The successful colonization of a host by a microorganism

Disease

Causes signs and symptoms resulting in a deviation from the normal structure or functioning of the host

Normal Microbiota (resident)

Microbes that constantly live in or on our bodies

Transient Bacteria

Microbes that are only temporarily found in the human body

Microbial Antagonism

Resident microbiota is important for health because they occupy the space that would otherwise be taken by pathogenic microorganisms “intestinal tract”

Opportunistic Pathogen

Resident microbiota that have become parasitic

Synergism

The different bacteria are helping each other

Mutualism

Benefitted/Benefitted

Neutralism

Unaffected/Unaffected

Commensalism

Benefitted/Unaffected

Sign of a disease

are objective and measurable and can be directly observed by a clinician

Symptoms of a disease

are subjective are felt or experienced by the patient, cannot be clinically confirmed

Communicable

capable of being spread from person to person through either direct or indirect mechanisms

Contagious

means that a disease is easily spread from person to person

Categories used to describe disease occurrence

Incidence and Prevalence

Incidence

number of population with disease

Prevalence

percentage of population currently with disease

Sporadic

occasional occurrence

Endemic

regular cases often occurring in a region

Epidemic

an unusually high number of cases in a region

Pandemic

a global epidemic

Local Infection

Confined to a small area of the bodyq

Focal Infection

Pathogen of the toxins it produces can spread to a secondary location

Systemic Infection

Infection becomes disseminated throughout the body

Primary Infection

Infection that is caused by one pathogen (initial infection)

Secondary Infection

Infection that was able to infect host due to a primary infection

Subclinical Infection

Infections that do not present any noticeable signs or symptoms

What are all the sources of infections (reservoirs)?

nonliving and living

What is a zoonoses?

non-human animal reservoir

What are there ways of contact transmission?

* Contact Transmission
* Indirect Contact Transmission
* Vehicle Transmission
* Vector Transmission

What is a Fomite?

Nonliving object that facilitates the indirect transmission of pathogens

What is vehicle transmission?

Transmission of pathogens through vehicles such as water, food, and air

What is a vector?

Diseases transmitted by a mechanical or biological vector carries the disease from one host to another on its body passively and is typically unaffected by the disease (mosquito, rats, etc.)

What is a healthcare associated infection?

Infection that is transmitted in the healthcare setting

Incubation Period

Infected

Prodromal Period

Begins to experience symptoms

Period of Illness

Symptoms are most severe

Period of Decline

Treatment begins to contain infection

Period of Convalescence

Return to normal functions

Emerging Infectious Disease (EID)

can occur when existing microbe becomes pathogenic

Factors that contribute to EID

Human Activity/ International Travel

Epidemiology

The study of disease in a population

Description of Leprosy

Nerve damage and skin lesions

Two forms of Leprosy

Tuberculoid and Lepromatous

Cause of Leprosy

*Mycobacterium leprae*

How is Leprosy transmitted?

* Long term contact
* Person to person
* Nasal discharge
* Respiratory droplets

How is the Leprosy bacteria grown?

Toe pads of armadillos or naked mice

How is Rabies transmitted?

Bite of a rabid animal

Symptoms of Rabies

* Flu-like
* Cerebral dysfunction, spasms, anxiety, confusion, agitation, hydrophobia

Causes of Rabies

*Rhabdoviridae lyssavirus*

Treatment of Rabies

* Washing the wound
* Immuneoglobin + PEP

Rabies Reservoirs

Dogs, Skunks, Raccoons

Where do you find rabies?

In rabid mammals

What are the three forms of the plague?

Bubonic, Pneumonic, Septicemic

Characteristics of the Bubonic Plague?

Large buboes from infected lymph nodes

Characteristics of the Pneumonic Plague?

Infection moves to the lungs

Characteristics of the Septicemic Plague?

Septic shock

What causes the plague?

*Yersinia pestis*

What is the vector and reservoir of the plague?

rat flea *Xenopsylla cheopis*