A patient who has recently undergone a total joint replacement surgery is given antibiotics prior to dental procedures.
A patient infected with HIV usually takes several different anti-HIV medications, including a reverse transcriptase inhibitor, one or more protease inhibitors, and an integrase inhibitor
Trimethoprim and sulfomethoxazole are often used together because they inhibit two successive steps in the folate biosynthetic pathway and this inhibition is greater than when either drug is used alone.
five primary modes of actions of antimicrobial drugs.
- cell wall synthesis
- cell membrane function
- protein synthesis
- nucleic acid synthesis
- metabolic pathways
choose the major challenge of antiviral therapy
Viruses rely on the metabolic system of the host cell.
select the three primary mechanisms by which antiviral medications work.
1 preventing entry of the virus into the host cell
2 blocking transcription and translation of viral proteins
3 preventing the maturation of viral particles
Please choose the term used to describe the type of antimicrobial resistance that is of most concern today.
select the three ways in which microorganisms acquire antimicrobial resistance.
1 - Spontaneous mutation
2 - Transfer of genes from other microorganisms
3 - Entering a dormant state in the presence of antibiotics, and resuming normal metabolic functions in the absence of antibiotics
select the five major mechanisms of antimicrobial resistance.
- Enzymatic inactiavtion of antibiotic
- Antibiotic efflux pumps get the antibiotic out of the cell
- Altered target site, such that the antibiotic can no longer bind to the target
- Microbe uses an alternative pathway to circumvent the blocked pathway
- Decreased permeability to the antibiotic
select the strategies that can be used to reduce the level of antimicrobial drug resistance
-prescribing antibiotics only for accurately diagnosed bacterial
-restricting use of newly developed antibiotics to those situations when the etiology can agent has been shown to be resistant to more traditional antibiotics
-limiting the use of antibiotics in animal feed
select the three major mechanisms by which antimicrobial resistance genes are shared and spread among microbial populations.
select the term that encompasses adverse responses to antimicrobial drugs such as hives, respiratory difficulties, and anaphylaxis.
choose the statement that best describes superinfection.
a secondary infection that occurs during antimicrobial therapy, caused by overgrowth of drug-resistant residents of the microbiota
choose the statement which best describes the goal(s) of antimicrobial susceptibility testing.
to determine which antimicrobial drug is most effective at inhibition of the causative agent
Please place the steps in the correct order to assess your knowledge of entry, establishment, and exit of infectious agents.
Carrier has infection but it is not apparent.
Carrier transmits infection before or after the period of symptoms.
incubation, chronic, convalescent
label the image to test your understanding of how communicable infectious diseases are acquired.
Please identify the four most significant interactions between humans and the microbes that live in and on our bodies.
-Microbes can protect and stabilize body surfaces on which they
establish themselves as normal residents
-Microbes promote the development and maturation of host immune defenses.
-Microbes may invade and grow in normally sterile body sites
-Microbes cause disease by damaging tissues and organs.
Please choose the statement that best describes the benefits of microbial antagonism to the human host.
Microbial antagonism occurs when members of the normal microbiota prevent pathogens from colonizing and becoming established in the body.
choose the statement that describes the initial acquisition and development of normal microbiota.
A newborn acquires normal microbiota during the birthing process and through contact with family, health care providers, food, and their environment.
Please order the following steps a microorganism takes in establishing an infection.
A(n) ______ pathogen causes disease in a healthy individual with a normal immune response, whereas a(n) ______ pathogen will not cause disease in a normal healthy host, but instead causes disease only when a host’s defenses are compromised in some way.
Select the body sites that serve as portals of entry for microbes
The minimum number of organisms necessary to enter through the portal of entry and establish infection is the ____________
select all of the specialized structures used by microorganisms to adhere to their host.
- slime layer
- capsid proteins
choose the best definition of virulence factors.
characteristics of a microorganism that enable it to establish infection and cause disease
select the factors below that contribute to a microorganism’s invasiveness.
- R factors
select characteristics exhibited by exotoxins, but not exhibited by endotoxins.
Require very small doses to cause toxic effects,
Have very specific targets,
Secreted from a living cell
1. appearance of first early, nonspecific symptoms
2. Microorganism is multiplying rapidly and causing fever and specific disease symptoms
3. decline of symptoms and return to a state of health
4. period of time from initial contact with pathogen to appearance of very first symptoms
- prodromal stage
- period of invasion
- convalescent period
- incubation period
Please match the description to the pattern of infection.
1. more severe infection, rapid onset
2. an infection that has spread to multiple body sites and tissue fluids; no longer restricted to one body site
3. Microbe enters the body and remains confined to a specific tissue
4. an infection that progresses and persists over a longer period of time; symptoms often less severe
5. a subsequent infection with a different microbe that may occur following an initial infection
- accute infection
- systemic infection
- localized infection
- chronic infection
- secondary infection
Reservoirs are always humans or other animals.
The primary habitat in the natural world from which a pathogen originates is its ________.
An individual who inconspicuously shelters a pathogen and spreads it to others without notice is a _______.
Please match the terms with the statements that most accurately describe them.
1. an individual who shelters a pathogen for a long period of time after recovery (example: Typhoid Mary)
2. a healthy individual who is infected but shows no symptoms
3. an individual recovering from a disease who continues to shed the pathogen during recuperation
4. an individual who picks up a pathogen while handling patients or contaminated supplies and spreads it to other individuals (frequently involved in nosocomial disease transmission)
- chronic carrier
- asymptomatic carrier
- convalescent carrier
- passive carrier
choose the statement that provides correct information about zoonoses.
70 percent of the new emerging infections seen today are zoonoses.
A ________ infectious disease, such as a urinary tract infection, is not transmitted from person to person, whereas an infectious disease which is transmitted from one person to another, such as influenza, is referred to as a ________ infectious disease.
select the patterns of direct (contact) transmission of infectious disease.
- kissing, touching
- mother to fetus (vertical)
select the patterns of indirect (vehicle) transmission of infectious disease.
- food / water
An infection that is acquired or develops during a person’s stay in the hospital is a _________ infection.
select the three most prevalent types of nosocomial infections.
-urinary tract infections
-surgical site infections
Universal precautions are specifically intended for the handling of patients and specimens known to be infected with pathogens such as HIV.
The study of the frequency and distribution
1. a disease pattern in which the number of new cases is increasing
beyond what is expected for the population
2. a disease pattern in which the number of new cases is increasing beyond what is expected, not just in a limited geographic area or population, but on more than one continent
3. a disease pattern in which occasional cases are reported at irregular intervals in random locations
4. a disease pattern with a relatively stable frequency over a long time period
order the four steps of Koch’s postulates as they would normally be applied.
choose the statement that best describes the use of Koch’s postulates.
Koch’s postulates are used to establish that a particular microorganism causes a specific disease.
What allows Salmonella to enter the intestinal cell?
protein secretion system
What cell component helps pull the Salmonella cells into the cell?
A second protein secretion system results in
a protective coating surrounding the infective bacterial cell
How does the protective coating help Salmonella evade destruction?
Lysosomes cannot fuse with the infectious cells.
What occurs within the protective coating?
The bacteria divide rapidly.
name the different types of occurences
The ______ is the sum total of genetic material in a cell.
In eukaryotic cells, what cellular structure is composed of a neatly packaged DNA molecule?
select all of the characteristics of DNA to test your understanding of its chemical structure.
correct Deoxyribose sugar
correct Phosphate group
correct Nitrogenous bases
DNA is the blueprint that indicates which kinds of proteins to make and how to make them.
Genetic ______ and the variations they produce result in population changes and thus, evolution.
When one bacterium donates DNA to another bacterium, a type of genetic recombination known as _________ has occurred.
horizontal gene transfer
Transformation is a mode of genetic recombination in which a plasmid is transferred from a donor cell to a recipient cell via a direct connection.
The acceptance by a bacterial cell of small DNA fragments from the surrounding environment is termed ________.
Please label the image to review how various antimicrobial agents alter protein structure and function.
1. use of a gaseous or liquid microbicide to destroy microorganisms
2. use of a filter to remove microorganisms from liquids or air
3. use of heat or radiation to destroy microorganisms
- chemical agents
- mechanical agents
- physical agents
Please order the following microbes or microbial forms in terms of their resistance to control methods, beginning with those that are mostresistant.
1. complete removal or destruction of all microbial forms
2. destruction or removal of vegetative pathogens (but not endospores) from inanimate surfaces
3. destruction of vegetative pathogens on skin and tissue
4. techniques that prevent the entry of microorganisms into sterile tissue
5. cleansing technique that removes microorganisms and debris from inanimate surfaces
A chemical labeled as ________ will inhibit bacterial growth but will not kill them.
1. use of chlorohexidine to prepare the skin prior to surgery
2. applying an antimicrobial chemical to your lab bench following completion of lab activities
3. use of an autoclave to prepare surgical instruments
4. wearing gloves and a face mask while performing surgery
5. cleaning eating utensils and plates in a restaurant
Please choose the statement that best defines microbial death.
The microorganisms are permanently unable to reproduce.
select the factors below that influence the effectiveness of an antimicrobial agent.
- number of microorganisms
- presence of organic matter
- concentration of dosage of the agent
select the four primary targets of antimicrobial control agents.
- cell wall
- cell membrane
- protein and nucleic acid synthesis
- protein structure and function
choose the statement that identifies the major disadvantage of both cold and desiccation in terms of microbial control.
These methods are bacteriostatic rather than bactericidal.
select the appropriate applications of cold and desiccation as microbial control strategies.
- preservation of microbial cultures
- preservation of food
Energy emitted as a result of atomic activity and dispersed at high velocity through matter and space is known as _______
choose the answer that correctly fills in the blanks of this sentence in order. _______radiation has good penetrating power and can be used for cold sterilization, whereas _______ radiation doesn’t penetrate well and is more often used for disinfection purposes.
A(n) _______ would be used to destroy bacteria on a countertop whereas a(n) _______ would be used on skin prior to making an incision.
select the factors that influence the effectiveness of antimicrobial chemicals.
- Numbers and kinds of microbes present
- Concentration of the chemical
- Presence of organic matter
- Nature of the material being treated
Please select the statement that describes the antimicrobial activity of alcohols.
disrupt membrane lipids and denature proteins
What type of bonds link individual amino acids together?
What type of bonds link individual amino acids together?
The helix that forms in a protein chain as a result of hydrogen bonds and other weak forces is an example of
secondary structure of protein.
In the stable form of protein, what is generally oriented to the interior of the protein molecule?
When an egg is fried, what happens to the protein in the egg?
The protein is denatured.
When forming a semi-solid gel such as gelatin, what type of molecule does the process of protein coagulation entrap?
True or false: All cases of Hepatitis C present with symptoms of nausea, vomiting, abdominal pain, and jaundice.
The patients who contracted HCV in this case were infected due to which of the following?
improper procedures for drawing up sedation drugs
HCV is mainly transmitted through what means?
True or false: All of the patients with acute HCV in this case were infected with strains of HCV that were genetically identical.
What is genetics?
the science that studies the inheritance of biological characteristics by life forms
What is a genome? What is the genome of bacteria, animals and plants?
the total genetic material carried within a cell
What are the levels of genetic study?
How is a genotype different from a phenotype?
The genotype is the set of genes in our DNA which is responsible for a particular trait. The phenotype is the physical expression, or characteristics, of that trait.
Describe the structure of DNA.
What are the 3 parts of a nucleotide?
- Nitrogenous Base.
- Pentose Sugar.
- Phosphate Group. A single phosphate group is PO4 3 -.
Which nitrogenous bases always hydrogen bond in pairs holding the two strands of DNA together?
a with t
c with g
What enzyme makes a DNA copy of DNA?
dna polymerase III
What enzyme makes an RNA copy of DNA?
What is transcription?
the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). DNA safely and stably stores genetic material in the nuclei of cells as a reference, or template.
What is translation?
a step in protein biosynthesis wherein the genetic code carried by mRNA is decoded to produce the specific sequence of amino acids in a polypeptide chain. The process follows transcription in which the DNA sequence is copied (or transcribed) into an mRNA
What does the ribosome do?
Ribosomes are where RNA is translated into protein. This process is called protein synthesis.
What is a codon?
a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule
What is a mutation?
A Mutation occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene.
Describe three means of genetic recombination in bacteria.
Bacterial recombination is a type of genetic recombination in bacteria characterized by DNA transfer from one organism called donor to another organism as recipient. This process occurs in three main ways: Transformation, Transduction, and. Conjugation.
Describe a biofilm.
Biofilm is an association of micro-organisms in which microbial cells adhere to each other on a living or non-living surfaces within a self-produced matrix of extracellular polymeric substance. Bacterial biofilm is infectious in nature and can results in nosocomial infections.
What microbes can be in a biofilm?
Many different bacteria form biofilms, including gram-positive (e.g. Bacillus spp,Listeria monocytogenes, Staphylococcus spp, and lactic acid bacteria, includingLactobacillus plantarum and Lactococcus lactis) and gram-negative species (e.g.Escherichia coli, or Pseudomonas aeruginosa).
What are planktonic cells?
Planktonic cells are classically defined “as free flowing bacteria in suspension” as. opposed to the sessile state (the so called biofilm): “a structured community of bacterial. cells enclosed in a self-produced polymeric matrix and adherent to an inert or living.
What are sessile cells?
How do bacteria communicate?
Quorum sensing: cell-to-cell communication in bacteria. Bacteria communicate with one another using chemical signal molecules. As in higher organisms, the information supplied by these molecules is critical for synchronizing the activities of large groups of cells.
Define and differentiate among the major terms for microbial control.
physical, mechanical, chemical
Identify the parameters of microbial death and describe several factors that influence the rate of death.
Identify the targets of antimicrobial control agents.
- Describe how each of the following physical methods suppresses microbial growth.
- ionizing and nonionizing radiation
Differentiate between ionizing and non-ionizing radiation in their modes of action.
Define the three levels of chemical decontamination procedures and place the following chemical agents in their appropriate category.
Describe how soap and alcohol work to kill germs.
dissolves membrane lipids and disrupt cell surface tension
State the goals of antimicrobial therapy.
What is selective toxicity?
Discuss the various origins of antimicrobial drugs
Summarize the five modes of action of antimicrobial drugs.
Explain how penicillin, vancomycin, zithromax and amoxillcillin work.
What is competitive inhibition?
List 2 genetic events that cause microbes to become resistant to drugs.
Explain 4 general mechanisms of drug resistance.
Why are there so few antifungal, antiparasitic, and antiviral drugs?
What are 3 adverse effects of antimicrobic drugs on the host?
What is the difference between infection and disease?
Where do you find normal microbiota?
Which sites of the body are microbe-free?
List several factors that predispose a person to disease.
Differentiate among the different portals of entry and give examples of pathogens that invade by these means.
Explain what is meant by the infectious dose, using examples.
Describe the process of adhesion and various mechanisms by which microbes use it to gain entry.
Describe the clinical stages of infection. (4 periods of disease)
Discuss the major portals of exit and how they influence the end stages of infection and disease.
List several examples of exoenzymes and their activities.
Compare and contrast the major characteristics of exotoxins and endotoxins
What are reservoirs of infection?
List several measures that health care providers must exercise to prevent nosocomial infections.
What are the 3 most common sites for nosocomial infections?
What are the 3 most common causes of nosocomial infections?
Summarize the steps in Koch’s postulates, and explain their importance to microbiologists
What is phage therapy?
How is phage therapy currently used in the US?
What are probiotics?
What are prebiotics?
What percent of infections involve biofilms?
What mechanisms make microbes in a biofilm hundreds of times more drug resistant than the same free, unattached microbes?
How is the clinical setting a source of drug-resistant strains of bacteria?
Is it just bacteria that becoming more resistant to drugs?
What other microbes are becoming more resistant to drugs?
What are the ESKAPE pathogens?
- Enterococcus faecium.
- Staphylococcus aureus.
- Klebsiella pneumoniae.
- Acinetobacter baumannii.
- Pseudomonas aeruginosa.
Phases of clinical trials
- Phase I trials: Researchers test an experimental drug or treatment in a small group of people (20–80) for the first time. The purpose is to evaluate its safety and identify side effects.
- Phase II trials: The experimental drug or treatment is administered to a larger group of people (100–300) to determine its effectiveness and to further evaluate its safety.
- Phase III trials: The experimental drug or treatment is administered to large groups of people (1,000–3,000) to confirm its effectiveness, monitor side effects, compare it with standard or equivalent treatments, and collect information that will allow the experimental drug or treatment to be used safely.
- Phase IV trials: After a drug is approved by the FDA and made available to the public, researchers track its safety, seeking more information about a drug or treatment’s risks, benefits, and optimal use.
is the process by which two or more alternative treatments are assigned to volunteers by chance rather than by choice. This is done to avoid any bias with investigators assigning volunteers to one group or another. The results of each treatment are compared at specific points during a trial, which may last for years. When one treatment is found superior, the trial is stopped so that the fewest volunteers receive the less beneficial treatment.
single-or double-blind studies
also called single- or double-masked studies, the participants do not know which medicine is being used, so they can describe what happens without bias. "Blind" (or "masked") studies are designed to prevent members of the research team or study participants from influencing the results. This allows scientifically accurate conclusions. In single-blind ("single-masked") studies, only the patient is not told what is being administered. In a double-blind study, only the pharmacist knows; members of the research team are not told which patients are getting which medication, so that their observations will not be biased. If medically necessary, however, it is always possible to find out what the patient is taking.
Microbes outnumber our cells by _______ times and occupy about ____%-____% of out body’s mass.
humans and their microbes as a single, functioning, interactive unit that shares nutrients, metabolism, genetic information and stays in constant communication.
the collective total of genetic material from all microbiota
Many species of microbes growing in and on the human body are cannot be cultured.
The Human Microbiome Project does not rely on culturing microbes.
The Human Microbiome Project takes samples from people, extracts DNA and sequences it to identify the microbes present.