microbiology test 2

If there is 25 total cases in a defined population during a given time, and 100 total people in the defined population during the same time, what is the prevalence rate?

0.25

Which of the following is the best definition for the term attenuated?

A microorganism that is infectious but is weakened to the point of being unable to cause disease in an immunocompetent host

Which of the following is/are an example of a healthcare-acquired infection?

A nursing home patient develops a urinary tract infection from a contaminated catheter in a nursing home facility. A hospitalized patient develops Staphylococcal sepsis after a nurse transmits the pathogen to the patient while changing wound dressing. A patient develops pneumonia after using a contaminated ventilator at an outpatient care facility.

Which of the following is/are primary reason(s) why healthcare settings are hot zones for antibiotic-resistant pathogens?

Abundance of susceptible, immunocompromised patients Extensive use of antibiotics among patients

As a healthcare worker, which of the following can help in managing outbreaks?

Advocate for refresher training in standard procedure and precautions needed to limit the spread of pathogenic microorganisms. Learn how to properly put on and remove personal protective equipment. Report potential dangers to supervisor.

Which of the following is an example of a direct contact transmission?

An individual contracts rabies after being bitten by a rabid raccoon.

Which of the following is/are examples of virulence factors?

Capsule Iron-binding proteins Flagella

Which of the following factors contribute to the evolution of virulence factors?

Competency of host immune system Presence of antibiotic in the environment Host normal microbiota balance

You observe a high proportion of malarial infections in a small village located in Angola. Malaria is caused by the protozoan Plasmodium and is spread through the female Anopheles mosquito, a biological vector for this disease. Which of the following is a basic strategy that would help to break the epidemiological triangle of malaria? To be marked correct, you'll need to select all applicable statements, as there may be more than one correct answer.

Controlling the biological vector through chemical larvicides Instructing residents on personal protective measures, such as bed netting and use of DEET repellent

The hygiene hypothesis proposes which of the following?

Decreasing diversity of our normal flora from increased antibiotic usage and changes in diet and lifestyle may lead to increased allergies and autoimmune disorders.

Which of the following factors allows for the best chance of disease eradication?

Disease is preventable through vaccination

Which of the following statements correctly describes Dr. Ignaz Semmelweis's contribution to hospital epidemiology?

Dr. Semmelweis demonstrated that handwashing prior to examining patients cut down on the incidence of nosocomial infections.

Which of the following statements regarding tropism is/are true?

Even if a pathogen successfully invades its preferred host tissue, it may not necessarily cause disease. Most emerging pathogens have expanded host or tissue range.

Which of the following statements is/are ways in which fever is protective?

Fever increases phagocytic efficiency. Fever enhances antiviral properties of interferon. Fever limits the growth of heat-sensitive pathogens.

Which of the following statements is/are true regarding T cytotoxic cell antigen elimination?

Following apoptosis by cytotoxic T cells, macrophages and natural killer cells clear the dead cells. Once the threat has been detected by the T cell receptor, the cytotoxic T cell releases perforins that form pores in the target cell and granzymes, which enter through pores to trigger apoptosis. Interferons released by infected or cancer cells attract and activate cytotoxic T cells, while cytokines released by the cytotoxic T cells attract natural killer cells and macrophages.

Which of the following is an example of dysbiosis?

Following extended use of amoxicillin, your patient develops oral thrush as a result of the overgrowth of Candida albicans.

Cholera, salmonella, and C. difficle all use which of the following portals of entry?

GI mucosa

Which of the following is a common healthcare-acquired infection?

Gastrointestinal infection caused by Clostridium difficile

Which of the following statements describes the purpose of gene shuffling?

Gene shuffling generates an enormous repertoire of antigen receptors during lymphocyte development.

Which of the following describes the general goal(s) of the second-line molecular defenses?

Generate fever Recruit leukocytes to sites of infection Induce inflammation

Which of the following statements accurately describes the way(s) in which granulocytes and agranulocytes differ?

Granulocytes have granules in their cytoplasm that are visible with light microscopy, whereas agranulocytes do not have granules in their cytoplasm. Granulocytes consist of neutrophils, mast cells, eosinophils, and basophils, whereas agranulocytes consist of lymphocytes, dendritic cells, and monocytes.

Which of the following is/are standard precaution(s)?

Hand hygiene should be performed before and after each patient contact Surfaces must be disinfected. New gloves should be worn when encountering blood, mucous membranes, non-intact skin, or other bodily fluids, and gloves should be changed between procedures.

Which of the following statement(s) concerning quarantines is/are true?

If the typical incubation period passes without development of symptoms, quarantined individuals are typically released. If disease develops in the quarantined individual, a quarantine may be maintained until the convalescent period. Quarantines may be performed on either animal and/or human hosts.

Your patient has an anaphylactic response to bee venom. Which of the following classes of antibodies would you expect to be elevated in the patient's serum, based on this hypersensitivity?

IgE

Which of the following statements is true concerning the alternative complement cascade?

In the alternative complement cascade, complement proteins directly interact with the invading agent.

Which of the following is a key factor that contributes to reemerging disease?

Increased antibiotic resistance in a well-known pathogen leads to increased incidence rates.

Which of the following statements accurately describes innate immunity?

Innate immunity has an immediate response to antigens. Innate immunity has the capacity to distinguish foreign versus self.

Which of the following is a general goal of epidemiology? To be marked correct, you'll need to select all applicable statements, as there may be more than one correct answer.

Intervene to protect and improve health in populations. Describe the nature, cause, and extent of new and existing diseases in populations.

Your laboratory is working with Clostridium tetani, the etiological agent for tetanus. Which of the following minimum personal protective equipment (PPE) are relevant for this type of pathogen?

Lab coats, gloves, and safety goggles or a face shield (if there is splash risk) should be worn.

Which of the following scenarios provides an example of isotype switching?

Late in an infection with Influenza virus, a given plasma cell stops production of IgM and begins producing IgG.

Which of the following criteria is/are used to assign pathogens to a specific biosafety level?

Level of infectivity Mode of transmission Availability of preventions and treatments for the disease

Which of the following sequences describes the flow of lymph through the lymphatic system?

Lymphatic capillaries, lymphatic vessels, lymph node, lymphatic trunk

Which of the following is part of the second line of defense?

Molecular factors such as chemokines Leukocytes

Which of the following is/are a role(s) of the public health system?

Monitoring disease within a population Developing policy and plans that support good community health Mobilizing health resources to meet needs

Which of the following statements regarding the National Notifiable Diseases Surveillance System is/are true?

Most states within the United States have laws requiring healthcare providers and laboratories to report certain diseases to local and state authorities. The United States Center for Disease Control and Prevention publishes the Morbidity and Mortality Weekly Report to update health officials and care providers on national health issues.

Which of the following is an example of a reemerging disease?

Mumps, once nearly eliminated, has increased in prevalence due to under-vaccination in industrialized countries

Your patient has an active case of tuberculosis. Which of the following transmission precautions should be used when working with this patient?

N95 or comparable respirator Place patient in an airborne infection isolation room

Which of the following statements concerning natural killer cells is true?

Natural killer cells provide protection against viruses, bacteria, parasites, and tumors.

Group B streptococci (GBS) are known to cause life-threatening disease in some newborns, but are commensals in the adult female vagina. Which of the following helps to explain why GBS acts as a pathogen in newborns and as a commensal in healthy adults?

Newborns have reduced immunity compared to healthy adults. Newborns lack firmly established normal flora that compete with the opportunistic pathogen

Which of the following statements concerning T cell self-tolerance screening is true?

Once T cells pass the self-tolerance screening, they migrate to lymphoid tissues.

Which of the following statements regarding B lymphocytes is/are true?

Once activated, B lymphocytes have the ability to produce antibodies. B lymphocytes are both produced and mature in the bone marrow.

Candida albicans is part of our normal oral flora. Under certain conditions, it can overgrow, leading to oral thrush. Typically, infections are seen in individuals who are immunocompromised, such as newborns or individuals who may have recently taken antibacterial medications. This type of pathogen is classified as which of the following?

Opportunistic, endogenous pathogen

You receive an accidental needle stick from a needle contaminated with Hepatitis B virus. In this example, Hepatitis B enters the host through which portal of entry?

Parenteral entry

Choose the true statement(s) about ethical issues in epidemiology.

Public health priorities should be based on evidence and not on political agendas. To allow for disease eradication, individual rights to forgo vaccination should be surrendered for the common good. Genetic information of a patient should be kept private and should not be used as a basis of discrimination.

Second-line molecular defenses fulfill which of the following immunological roles?

Recruit leukocytes to site of infection Stimulate fever Stimulate inflammation

Which of the following statements concerning second-line molecular defenses is true?

Second-line molecular defenses are produced by leukocytes

Siderophores such as enterobactin promote virulence through which mechanism?

Sequesters iron from the host

Which of the following is an organic molecule made by bacteria that sequesters iron from host iron-binding proteins?

Siderophore

Which of the following modes of action do antimicrobial peptides use to combat pathogens?

Stimulate leukocyte to modulate inflammation Target pathogen intracellular components such as protein and/or DNA Disrupt cell wall and/or plasma membrane of pathogen

Which of the following statements is true regarding superantigens?

Superantigens trigger the release of high levels of inflammatory cytokines, such as tumor necrosis factor alpha and interferon gamma by CD4 T cells.

If an antigen-presenting cell releases primarily interleukin 2 and interleukin 4, you would expect to see more development of ____ cells, which would trigger a(n) _____ response.

TH2; humoral

Which of the following symptoms and signs of infection are associated with septic shock?

Tachycardia (increased heart rate) Fever A feeling of disorientation

Which of the following statements is true concerning cellular immunity?

The cellular branch of adaptive immunity is mainly organized by T helper cells and carried out by T cytotoxic cells.

Which of the following provides the best definition of the term reservoir?

The habitat where a pathogen is typically found.

Which of the following is an example of a mechanical barrier?

The mucociliary escalator sweeps mucus away from the lungs and toward the mouth.

Which of the following descriptions provides the best definition for mortality rate?

The number of deaths during a specific time period

Which of the following statements concerning the secondary response is true?

The secondary response results in production of antibodies with a higher affinity for the antigen.

Which of the following properties of skin makes it an effective first line of defense?

Tightly-packed epithelial cells help to reduce pathogen entry. Keratin and lipids allow for skin to be water-resistant. Skin cells make antimicrobial peptides which destroy a variety of microorganisms.

Which of the following statements accurately differentiates the adaptive immune system and the innate immune system?

Unlike the innate immune system, the adaptive immune system includes both a cellular and humoral response. Unlike the innate immune system, the adaptive immune system is characterized by memory and specificity.

During which stage of infectious disease is the disease at its peak?

acute phase

An N95 mask is a transmission precaution for which of the following?

airborne

Where do the majority ofhuman infections originate from?

biofilms

Patients infected with Herpes simplex virus-1, the causative agent of fever blisters, go through periods of viral inactivity (where no active oral cankers appear) and outbreaks (where fever blisters are present). This type of individual is best defined as a(n) _______________.

chronic carrier

Which complement pathway is activated when antibodies bind to a pathogen?

classical pathway

A key test used to differentiate Staphylococcus aureus from Staphylococcus epidermidis relies on the microorganism's ability to clot blood plasma fibrin. Based on this information, this distinguishing assay tests for the invasin

coagulase

Limiting patient transport is important in which of the following precautions

contact, droplet, and airborne precautions

What is Dr. Ignaz Semmelweis best known for?

developing aseptic techniques

Which of the following bacterial toxins usually act as pyrogens?

endotoxins

Which of the following is matched correctly?

environmental-direct

Which leukocytes help with fighting off allergies?

eosinophils

Which of the following would be considered a sign?

fever

A histiocyte is an agranulocyte that is exclusively present in connective tissue. Which of the following terms best describes a histiocyte?

fixed macrophage

Which of the following is not an Adhesin?

flagella ARE heparan sialic acid binding factors fibronectin binding factors fimbaire

What group of pathogens does a Hookworm fall under?

helminths

chemical mediator of inflammation?

histamine kinins leukotrienes prostaglandin

Cytokines signal the ______________ to raise the body temperature.

hypothalamus

CD8 T cell activation occurs through _______, involving presentation of antigen with _______.

intracellular antigen presentation; MHC I molecule

The ability of a pathogen to quietly exist inside a host cell is called

latency

What is another term for white blood cells?

leukocytes

Endotoxins are made of which of the four macromolecules?

lipids

Which leukocytes have large horseshoe-shaped nucleus?

monocytes

Escherichia coli living in the human large intestine is known to produce vitamin K and B-complex vitamins in exchange for a nutrient-rich habitat. This host-microbe interaction is an example of __________.

mutualism

Patients with conjunctivitis often can be seen rubbing their itchy, irritated reddened eye(s). Based on this symptom of infection, which of the following modes of transmission is most likely?

ocular

While hiking, you sprain your ankle. Which of the following signs and symptoms of inflammation should you observe?

pain swelling

The 1918 influenza virus killed more individuals worldwide than World War One. It is estimated that between twenty and forty percent of the world's population across continents had become infected with the virus, leading to 50 million deaths. The 1918 influenza would best be described as which of the following?

pandemic

What does herd immunity mean?

pathogens won't find enough susceptible people in the community to persist

Which of the following is/are (a) mechanism(s) through which antibodies increase phagocytosis?

precipitation Opsonization Agglutination

Which of the following is the most important yet overlooked factor for preventing HAIs?

proper hand washing

One out of every 1,000 children who contract measles will develop encephalitis. This statistic is a measure of _______.

proportion

Which of the following is not used to assign a biosafety level?

rRNA sequences ARE level of infectivity extent of disease caused and mortality rates mode of transmission availability of preventions and treatments of disease

______________ are used to compare the occurrence of an event in one group compared to another group.

ratios

Which of the following ways for pathogens to escape phagocytosis does not currently exist in nature

releasing toxins that kill phagocytes avoiding phagocytosis with a capsule blocking fusion of lysosome with phagosome escaping phagosome and living in phagocytic cell adopting to the harsh environment of the phagolysosome neutralizing hydrolytic enzymes inside the phagolysosome ***all of the above have been observed

Which fever classification is defined as having an elevated body temperature that fluctuates but does not reach normal in the course of the fluctuations?

remittent

Which of the following statements describes a physiological effect of kinin production?

stimulate pain receptors Promote vascular changes Assist in blot clotting cascades

Koch's postulates apply to

susceptible diseases reemerging diseases infectious diseases transmittable diseases

What is an example of a mechanical barrier?

tears rinse microbes away

Epidemiological measures are useful tools because:

they help determine which diseases may need greater public health campaign or prevention efforts.

Which of the following is part of the primary lymphoid tissues?

thymus and bone marrow

Which of the following statements best describes the goal of the first line of immune defense?

to prevent pathogen entry

Gonorrhea, chlamydia, and certain papillomaviruses all use which of the following portals of entry?

urogenital/reproductive system