Microbiology Ch. 11

Select the three basic ways in which microbes cause tissue damage.

- Microbes release toxins that cause tissue damage. - Microbes release enzymes that break down host tissue. - Microbes activate a host response that is itself destructive to host tissue.

Select all of the statements that correctly describe the infectious dose.

- The infectious dose is the minimum number of organisms that must be present for an infection to proceed. - Microbes with low infectious doses are usually highly virulent. - Certain infections, like tuberculosis and giardiasis, may proceed even if only a small number of microbial cells are present.

Select those circumstances in which Koch's postulates cannot be readily applied or would be inappropriate to establish the cause of a disease.

- The suspected pathogen cannot be cultured in the laboratory. - There is not a suitable experimental host for the suspected pathogen. - The disease is polymicrobial, caused by more than one pathogen.

Fecal transplants have been approved for use in patients with hard-to-treat _____________________ infection.

Clostridium difficile

Select characteristics exhibited by endotoxins, but not exhibited by exotoxins.

Composed of lipopolysaccharide Heat-stable Fever-inducing

In order to prevent the spread of disease to other patients, the RN observes all of the following precautions, except:

Disinfection of needles following injections

Infectious disease

Disruption of a tissue or organ caused by microbes or their products.

The RN advises the employee that she is at risk for which of the following diseases?

HIV Hep B Hep C

Passive Carrier

Health care workers who accidentally transfer pathogens to patients

The patient developed the infection since hospitalization. Which of the following terms best describes this type of infection?

Healthcare-associated infection

The RN has administered a dose of antibiotics to the mother as ordered. Which of the following statements by the patient demonstrates understanding of the rationale for antibiotics?

I need antibiotics because my child is at risk of infection due to premature rupture of membranes.

Asymptomatic carrier

Infected, but shows no symptoms of disease

Acute Infection

Infection comes on rapidly, with severe but short-lived effects

Systemic Infection

Infection spreads to several sites and tissue fluids, and may travel via nerves and CSF

Chronic Infection

Infection that persists over a long period of time (e.g., HIV)

Convalescent carrier

Recuperating patients without symptoms; may shed viable microbes

If the patient is found to test positive for HIV, hepatitis B, or hepatitis C, which of the following actions is legally required by the hospital facility?

Reporting the patient's positive test result to public health authorities

Mixed infection

Several microbes establish themselves simultaneously at the infection site

Chronic carrier

Shelters the infectious agent in a latent form for a long period after recovery

Incubating carrier

Spreads the infectious agent before the appearance of the first symptoms

Focal Infection

The infectious agent spreads to other tissues from a local site

Primary Infection

The initial infection

Common - source epidemic

The persistent cholera epidemic studied by John Snow in London during the mid-1050s, during which he traced the source to a sewage-contaminated community pump.

As the symptoms of the infection decline, the patient enters a period of recovery called the ________________ period.

convalescent

Which of the following statements is true regarding reportable diseases?

There are over 75 reportable diseases caused by a large variety of microorganisms.

A teacher walking through her first-grade classroom pauses to pick up a used tissue that had ended up on the floor instead of in the waste basket. Unfortunately, after discarding the tissue, she doesn't immediately wash her hands, and acquires a strain of rhinovirus. Several days later she begins to experience symptoms of a cold. Based upon this scenario, please select the mode of disease transmission demonstrated here.

fomite

Select the patterns of indirect transmission of infectious disease.

food, water fomites air

There are ____________ distinct phases of infection and disease.

four

An infection that is acquired or develops during a person's stay in a hospital or other health facility is called a(n) _____________

healthcare-associated

By law, certain _________ diseases must be recorded with the public health authorities in order to maintain proper surveillance at the local, state, national, and international levels.

reportable

Select characteristics exhibited by exotoxins, but not exhibited by endotoxins.

require very small doses to cause toxic effects secreted from a living cell have very specific targets

Select the three most prevalent types of healthcare-associated infections.

surgical site infections urinary tract infections respiratory infections

One must note that ____________ of a microbe during these four stages varies for every pathogen.

transmissibility

Typical treatments for this infection include the use of potent antibiotics such as ______________; however, the use of this drug only results in a ____ cure rate.

vancomycin; 31%

If an infant is exposed to Hepatitis B from breast milk, which term best describes the pattern of transmission?

vertical transmission

Select the two major goals of the Human Microbiome Project.

- To enumerate all of the members of the human microbiota, both those that can be cultured and those that are nonculturable - To determine the role the human microbiota plays in health and disease

Exotoxin

- hemolysins produced by streptococcus pyogenes - action is specific to one cell type - clostridium tetrani tetanospasmin

Endotoxin

- lipopolysaccharride - systemic effect on many tissues and organs - fever-inducing

Urogenital tract

- microbes enter through mucosa of penis or vagina - HIV, trichomoniasis, candida albicans

Gastrointestinal tract

- microbes enter via food, water or fomites - salmonella, shigella, hepatitus A

Respiratory tract

- microbes enter via inhalation - flu, mycobacterium, TB, cryptococcus

Skin

- microbes enter via insect bites, conjunctiva, or oral mucous membranes - staph, herpes simplex (type 1), and west nile virus

Exoenzyme

- mucinase produced in amoebic dysentery - hyaluronidase produced by strep and staph - coagulase produced by staph - kinases (streptokinase, staphylokinase)

Order the four steps of Koch's postulates as they would normally be applied.

1 - find evidence of a particular microbe in every case of a particular disease 2 - isolate the suspected microbe from an infected host and cultivate it in pure culture in the lab 3 - inoculate a susceptible healthy subject with lab isolate of the potential pathogen and observe the resultant disease 4 - reisolate the disease agent from the test subject which now shows signs of disease

Order the four stages in the course of an infection.

1 - incubation period 2 - prodromal stage 3 - period of invasion 4 - convalescent period

Percentage of healthcare-associated infections involving surgical sites

19%

Percentage of healthcare-associated infections involving the urinary tract

40%

Average rate of healthcare-associated infections in all admitted patients

5%

In 2013, a study was published that indicated a _____ cure rate in patients treated with these transplants.

94%

Percentage of all healthcare-associated infections caused by gram-negative intestinal biota

>50%

All are important topics to teach an employee, except which of the following?

A patient's infectious status must be known when reporting to employee health so immediate treatment may be initiated.

Secondary Infection

An example is influenza complicated by pneumonia

Point-source epidemic

An outbreak of Staphylococcal food poisoning among individuals who attended a family reunion and ate the potato salad.

Propagated epidemic

An outbreak of chickenpox among unvaccinated children in a large Amish community

The mother displays no evidence of active Hepatitis B disease as her carrier status was discovered with routine prenatal screening. What term best describes her carrier state?

Asymptomatic carrier

All of the following factors increase the patient's risk for Clostridium difficile infection, except:

Genetic defect

Localized Infection

Microbes enter the body and remain confined to a specific tissue

_________ pathogens, like Candida or Pseudomonas, are not usually pathogenic to healthy persons with normal immune system functions because these microbes do not have well-developed virulence factors.

Opportunistic

Colonization

Presence of organisms living in or on the body, but not causing any pathology.

Which of the following is the first exposure of the infant to environmental microbes?

Passage through vaginal canal

Infection

Pathogenic microorganisms penetrate the host defenses, enter the tissues, and multiply.

Please choose the answer that best completes the blanks of this sentence in the correct order. _________ is the ability of a microbe to cause disease, whereas _________ refers to the relative severity of a disease caused by a particular microorganism.

Pathogenicity; virulence

The patient is experiencing severe diarrhea every 6 hours. Which phase of infection is she most likely experiencing?

Period of invasion

Epidemiology is the study of disease in the __________.

community

Choose the best definition of virulence factors.

characteristics of a microorganism that enable it to establish infection and cause disease

During 2007, there were 3.6 new cases of pertussis per 100,000 susceptible individuals in the United States, part of a steady increase that has been occurring since the 1980s.(http://www.cdc.gov/pertussis/clinical/index.html). Please select the term that is illustrated by this statistic.

incidence

The _____________ period is the first phase, and is the time from initial contact with the infectious agent to the appearance of the first symptoms.

incubation

During the period of _____________, the infectious agent multiplies at high levels and becomes well established in its target tissue.

invasion

Select the patterns of direct transmission of infectious disease.

kissing, touching mother to fetus (vertical) droplet

Fecal transplants involve administration of an enema containing donor feces in an effort to replace the normal ______________ of the gastrointestinal tract.

microbiota

Select all of the sites where it was previously known that normal microbiota existed in large populations in/on the human body.

mouth throat colon skin vagina

This organism is a gram- _____________ bacterium and causes pseudomembranous colitis, infection of the ________________.

positive; colon

During a recent survey, 0.014% of the population showed evidence of a particular respiratory infection. Please select the term that is illustrated by this statistic.

prevalence

The earliest notable symptoms of most infections appear during a short period known as the _____________ stage.

prodromal