Chapter 16, Infection Prevention & Control

Question 1

Infection

Answer 1

⬤ Infection: entry into the body of an infectious
agent (a microorganism) that then multiplies
and causes tissue damage
⬤ Pathogens: microorganisms capable of
causing disease***
⬤ Some microorganisms produce toxins and
others release endotoxins
⬤ Infection may result in illness and disease

Question 2

Infectious Agents

Answer 2

Bacteria
⬤ Prions
⬤ Viruses
⬤ Protozoa
⬤ Rickettsias
⬤ Fungi
⬤ Helminths
⬤ Others—mycoplasmas, Chlamydia

Question 3

Bacteria

Answer 3

⬤ Single-celled microorganisms lacking a
nucleus
⬤ Reproduce every few minutes up to several
weeks
⬤ Classified according to need for oxygen,
shape, and gram staining

Question 4

⬤ Need for oxygen

Answer 4

Aerobic: need oxygen to grow and thrive Anaerobic: can grow only without oxygen.

Question 5

Gram staining

Answer 5

Gram-positive bacteria retain the stain Gram-negative bacteria take up counterstain

Question 6

Shape

Answer 6

Cocci: round
Bacilli: rod-shaped
Spirochetes: spiral- or corkscrew-shaped

Question 7

Bacteria

Answer 7

⬤ Identified by chemical testing and growing
cultures
⬤ Sensitivity testing determines which antibiotic
can kill the organism
⬤ Some are drug-resistant

Question 8

Bacteria

Answer 8

Multidrug-resistant organisms
Methicillin-resistant Staphylococcus aureus
(MRSA)
Vancomycin-resistant Enterococcus (VRE)
Clostridium difficile (C. diff)
Penicillin-resistant Streptococcus pneumoniae

Question 9

Prions

Answer 9

Protein particles that lack nucleic acids and
are not inactivated by usual procedures for
destroying viruses
⬤ Do not trigger an immune response
⬤ Cause degenerative neurologic disease, such
as variant Creutzfeldt-Jakob disease (mad
cow disease)

Question 10

Protozoa

Answer 10

One-celled microscopic organisms belonging
to the animal kingdom

Question 11

Examples of pathogenic protozoa

Answer 11

Plasmodium species: causes malaria Plasmodium species: causes malaria
Entamoeba histolytica: causes amebic dysentery

Question 12

Viruses

Answer 12

Extremely small; seen only with an electron
microscope
⬤ Composed of particles of nucleic acids, either
DNA or RNA, with a protein coat
⬤ Grow and replicate only within a living cell;
survival and replication depend on host tissue

Question 13

Rickettsia

Answer 13

Small round or rod-shaped organisms
⬤ Transmitted by the bites of fleas, lice, mites,
and ticks
⬤ Can multiply only in host cells
⬤ Causes Rocky Mountain spotted fever and
typhus

Question 14

Fungi

Answer 14

Tiny primitive organisms of the plant kingdom
that contain no chlorophyll
⬤ Include yeast and mold
⬤ Feed off living animals and decaying organic
matter
⬤ Reproduce by use of spores
⬤ Cause candidiasis and tinea pedis (athlete’s
foot

Question 15

Helminths

Answer 15

Parasitic worms or flukes
⬤ Belong to the animal kingdom
⬤ Pinworms, which mostly affect children, most
common helminths worldwide
⬤ Roundworms and tapeworms are other
helminths

Question 16

Other Infectious Agents

Answer 16

Mycoplasmas
Very small organisms without a cell wall
Example: Mycoplasma pneumoniae

Question 17

⬤ Chlamydia

Answer 17

Affects the genitourinary and reproductive tracts

Question 18

Process (Chain) of Infection

Answer 18

An infectious disease is spread from one
person to another; a continuous chain
⬤ Chain links Causative agent (link 1)
Reservoir Portal of exit
Mode of transfer
Portal of entry
Susceptible host

Question 19

Causative Agent (Link 1)

Answer 19

Any microorganism or biologic agent capable of
causing disease
⬤ Bacteria, viruses, protozoa, rickettsias, fungi,
helminths

Question 20

Virulence of the agent is affected by its ability to:

Answer 20

Adhere to mucosal surfaces or skin Penetrate mucous membranes Multiply once in the body Secrete harmful enzymes or toxins Resist phagocytosis

Question 20

Reservoir (Link Two)

Answer 20

Infected wounds, human or animal waste, animals
and insects, contaminated food and water, and the
person with an infection

Question 20

Precautions to prevent the spread of infection

Answer 20

Good hand hygiene
Sterile technique

Question 20

Route by which pathogen leaves its host

Answer 20

• Feces may transport the typhoid bacillus from an infected
  perso

Question 21

Respiratory tract

Answer 21

Microorganisms are released with coughing or sneezing
* Measles, mumps, pulmonary tuberculosis can be
transmitted by exit from the respiratory tract Skin and mucous membranes
* Open wound

Question 22

Modes of Transfer (Link Four

Answer 22

Direct personal contact with body excreta or
drainage from an ulcer, infected wound, boil, or
chancreDroplet infection, or contamination by the aerosol
route through sneezing and coughing
⬤ Spread of infection from one body part to another
⬤ Indirect contact with contaminated inanimate
⬤ Vectors, such as mosquitoes, that harbor infectious
agents and transmit through bites and stings Droplet infection, or contamination by the aerosol
route through sneezing and coughing
⬤ Spread of infection from one body part to another

Question 23

Portal of Entry (Link Five)

Answer 23

Enter the body through eyes, mouth, nose,
trachea, skin, mucous membranes Use only sterile and clean items in patient care
⬤ To prevent entry of microorganisms: Use only sterile and clean items in patient care Use barrier precautions (gloves, masks, condoms)
Safely handle food and water Use good personal hygiene Avoid high-risk behaviors
Use protection from insect bites and stings