week 4: Ch. 6- Infection

Question 1

Pathogens:

Answer 1

Disease-causing microbes

Question 2

Bacteria

Classified as:
Function:
Divide by:
Structure:
Appearance:

Answer 2

◦ Classified as prokaryotes
◦ No nuclear membrane—no nucleus
◦ Function metabolically & reproduce
◦ Divide by binary fission
◦ Complex cell wall structure
◦ Do not require living tissues to survive
◦ Vary in size and shape

Question 3

Bacilli

Answer 3

Rod-shaped organisms

Question 4

Spirochetes

Answer 4

Include spiral forms and Vibrio spp.

Question 5

Cocci

Answer 5

Spherical forms
◦ Diplococci
◦ Streptococci
◦ Staphylococci

Question 6

Two types of bacteria that differ in chemical composition:

Answer 6

◦ Gram-positive
◦ Gram-negative

Question 7

External capsule or slime layer

Answer 7

◦ Found in some bacteria
◦ Outside the cell wall
◦ Offers additional protection

Question 8

Flagellae

Answer 8

◦ One or more attached to cell wall
◦ Provide motility for some species

Question 9

Pili or fimbriae

Answer 9

◦ Tiny hairlike structures—found in some bacteria
◦ Assist in attachment to tissue
◦ Transfer of DNA to another bacterium

Question 10

Cell membrane

Answer 10

◦ Inside the bacterial cell wall
◦ Selectively permeable

Question 11

Cytoplasm contains:

Answer 11

◦ Chromosome- One long strand of DNA
◦ Ribosomes and RNA
◦ Plasmids- DNA fragments; nonchromosomal; exchange DNA during conjugation

Question 12

Exotoxins are usually produced by:

Answer 12

gram-positive bacteria

Question 13

Endotoxins

Present in:
Released:
Can cause:

Answer 13

◦ Present in the cell wall of gram-negative bacteria
◦ Released on death of bacterium
◦ Vasoactive compounds that can cause septic shock

Question 14

Spores

Formed by:
__________ form of bacterium
Can survive:
Highly resistant to:

Answer 14

◦ Formed by several species
◦ Dormant-latent form of bacterium
◦ Can survive long periods of time in spore state
◦ Highly resistant to heat and disinfectants

Question 15

Viruses are small:

Answer 15

obligate intercellular parasites

Question 16

Viruses structure

Answer 16

◦ Protein coat or capsid
-protein coat comes in various shapes and sizes

◦ Can change (mutate) quickly

◦ Nucleic acid - DNA or RNA
◦ Classification dependent on nucleic acid present
◦ Some RNA-containing viruses contain reverse transcriptase enzyme to convert RNA to DNA.

Question 17

Active Viral Infection steps

◦ Virus attaches to ___________
◦ Viral ___________ material enters cell.
◦ Viral _______________ takes control of cell.
◦ Uses host’s cell to synthesize ____________________________________________
◦ New viruses are assembled in cytoplasm of cell.
◦ Viruses released by ____________________________ from host cell membrane

Answer 17

◦ Virus attaches to host cell.
◦ Viral genetic material enters cell.
◦ Viral DNA or RNA takes control of cell.
◦ Uses host’s cell to synthesize viral proteins & nucleic acids
◦ New viruses are assembled in cytoplasm of cell.
◦ Viruses released by lysis of host cell or by budding from host cell membrane

Question 18

Latent Viral Infection steps

◦ Virus enters cell as with active infection.
◦ Viral _________ are produced and Inserted into [may stimulate an immune response and destruction of host cell]

◦ Virus may ____________________________ if immune system is depressed (e.g., herpesviruses)

Answer 18

◦ Virus enters cell as with active infection.
◦ Viral proteins are produced and Inserted into [may stimulate an immune response and destruction of host cell]

◦ Virus may reproduce actively if immune system is depressed (e.g., herpesviruses)

Question 19

Describe characteristics of Chlamydia, Rickettsiae,
Mycoplasmas

Answer 19

◦ Obligate intercellular parasites.
◦ Do not grow on artificial media
◦ Some similarities with both bacteria and viruses
◦ Lack some basic components
◦ Classified as bacteria
◦ Replicate by binary fission within host cell

Question 20

Chlamydia

~cause of? results in?

Answer 20

◦ Common cause of sexually transmitted disease
◦ Can result in infertility

Question 21

Rickettsiae

~Gram? Transmitted by?

Answer 21

◦ Gram-negative
◦ Transmitted by insect vectors (lice, ticks)

Question 22

Mycoplasmas

~Lack? Causes?

Answer 22

◦ Lack cell wall
◦ Cause of atypical type pneumonia

Question 23

___________ (fungus) can cause neurologic disease and can be transmitted to embryo or fetus if mother is infected

Answer 23

Histoplasma

Question 24

Fungi

◦ ________________ organisms (contain nucleus)
◦ Found throughout environment - On animals, plants, humans, food
◦ Fungal or mycotic infection
◦ From single-celled_________ or multicellular molds
◦ Only a few are _________________.
◦ Cause primary infection on skin or mucous membranes but may spread systemically particularly in immunosuppressed individual

Answer 24

◦ Eukaryotic organisms (contain nucleus)
◦ Found throughout environment - On animals, plants, humans, food
◦ Fungal or mycotic infection
◦ From single-celled yeast or multicellular molds
◦ Only a few are pathogenic.
◦ Cause primary infection on skin or mucous membranes but may spread systemically particularly in immunosuppressed individual

Question 25

_______________ (fungus) is AKA athlete’s foot

Answer 25

Tinea pedis

Question 26

Candida (fungus): usually harmless, but opportunistic ◦ Causative agent of :

Answer 26

thrush and vaginitis

Question 27

Protozoa

Answer 27

◦ Eukaryotic forms ◦ Unicellular, lack cell wall ◦ Many live independently, others are obligate parasites ◦ Pathogens are usually parasites. ◦ Examples of protozoal diseases: -Trichomoniasis -Malaria -Amebic dysentery

Question 28

Helminths (flatworms or roundworms)

Answer 28

◦ Are not microorganisms ◦ Parasites ◦ May be small or up to 1 m in length ◦ Life cycle with 3+ stages- Ovum, larva, adult ◦ Enter body through skin or by ingestion ◦ Infections more commonly found in young childs ◦ Infection can be life-threatening in an immunosuppressed client.

Question 29

___________: ova inhaled in dust in fecally contaminated areas; common in children worldwide

Answer 29

Pinworms

Question 30

__________: larvae enter skin from fecally contaminated soil in tropical areas

Answer 30

Hookworms

Question 31

________________: most common form transmitted by larvae in undercooked pork

Answer 31

Tapeworms

Question 32

___________—giant roundworm: ingested with food that has been grown in feces-contaminated soil or prepared with hands that have been in feces-contaminated soil

Answer 32

Ascaris

Question 33

Prions

Answer 33

◦ Protein-like agents that change the shape of proteins within host cells ◦ Transmitted by contaminated tissues ~Ingestion of meat/ Infected blood or donor organs ◦ Cause degenerative disease of nervous system ◦ Human prion diseases ~Creutzfeldt-Jacob disease and variant Creutzfeldt-Jacob disease ~Both rapidly progressive and fatal

Question 34

Many areas of the body have a resident population of mixed microorganisms termed ______________________ in the ◦ Skin ◦ Nasal cavity ◦ Mouth ◦ Gut ◦ Vagina ◦ Urethra

Answer 34

resident/normal flora.

Question 35

Infection—organism is able to:

Answer 35

reproduce in or on body’s tissues

Question 36

◦ Endemic VS ◦ Epidemic VS ◦ Pandemic

Answer 36

◦ Endemic: Continuous transmission within a population ◦ Epidemic: Higher than normal transmission or spread to new geographical area ◦ Pandemic: Transmission has occurred on most continents.

Question 37

Reservoir

Answer 37

◦ Source of infection ◦ Person with active infection OR ◦ Person who is asymptomatic ◦ Environmental source such as contaminated soil, Infected person or animal

Question 38

Carrier

Answer 38

◦ A person may never develop the disease but still is a carrier. ◦ A person with subclinical signs of the disease

Question 39

_______: the microbe causing the infection

Answer 39

Agent

Question 40

________ _____ ____: means whereby the agent leaves the reservoir

Answer 40

Portal of exit:

Question 41

_________ ___ ______________: method whereby the agent reaches a new susceptible host ◦ Air ◦ Water ◦ Direct contact ◦ Food

Answer 41

Mode of transmission

Question 42

________________: access to new host

Answer 42

Portal of entry

Question 43

Susceptible host: susceptibility will depend on:

Answer 43

◦ Health status ◦ Immunity ◦ Age ◦ Nutrition

Question 44

Transmission could be direct or indirect:

Answer 44

Direct contact ◦ No intermediary ◦ Touching infectious lesion, sexual activity ◦ Contact with infected blood or bodily secretions Indirect contact ◦ Involves intermediary object or organism ◦ Contaminated hand or food ◦ Fomite—inanimate object

Question 45

____________ transmission: Respiratory or salivary secretions are expelled from infected individual

Answer 45

Droplet

Question 46

_________ transmission: Involve small particles from the respiratory tract; Suspended in air and can travel farther than droplets

Answer 46

Aerosol

Question 47

__________: Insect or animal is an intermediate host

Answer 47

Vector-borne

Question 48

Nosocomial Infections

Answer 48

◦ Occur in health care facilities- Hospitals, nursing homes, physician’s offices, dental offices ◦ 10% to 15% of patients acquire an infection in the hospital because of: ~Many microbes present ~Patients with undiagnosed infectious disease ~Shared environment ~Treatment that may cause weakened immune system ~Many health care workers and fomites act as reservoirs.

Question 49

Factors That Decrease Host Resistance

Answer 49

◦ Age (infants and older adults) ◦ Pregnancy ◦ Genetic susceptibility ◦ Immunodeficiency ◦ Malnutrition ◦ Chronic disease ◦ Severe physical or emotional stress ◦ Inflammation or trauma ◦ Impaired inflammatory responses

Question 50

Pathogenicity:

Answer 50

capability of a microbe to cause disease

Question 51

Virulence

Answer 51

◦ Degree of pathogenicity ◦ Invasive qualities (e.g., motility or enzymes) ◦ Toxins ◦ Adherence to tissue by pili, fimbriae, specific receptor sites ◦ Ability to avoid host defenses

Question 52

Infection control requires two approaches:

Answer 52

◦ Standard Precautions used in all settings with all clients when body fluids may be exchanged. ◦ Specific Precautions in clients diagnosed with a particular infection—these are used in addition to standard precautions.

Question 53

Incubation period

Answer 53

◦ Time between entry of organism into the body and appearance of clinical signs of disease ◦ Vary considerable with different organisms

Question 54

Prodromal period

Answer 54

◦ Fatigue, loss of appetite, headache ◦ Nonspecific—“coming down with something” ◦ More evident in some infections than others

Question 55

Acute period

Answer 55

Infectious disease develops fully

Question 56

Sterilization of equipment by:

Answer 56

◦ Chemicals ◦ Heat in an autoclave ◦ NOTE: Equipment must be cleaned prior to sterilization or it will remain contaminated!

Question 57

Use of chemicals:

Answer 57

◦ Antiseptics are used on the skin and tissues. ◦ Disinfectants are used on surfaces or objects.

Question 58

Local VS system signs of inflammation

Answer 58

Local ◦ Pain, swelling, redness, warmth ◦ If bacterial—purulent exudate ◦ If viral—serous, clear exudate Systemic ◦ Fever may be present. ◦ Fatigue and weakness ◦ Headache ◦ Nausea

Question 59

Methods of Diagnosis

Answer 59

◦ Culture and staining techniques ◦ Blood tests [Leukocytosis—bacterial infection] [Leukopenia—viral infection] ~Differential count ~C-reactive protein ~Erythrocyte sedimentation rate (ESR) ◦ Immunological testing of body fluids ~Antigen identification/titer

Question 60

If drug resistance is known to occur with infection, use:

Answer 60

multidrug therapy.

Question 61

Antibiotic- Drugs derived from :

Answer 61

organisms

Question 62

Bactericidal- drugs destroy :

Answer 62

organism

Question 63

Bacteriostatic- decrease rate of :

Answer 63

reproduction

Question 64

Broad VS narrow spectrum antimicrobials

Answer 64

broad spectrum- Effective against both gram-positive and gram-negative organisms narrow spectrum- Effective against either gram-positive or gram-negative organisms

Question 65

First- VS second-generation drugs

Answer 65

◦ 1st gen—original drug class ◦ 2nd gen—later version, which may be more effective, more tolerable/ easily administered

Question 66

Mode of Actions of antibiotics with an example of each

Answer 66

◦ Interfere with bacterial cell wall synthesis- penicillin ◦ Increase permeability of bacterial cell membrane- polymyxin ◦ Interfere with protein synthesis- tetracycline ◦ Interfere with synthesis of essential metabolites- sulfonamides

Question 67

Mode of Actions of Antivirals (3)

Answer 67

◦ Blocking entry into host cell ◦ Inhibiting gene expression ◦ Inhibiting assembly of the virus

Question 68

Antifungal Agents ◦ May interfere with___________ in fungi ◦ May increase fungal membrane __________ ◦ Most antifungal agents administered topically to skin or mucous membranes ◦ Fungi are eukaryotic cells and are therefore often toxic to animal and human cells. ~Treatment requires strict medical supervision

Answer 68

◦ May interfere with mitosis in fungi ◦ May increase fungal membrane permeability ◦ Most antifungal agents administered topically to skin or mucous membranes ◦ Fungi are eukaryotic cells and are therefore often toxic to animal and human cells. ~Treatment requires strict medical supervision

Question 69

Antiprotozoal agents

Answer 69

◦ Similar characteristics to antifungal agents ◦ Protozoans are eukaryotic cells. ◦ Many pathogenic protozoa have several stages in their life cycles. ◦ Require treatment with different agents at different stages of the cycles

Question 70

-Trichomoniasis -Malaria -Amebic dysentery are all

Answer 70

protozoal diseases