Lecture 4

Question 1

Vaccination

Answer 1

• involves the production of immunity following the injection of an antigen

Question 2

the antigen in a vaccination

Answer 2

The antigen can be a dead (completely inactivated) infectious agent, or a weakened (attenuated) infectious agent. Parts of the infectious agent can also be used for this purpose.

Question 3

Recombinant DNA technology and genetic

engineering are oftentimes used to

Answer 3

used to produce antigenic parts of infectious agents

Question 4

Inoculation

Answer 4

involves the injection of a suspension of infectious agent to produce disease. It can also be thought of as the implantation of an organism upon a growth medium to just produce growth of an organism.

Question 5

Taxonomy

Answer 5

science of classification

Question 6

Binomial nomenclature

Answer 6

established by Carolus Linnaeus in 1735. Each organism is assigned two names, a Genus and a species epithet

Question 7

descriptive

Answer 7

Bacterial names can be descriptive
For example Staphylococcus aureus (etiologic agent for Toxic Shock Syndrome-fever, vomiting and rash), comes from the Greek words staphyle (bunch of grapes) and
kokkos (berry). The word aureus comes from Latin and means golden.

Question 8

names

Answer 8

Bacterial names come from the names of the scientists that either discovered or worked with the organisms.
Pasteurella multocida the organism that causes chicken cholera, was named after Louis Pasteur.

Question 9

Yersinia pestis

Answer 9

Alexandra Yersin named the genus Yersinia. Yersinia pestis is the etiologic agent that causes
plague

Question 10

Rickettsia rickettsii

Answer 10

Harold Ricketts lent his name to the genus Rickettsia. Rickettsia rickettsii is the etiologic agent that causes tick-borne Rocky Mountain Spotted Fever. Rickettsia prowazekii is responsible for causing the louse-borne epidemic typhus. Harold Ricketts died of rickettsial infection.

Question 11

Neisseria

Answer 11

Albert Neisser named the genus Neisseria. These bacteria are Gram negative diplococci. Neisseria gonorrhoeae is the etiologic agent that causes the venereal disease known as gonorrhea. Neisseria meningitidis causes meningococcal meningitis

Question 12

Erwinia carotovora

Answer 12

Erwin Smith, a plant pathologist lent his name to the bacterial organism that causes soft-rot in vegetables. The organism Erwinia carotovora, incorporates the first name of this scientist.

Question 13

bacillus

Answer 13

if lower case means small rod

used interchangeably with word rod

Question 14

Common names

Answer 14

are often used. For example instead of Streptococcus pneumoniae, these can be called
Pneumococci. Instead of Neisseria gonorrhoeae, these can be called Gonococci. Neisseria meningitidis
can be referred to as Meningococci

Question 15

Spherical characteristics

Answer 15

(cocci – plural, coccus – singular) These display the following characteristics

1. Least surface area per unit volume
2. They are more resistant to drying
3. Grow more slowly
4. Most are non-motile

Question 16

When examining bacterial organisms, we look at both

Answer 16

shape (morphology) and arrangement
Theorganisms must be able to spread out on a slide in a single layer (monolayer) with room between the
characteristic arrangements. Depending upon the species, the organisms may be arranged as singles,
pairs, chains, groups of two or four (tetrads), groups of eight (box cars), irregular clusters, or
combinations.

Question 17

Streptococcus pneumoniae

Answer 17

• Gram positive diplococci

Question 18

Neisseria gonorrhoeae

Answer 18

Gram negative diplococci

Question 19

Streptococcus pyogenes

Answer 19

• Gram positive cocci that form chains

Question 20

Growth of Streptococci on Blood Agar

plates can reveal

Answer 20

different patterns of hemolysis

Question 21

Alpha (partial) hemolytic types

Answer 21

produce a greenish colored clearing

Question 22

Beta (complete) hemolytic types

Answer 22

produce a complete clearing

most dangerous type

Question 23

Gamma (no hemolysis) hemolytic types

Answer 23

produce no hemolyis or red blood cell breakdown at all.

Question 24

Micrococcus luteus and Micrococcus agilis

Answer 24

• Gram positive cocci that form pairs and tetrads

harmless organism

Question 25

Sarcina lutea

Answer 25

Gram positive cocci that form packets of 8 (box cars)

Question 26

Staphylococcus aureus

Answer 26

Gram positive cocci that form irregular (grape-like) clusters

Question 27

Rods characteristics

Answer 27

(bacilli – plural, bacillus – singular) These display the following characteristics:

1. More surface area per unit volume
2. They are less resistant to drying
3. Grow more rapidly
4. Many species are motile

Question 28

Arrangements

Answer 28

vary with the species. Singles, pairs, chains(short ends attached), chains (long ends attached – called palisades layering or picket fence or match stick patterns), chains with branched patterns, chains where the cross walls between cells have broken or failed to form (called filaments)

Question 29

Many of the Gram negative rod species display a

Answer 29

combination of the above mentioned arrangements.
Also, oftentimes the Gram negative rod cultures consist of very small cells. When observed it can be
difficult to determine their shape (morphology)
Under the microscope they may appear to be cocci due
to their small size. They are however, classified as rods. We sometimes describe them as coccobacilliary
in shape.

Question 30

Bacillus cereus

Answer 30

• Gram positive rods that form chains

Question 31

Corynebacterium diphtheriae

Answer 31

Gram positive rods that will oftentimes arrange in palisades layers. This organism is the etiologic agent of diphtheria (sore throat, low fever, membrane on tonsils and/pharynx).

Question 32

Mycobacterium tuberculosis

Answer 32

Weakly Gram positive, strongly acid fast positive rods that can appear as branched chains. Causes the disease known as tuberculosis.

Question 33

Escherichia coli

Answer 33

Gram negative rods and coccobacilliary forms. They appear as singles, pairs and short chains. Filaments are sometimes observed. This is the etiologic agent for Travelers’ diarrhea (watery diarrhea and cramps)

Question 34

Pseudomonas aeruginosa

Answer 34

Gram negative rods and coccobacilliary forms. They appear as singles, pairs and short chains. Filaments are sometimes observed. Called the blue-pus organism. Infects burn victims and those that are immunocompromised

Question 35

Spiral or Helical characteristics

Answer 35

(Spiral is short, Helical if long) These display the following characteristics:

1. Almost all are motile
2. They appear as singles (swim apart)
3. Move through the media in a corkscrew fashion

Question 36

Spiral or Helical Major groups

Answer 36

Spirilla
Spirochetes
Vibrios

Question 37

Spirilla

Answer 37

(Spirillum – singular) – rigid long axis with polar flagella

no flexibility, common in pond water

Question 38

Spirochetes

Answer 38

flexible long axis. No polar flagella. They possess axial filaments. They coil and then release much like a spring to move

Question 39

Vibrios

Answer 39

incomplete spirals. They look like commas.

very fast

Question 40

Borrelia burgdorferi

Answer 40

spirochetes, Gram negative etiologic agent for tick-borne Lyme disease

Question 41

Treponema pallidum

Answer 41

• spirochetes, Gram negative etiologic agent for the venereal disease called syphilis

Question 42

Vibrio cholerae

Answer 42

• vibrios, Gram negative etiologic agent for human cholera.

Question 43

Pleomorphic

Answer 43

– more than one shape . Environmental conditions can alter the shape of some bacteria.
Some bacteria are genetically pleomorphic.

Question 44

Members of the genus Mycoplasma are

Answer 44

pleomorphic. These organisms are considered to be the
smallest of the free-living bacteria. They lack cell walls or have incomplete cell walls. They favor hyper
osmotic fluids such as rich lung exudates. This prevents cell lysis as they lack cell walls

Question 45

Mycoplasma pneumoniae

Answer 45

• etiologic agent of Primary Atypical Pneumonia

Question 46

Hemophilus influenzae

Answer 46

• Gram negative bacterial organism that can cause upper respiratory problems
  (mimics influenza virus). Can also cause otitis media and meningitis. Usually seen in younger children.