Lesson 2

Question 1

Describe bacterial morphology based
on the shape and arrangement of the
cells.

Answer 1

Bacteria may be organized into the following three groups according to their shape:

1. Coccus (pl., cocci)
2. Bacillus (pl., bacilli)
3. Spiral (spirochetes)
4. Pleomorphic: shapes that range from cocci to rods

Question 2

List and define the terms used
to characterize bacterial requirements
for oxygen.

Answer 2

• obligate aerobes: Bacteria that require oxygen to survive.
• obligate anaerobes: Bacteria that are killed in the presence of oxygen or those with growth that is inhibited in the presence of oxygen
• Facultative anaerobes: organisms that can survive in the absence of oxygen, but their growth is limited. -Microaerophilic bacteria: prefer reduced oxygen tension.
• capnophilic bacteria: require high levels of carbon dioxide.

Question 3

Coccus (pl., cocci)

Answer 3

spherical cells, such as Staphylococcus aureus, which is the causative agent of mastitis in animals

Question 4

Bacillus (pl., bacilli)

Answer 4

shaped like rods or cylinders, such as Bacillus anthracis, which is the causative agent of anthrax in animals and human beings

Question 5

Spiral (spirochetes)

Answer 5

usually occur singly and can be subdivided into loose spirals, such as Borrelia anserina, which causes avian borreliosis; tight spirals, such as Leptospira pomona, which causes red water disease in cattle; and comma-shaped spirals, such as Campylobacter fetus, which causes abortion in cattle

Question 6

List and define the terms used
to characterize bacterial requirements
for temperature

Answer 6

• mesophiles: nearly all bacteria that are pathogenic to animals grow best at 20° C to 40° C
• psychrophiles: Bacteria with lower temperature requirements
• thermophiles: Bacteria with higher temperature requirements.

Question 7

List and describe specialized structures
and organelles that are present in
some species of bacteria

Answer 7

Spores vary in the size, shape, and location within the cell. There’s three different classifications which are central, subterminal, and terminal.

Question 8

Terminal

Answer 8

Present at the end or pole of the cell, such as Clostridium tetani

Question 9

Subterminal

Answer 9

Present near the end of the cell, such as Clostridium chauvoei

Question 10

Central

Answer 10

Present in the center of the cell, such as Bacillus anthracis

Question 11

List the equipment and supplies
needed to perform microbiology, cytology and urinalysis in the practice
laboratory

Answer 11

A microscope
a refractometer
a microhematocrit centrifuge
a clinical centrifuge
blood chemistry analyzers
cell counters
water baths
incubators
test tubes
pipettes
heat blocks
aliquot mixers.

Question 12

Describe sample collection for micro -

biologic samples

Answer 12

The preferred blood source is almost always venous blood. Jugular blood collection is most appropriate in common veterinary species. In some exotic species, there are no readily accessible veins, so it may be necessary to collect peripheral or capillary blood samples in those cases. The blood collection site must be cleaned and swabbed with alcohol before collection. The alcohol should be allowed to dry before proceeding with the sample collection. The animal must be restrained, preferably with minimal manual restraint. Every effort should be made to minimize stress in the patient, because it often compromises the sample.