Bacterial Classification

Question 1

gram-negative bacteria stain __[color]___ because their cell wall consists of ____, whereas gram-positive bacteria stain ____ because their cell wall is _____.

Answer 1

Gram-negative bacteria stain pink because their cell wall consists of a thin peptidoglycan layer surrounded by a second outer membrane, whereas gram-positive bacteria stain purple because their cell wall is a thick peptidoglycan layer and no outer cell membrane.

Question 2

Gram-negative bacteria generally have a _____ MIC compared to gram-positive bacteria.

Answer 2

higher

Question 3

Bacteria with a cell wall can be grouped as ____ or _____. Bacteria without a cell wall include ____ and ____.

Answer 3

Bacteria with a cell wall can be grouped as gram-negative or gram-positive. Bacteria without a cell wall include Mycoplasmas and L-form bacteria (bacteria that have lost their wall due to mutation or environmental conditions)

Question 4

Bacteria that do not require any special conditions or substances for their growth are called ______. Examples include ______

Answer 4

non-fastidious bacteria; Enterobacterales, psuedomonas, staphylococcus, streptococcus

Question 5

The laboratory should be informed if certain fastidious bacteria are suspected including ___ [name 5]___

Answer 5

Campylobacter, Mycoplasma, Actinomyces, Nocardia, Mycobacterium

Question 6

MacConkey agar is selective for _____ and can differentiate between _______

Answer 6

selective for gram-negative bacteria, differentiates lactose fermenting from non-lactose fermenting

Question 7

What enterobacterales turn pink on MacConkey agar and why?

Answer 7

E coli, Klebsiella and Enterobacter turn pink because they ferment lactose.

Question 8

What are the two major groups of gram-negative rods?

Answer 8

Enterobacterales and non-enterobacterales

Question 9

Enterobacterales are non-spore forming, non-acid fast, ___[growth requirement]___, gram-_____ rods. They all grow on _____ agar. They posses a _____ (K antigen) and may be motile via ____ (H antigen).

Answer 9

Enterobacterales are non-spore forming, non-acid fast, facultative anaerobic, gram-negative rods. They all grow on MacConkey agar. They posses a capsule (K antigen) and may be motile via flagella (H antigen).

Question 10

Name 9 clinically significant enterobacterales

Answer 10

E coli, Proteus, Salmonella, Enterobacter, Citrobacter, Serratia, Klebsiella, Providencia, Yersinia spp

Question 11

Name 4 clinically significant non-enterobacterales

Answer 11

pasteurella multocida, psuedomonas aegurinosa, Acinetobacter and Ralstonia

Question 12

Pasteurella are fastidious, gram-_____ __[shape]___ that are classified as _____ and grow on __[media]___ at ___ degrees celcius.

Answer 12

Pasteurella are fastidious, gram-negative bacilli/coccobacilli that are classified as non-enterobacterales and grow on 5% sheep blood agar at 37 degrees celcius.

Question 13

Psuedomonas aeruginosa are gram-____ __[shape]__ that produce a variety of _____ and have a ____ appearance in culture. Psuedomonas have almost every type of ____ factor and can develop resistance to _____. An MDR psuedomonas infection may be treated with a ______ alone or in combination with a _____ or a ____.

Answer 13

Psuedomonas aeruginosa are gram-negative rods that produce a variety of pigments and have a mucoid appearance in culture. Psuedomonas have almost every type of virulence factor and can develop resistance to βlactams. MDR psuedomonas can be treated with antipsuedomonal βlactam (carbapenems, ceftazidime) alone or in comibation with aminoglycosides (especially amikacin) or a flouroquinolone.

Question 14

Name 6 coccobacilli or spiral shaped gram negative bacteria that are clinically significant

Answer 14

Bartonella, Bordetella, Campylobacter, Francisella, Helicobacter, Brucella

Question 15

List 5 uncommon gram-positive bacterial infections in dogs and cats

Answer 15

rhodococcus equi, corynebacterium spp, listeria monocytogenes, erysipelothrix spp, bacillus anthracis

Question 16

Anaerobic bacteria are associated with what clinical lesions?

Answer 16

Abscess formation in a variety of tissues, pyothorax, peritonitis, pyometra, periodontal disease, osteomyelitis, bacteremia

Question 17

Anaerobic bacteria can be classified into what four groups?

Answer 17

Gram-negative bacilli, gram-positive non-spore forming bacilli (Actinomyces), gram-positive spore-forming bacilli (Clostridium) and gram-positive cocci (peptostreptococcus)

Question 18

The clinically significant gram-negative anaerobes are:

Answer 18

Bacterioides, Fusobacterium, Porphyroonas, Prevotella

Question 19

Actinomyces spp are gram-____ __[shape]__. Theynon-spore forming and are considered _[growth requirement]__.

Answer 19

Actinomyces spp are gram-positive filamentous rods. They are non spore forming and considered microaerophillic or anaerobic.

Question 20

Anaerobes are inherently resistant to which antibiotic groups?

Answer 20

Aminoglycosides (amikacin, gentamicin, neomycin, tobramycin, kanamycin), second-gen quinolones (

Question 21

Staphylococcus are catalase-____, gram-____ __[shape]___that are __[growth requirement]__. The most virulent staphylococcus species are _____ and these 3 species are ____.

Answer 21

Staphylococcus are catalase-positive, gram-positive cocci that are facultatively anaerobic. The most virulent staphylococcus species are coagulase-positive and these 3 species are staph aureus, staph psuedintermedius and staph schleiferi.

Question 22

The catalase test differentiates bacteria based on their ability to _____. It is commonly used to differentiate the gram-positive cocci ____ and ____.

Answer 22

The catalase test differentiates bacteria based on their ability to detoxify hydrogen peroxide. Differentiates catalase-positive staph from catalase-negative strep.

Question 23

Bordetella bronchiseptica is an _[growth requirement]__, gram-____, motile __[shape]___.

Answer 23

Bordetella is an aerobic, gram-negative motile coccobacillus

Question 24

Cat scratch disease is caused by ______ transmitted from cat scratches or bites. In humans CSD is characterized by a _____ at the site of innoculation followed by local ____ and malaise. _[age]__ cats are implicated because they are more likely to be _____.

Question 25

Bartonella spp cause ___ in humans and may cause ____ in dogs and cats. They are fastidious, facultative ____, gram-_____ bacteria transmitted by ____ in cats and potentially by other vectors like ____ in dogs.

Answer 25

Bartonella spp cause “cat scratch disease” in humans and may cause endocarditis in dogs and cats. They are fastidious, facultative intracellular, gram-negative bacteria transmitted by ctenocephalides felis (cat flea) in cats and potentially by other vectors like mites, ticks and lice in dogs.

Question 26

Tetanus and botulism are neurologic diseases caused by the toxins of _____ and ___, respectively. These environmentally ubiquitous organisms are gram-______, __[growth requirement]___, spore-forming, ___-shaped bacteria, with worldwide distributions. The spores of both are extremely hardy in the environment and resist boiling and disinfection with ____ or _____.

Answer 26

Tetanus and botulism are neurologic diseases caused by the toxins of Clostridium tetani and Clostridium botulinum, respectively. These environmentally ubiquitous organisms are gram-positive, anaerobic, spore-forming, rod-shaped bacteria, with worldwide distributions. The spores of C. tetani and C. botulinum are extremely hardy in the envi- ronment and resist boiling and disinfection with alcohol or formalin.

Question 27

Most cases are canine botulism and all feline botulism cases are due to type ____ BoNT toxin.

Answer 27

Type C

Question 28

Tetanus occurs when ______ spores are introduced via _____, where they replicate and make ____ and ____ in _____ conditions. (____ is NOT a route of transmission because _____). ___ toxin promotes ______ while _____ toxin binds to _____ and travels by _____ to inhibitory interneurons in the brain and spinal cord. Here it interferes with the release of inhibitory neurotransmitter _____ and ____, causing the clinical signs of spastic rigidity.

Answer 28

Tetanus occurs when Clostridium tetani spores are introduced via tissue penetration, where they replicate and make Tetanosapsmin and Tetanolysin in anaerobic conditions. (Ingestion is NOT a route of transmission because GI secretions detroy tentanospasmin). Tetanolysin toxin promotes local tissue degredation while Tetanospasmin toxin binds to lower motor neurons and travels by retrograde axonal transport to inhibitory interneurons in the brain and spinal cord. Here it interferes with the release of gaba and glycine, causing the clinical signs of spastic rigidity.

Question 29

____ causes plague and is a nonmotile, non-spore forming, __[growth requirement]__, gram-____, bipolar staining bacteirum.

Answer 29

Yersinia pestis causes plague and is a nonmotile, non-spore forming, facultative anaerobic, gram-negative bipolar staining bacteirum.

Question 30

Tularemia (also known as rabbit fever, hare fever, deerfly fever, and lemming fever) is an extremely infectious but uncommon zoonotic disease caused by ______, a small, non-motile, __[growth requirement]__, facultative ____, gram-____ __[shape]___ . The name “tularemia” comes from the first isolation of the organism from sick ground squirrels in _____, California.

Answer 30

Tularemia (also known as rabbit fever, hare fever, deerfly fever, and lemming fever) is an extremely infectious but uncommon zoonotic disease caused by Francisella tularenesis, a small, non-motile, aerobic, facultative intracellular, gram-negative coccobacillus. The name “tularemia” comes from the first isolation of the organism from sick ground squirrels in Tulare County, California.

Question 31

Tularemia can be transmitted by what four mechanisms? What are the two most common vectors?

Answer 31

can be transmitted by arthropod bites, inhalation or ingestion of the organism (ie ingestion of an infected rodent or rabbit by a cat or dog), and direct skin contact with infected tissues (probably when there are minute breaks in the skin). Dermacentor and Ambylomma ticks.

Question 32

Plague and Tularemia are both gram-____ ___[shape]__ that can cause fever and lymphadenopathy. However ____ grows on routine culture and ____ does not.

Answer 32

Plague and Tularemia are both gram-negative coccobacilli/bacilli that can cause fever and lymphadenopathy. However Yersinia sppp grows on routine culture and Francisella tularensis does not.

Question 33

Serotype B

Answer 33

Salmonella Typhimurium

Question 34

Serotype C1

Answer 34

Salmonella Choleraesuis and Salmonella Montevideo

Question 35

Serotype C2

Answer 35

Salmonella Newport

Question 36

Serotype D

Answer 36

Salmonella Dublin and Salmonella Enteritidis (specific to poultry)

Question 37

Serotype E1

Answer 37

Salmonella Muenster

Question 38

Serotype K

Answer 38

Salmonella Cerro

Question 39

Salmonella Typhimurium

Answer 39

gram negative facultative anaerobe