Chapter 28,29 and 30

Question 1

What are the general characteristics of Eikenella?

Answer 1

• –Asaccharolytic
• –Oxidase positive
• -They don’t grow on MacConkey agar because they have high nutritional needs and they require enrichment media such as chocolate agar to grow

Question 2

Describe the normal habitat for Eikenella spp. and situations that provide optimal conditions for the opportunistic bacteria to become a pathogen.

Answer 2

Eikenella corrodens is the only member that can be found as normal flora
They are transmitted from person to person through human bites and fist wounds
They are associated with endocarditis because they are part of the HACEK group of organisms

Question 3

Define the acronym HACEK. To what organisms does this acronym refer, and what medical conditions are associated with these organisms?

Answer 3

The HACEK group of organisms are described as being slow-growing gram negative bacilli, they are fastidiou organisms and they are associated with endocarditis 
H-Haemophilus aphrophilus 
A-Actinobacillus actinomycetemcomitans 
C-Cardiobacterium gominis 
E-Eikenella corrodens 
K-Kingella kingae

Question 4

What is the microscopic appearance of Eikenella corrodens?

Answer 4

Slender, gram-negative rods, straight rod with rounded ends

Question 5

What is the appearance of Eikenella corrodens on a Blood agar ?

Answer 5

Moist, clear centers surrounded by flat, spreading growth colonies, colonies may be pit or corrode the agar surface

Question 6

What are the general characteristics of Pasteurella?

Answer 6

Small, gram-negative bacilli
Non-motile
Oxidase positive
Will not grow on MacConkey because of their fastidious nature, they require high nutritional needs therefore they will grow on enrichment agar like the blood and chocolate agar

Question 7

Where are pasturella organisms commonly found? and how are they transmitted?

Answer 7

They ae normally found in domestic and wild animals

Transmission: They are transmitted through a bite or scratch of veterinary hosts

Question 8

What is the colony morphology of P.multocida on BA?

Answer 8

They are convex, smooth, gray, non-hemolytic, rough with a musty odor

Question 9

What is the microscopic appearance of Pasteurella species?

Answer 9

Exhibits short, straight bacilli with bipolar staining

Question 10

What is the treatment for pasteurella?

Answer 10

They are susceptible to penicillin

Empiric therapy is effective for bite wounds complicated by polymicrobial infection

Question 11

What are the general characteristics of the bacteria?

Answer 11

They are dysgonic meaning that they are slow growing
They ferment glucose
fastidious
MacConkey negative
Are capniphilic ( CO2 incubation with moist environment)

Question 12

What are the habitat and how are they transmitted?

Answer 12

They are normally found in the nasopharynx or oral cavity
They have low virulence meaning that they can only cause infections when it enters a sterile sites (Bites, Droplets, manipulations in the oral cavity)

Question 13

What are the antimicrobial therapy used for theses bacteria?

Answer 13

Most infections are treated with beta-lactam antibiotics

Question 14

What are the microscopic appearance of these organisms?

Answer 14

–Aggregatibacter spp.(hemophillus)
A. aphrophilus—Very short bacilli, occasionally filamentous
A. segnis—Pleomorphic rods
–Actinobacillus spp.
Short to very short gram-negative bacilli
–Kingella spp.
Short, plump coccobacilli with squared-off ends
–Cardiobacterium spp.
C. hominis—Pleomorphic with one rounded end and one tapered end appearing as a teardrop