Question 1

Which of the following bones is used for the collection of red bone marrow in adults?

Accepted Answer

In adults, red bone marrow, which is involved in the production of blood cells, is primarily found in flat bones like the pelvis and sternum.

Question 2

Infections of the _____________ in children and young adults can affect their height.

Accepted Answer

Infections of the growth plate (also known as the epiphyseal plate or physis) in children and young adults can affect their height because the growth plate is responsible for longitudinal bone growth. Damage or infection in this area can disrupt normal bone development and growth.

Question 3

An individual who steps on a nail and then develops osteomyelitis due to Staphylococcus aureus is described as having acquired the organism via

Accepted Answer

Direct inoculation occurs when bacteria are introduced directly into the body, as in the case of stepping on a nail, which can introduce Staphylococcus aureus directly into the bone, leading to osteomyelitis.

Question 4

A 20-year-old intravenous drug user develops osteomyelitis of the elbow. In the emergency room, she confesses to licking the hypodermic needle to make it easier to insert into her skin. Which of the following organisms is most likely to be the cause of her osteomyelitis?

Accepted Answer

The answer of A 20-year-old intravenous drug user develops osteomyelitis...

Question 5

Which of the following individuals has the potential for disseminated disease resulting in septic arthritis?

Accepted Answer

All of the options listed have potential risk factors for developing septic arthritis. A) Animal bites can introduce bacteria into the body, leading to infection and potentially septic arthritis. B) Sexually active individuals, especially those with urethritis, can develop septic arthritis as a complication of sexually transmitted infections. C) Surgical procedures, such as hip replacements, can introduce bacteria into the body, leading to infection and potentially septic arthritis.

Question 6

Which of the following collection and transportation methods is most for culture of joint fluid?

Accepted Answer

Blood culture broth is the most suitable method for collecting and transporting joint fluid for culture because it provides an optimal environment for the growth of bacteria, increasing the likelihood of detecting any pathogens present.

Question 7

The most sensitive specimen for the diagnosis of Brucella infection is

Accepted Answer

Bone marrow is considered the most sensitive specimen for the diagnosis of Brucella infection because it provides a higher yield of the organism compared to blood cultures, especially in chronic cases of the disease.

Question 8

The diagnosis of osteomyelitis requires

Accepted Answer

The answer of The diagnosis of osteomyelitis requires
...

Question 9

A bone biopsy is received in the microbiology laboratory in a sterile cup with 10% formalin. You will

Accepted Answer

Formalin is a fixative used in histology to preserve tissues, but it is not suitable for microbiological cultures because it kills bacteria, making it impossible to grow them for identification. Therefore, a bone biopsy intended for microbiological analysis should not be in formalin, and the specimen should be rejected.

Question 10

Which of the following media is most important when processing bone, joint fluid, and bone marrow?

Accepted Answer

Chocolate agar is most important when processing bone, joint fluid, and bone marrow because it contains nutrients that are essential for the growth of bacteria that cause bone and joint infections.

Question 11

The culture agar plates for the isolation of __________________ must be held a minimum of 30 days in humidified CO₂.

Accepted Answer

The answer of The culture agar plates for the isolation...

Question 12

A farmer has been losing weight and has developed a fever that seems to come and go over the last three months. On visiting his physician, samples are submitted to the
Laboratory. What types of specimens are appropriate for collection?

Accepted Answer

Blood and bone marrow samples are appropriate for diagnosing conditions that could cause symptoms like weight loss and intermittent fever, especially in a farmer who might be exposed to zoonotic infections or other pathogens that could affect blood and bone marrow.

Question 13

A 68-year-old female is hospitalized after a complete knee replacement. The joint becomes hot and red two days after surgery. An aspirate of the joint is sent to the laboratory. Which of the following organisms would be considered a significant isolate from this body site?

Accepted Answer

All of the options listed are significant isolates from a joint infection site. Catalase-positive, coagulase-negative, gram-positive cocci (often Staphylococcus epidermidis) are common skin flora but can be significant pathogens in prosthetic joint infections. Catalase-positive, coagulase-positive, gram-positive cocci (Staphylococcus aureus) are well-known pathogens that can cause severe infections, including in prosthetic joints. Catalase-positive, indole-positive, anaerobic, non-sporeforming, gram-positive rods could represent organisms like Cutibacterium acnes (formerly Propionibacterium acnes), which, while less common, can still cause significant infections, especially in prosthetic devices.

Question 14

Which of the following fastidious oral organisms is associated with septic arthritis and osteomyelitis in children under the age of 2 with a recent history of an upper respiratory tract infection?

Accepted Answer

Kingella kingae is a fastidious gram-negative organism that is increasingly recognized as a cause of septic arthritis and osteomyelitis in young children, often following an upper respiratory tract infection.

Question 15

A sterile arthritis may occur after

Accepted Answer

Sterile arthritis, also known as reactive arthritis, can occur after a tick bite due to the body's immune response to the infection, such as Lyme disease, without the presence of live bacteria in the joint.

Question 16

A 17-year-old male develops septic arthritis in his left knee. His physician aspirates synovial fluid and sends it to the microbiology laboratory. A direct Gram stain of the fluid is demonstrated in the image provided.
 Source: CDC/Joe Millar
Which of the following tests is necessary for definitive identification of this
Organism?

Accepted Answer

The answer of A 17-year-old male develops septic arthritis in...

Question 17

A 28-year-old male received a compound fracture of his right arm after a motorcycle accident. Three days after the arm has been set, purulent material is observed from under his bandages. An aerobic and anaerobic culture of the wound site is sent to the microbiology department. A direct Gram stain of the wound is demonstrated in the image provided.
 Source: CDC and Don Stalons
If the organism proved to be catalase negative, you observed the colony on

Accepted Answer

The answer of A 28-year-old male received a compound fracture...

Question 18

A 7-year-old male hits his left leg shin on the metal edge of a stair step of his school bus. Two days after, his shin is swollen, hot, and red. His mom notices a trickle of pus from an opening. A visit to his pediatrician involves an x-ray of the injured site. It shows a lesion on his left tibia. If the responsible organism possesses protein A and can produce clumping factor, it should be screened for resistance to

Accepted Answer

The organism likely responsible for the infection is Staphylococcus aureus, indicated by the presence of protein A and clumping factor. Screening for resistance to cefoxitin is used to detect methicillin-resistant Staphylococcus aureus (MRSA).

Question 19

A 28-year-old male has had his wisdom teeth removed. Two weeks after the procedure, he develops swelling along the right jaw line in the area where his wisdom teeth were removed. His physician aspirates a pocket of pus within the jaw. The direct Gram stain of the aspirate is demonstrated in the image provided.
 Source: CDC
This organism is known for the production of

Accepted Answer

The answer of A 28-year-old male has had his wisdom...

Question 20

A child with sickle cell anemia is prone to osteomyelitis caused by

Accepted Answer

Children with sickle cell anemia are more prone to osteomyelitis caused by Salmonella spp. due to their increased susceptibility to infections and the peculiarities of their blood circulation.

Quiz 39: Skeletal System